aboutsummaryrefslogtreecommitdiff
path: root/libstdc++-v3/docs/html/ext/lwg-defects.html
blob: 94e4cb0a5d4e5191c5909f6cca1daa0fd466df3b (plain) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
4203
4204
4205
4206
4207
4208
4209
4210
4211
4212
4213
4214
4215
4216
4217
4218
4219
4220
4221
4222
4223
4224
4225
4226
4227
4228
4229
4230
4231
4232
4233
4234
4235
4236
4237
4238
4239
4240
4241
4242
4243
4244
4245
4246
4247
4248
4249
4250
4251
4252
4253
4254
4255
4256
4257
4258
4259
4260
4261
4262
4263
4264
4265
4266
4267
4268
4269
4270
4271
4272
4273
4274
4275
4276
4277
4278
4279
4280
4281
4282
4283
4284
4285
4286
4287
4288
4289
4290
4291
4292
4293
4294
4295
4296
4297
4298
4299
4300
4301
4302
4303
4304
4305
4306
4307
4308
4309
4310
4311
4312
4313
4314
4315
4316
4317
4318
4319
4320
4321
4322
4323
4324
4325
4326
4327
4328
4329
4330
4331
4332
4333
4334
4335
4336
4337
4338
4339
4340
4341
4342
4343
4344
4345
4346
4347
4348
4349
4350
4351
4352
4353
4354
4355
4356
4357
4358
4359
4360
4361
4362
4363
4364
4365
4366
4367
4368
4369
4370
4371
4372
4373
4374
4375
4376
4377
4378
4379
4380
4381
4382
4383
4384
4385
4386
4387
4388
4389
4390
4391
4392
4393
4394
4395
4396
4397
4398
4399
4400
4401
4402
4403
4404
4405
4406
4407
4408
4409
4410
4411
4412
4413
4414
4415
4416
4417
4418
4419
4420
4421
4422
4423
4424
4425
4426
4427
4428
4429
4430
4431
4432
4433
4434
4435
4436
4437
4438
4439
4440
4441
4442
4443
4444
4445
4446
4447
4448
4449
4450
4451
4452
4453
4454
4455
4456
4457
4458
4459
4460
4461
4462
4463
4464
4465
4466
4467
4468
4469
4470
4471
4472
4473
4474
4475
4476
4477
4478
4479
4480
4481
4482
4483
4484
4485
4486
4487
4488
4489
4490
4491
4492
4493
4494
4495
4496
4497
4498
4499
4500
4501
4502
4503
4504
4505
4506
4507
4508
4509
4510
4511
4512
4513
4514
4515
4516
4517
4518
4519
4520
4521
4522
4523
4524
4525
4526
4527
4528
4529
4530
4531
4532
4533
4534
4535
4536
4537
4538
4539
4540
4541
4542
4543
4544
4545
4546
4547
4548
4549
4550
4551
4552
4553
4554
4555
4556
4557
4558
4559
4560
4561
4562
4563
4564
4565
4566
4567
4568
4569
4570
4571
4572
4573
4574
4575
4576
4577
4578
4579
4580
4581
4582
4583
4584
4585
4586
4587
4588
4589
4590
4591
4592
4593
4594
4595
4596
4597
4598
4599
4600
4601
4602
4603
4604
4605
4606
4607
4608
4609
4610
4611
4612
4613
4614
4615
4616
4617
4618
4619
4620
4621
4622
4623
4624
4625
4626
4627
4628
4629
4630
4631
4632
4633
4634
4635
4636
4637
4638
4639
4640
4641
4642
4643
4644
4645
4646
4647
4648
4649
4650
4651
4652
4653
4654
4655
4656
4657
4658
4659
4660
4661
4662
4663
4664
4665
4666
4667
4668
4669
4670
4671
4672
4673
4674
4675
4676
4677
4678
4679
4680
4681
4682
4683
4684
4685
4686
4687
4688
4689
4690
4691
4692
4693
4694
4695
4696
4697
4698
4699
4700
4701
4702
4703
4704
4705
4706
4707
4708
4709
4710
4711
4712
4713
4714
4715
4716
4717
4718
4719
4720
4721
4722
4723
4724
4725
4726
4727
4728
4729
4730
4731
4732
4733
4734
4735
4736
4737
4738
4739
4740
4741
4742
4743
4744
4745
4746
4747
4748
4749
4750
4751
4752
4753
4754
4755
4756
4757
4758
4759
4760
4761
4762
4763
4764
4765
4766
4767
4768
4769
4770
4771
4772
4773
4774
4775
4776
4777
4778
4779
4780
4781
4782
4783
4784
4785
4786
4787
4788
4789
4790
4791
4792
4793
4794
4795
4796
4797
4798
4799
4800
4801
4802
4803
4804
4805
4806
4807
4808
4809
4810
4811
4812
4813
4814
4815
4816
4817
4818
4819
4820
4821
4822
4823
4824
4825
4826
4827
4828
4829
4830
4831
4832
4833
4834
4835
4836
4837
4838
4839
4840
4841
4842
4843
4844
4845
4846
4847
4848
4849
4850
4851
4852
4853
4854
4855
4856
4857
4858
4859
4860
4861
4862
4863
4864
4865
4866
4867
4868
4869
4870
4871
4872
4873
4874
4875
4876
4877
4878
4879
4880
4881
4882
4883
4884
4885
4886
4887
4888
4889
4890
4891
4892
4893
4894
4895
4896
4897
4898
4899
4900
4901
4902
4903
4904
4905
4906
4907
4908
4909
4910
4911
4912
4913
4914
4915
4916
4917
4918
4919
4920
4921
4922
4923
4924
4925
4926
4927
4928
4929
4930
4931
4932
4933
4934
4935
4936
4937
4938
4939
4940
4941
4942
4943
4944
4945
4946
4947
4948
4949
4950
4951
4952
4953
4954
4955
4956
4957
4958
4959
4960
4961
4962
4963
4964
4965
4966
4967
4968
4969
4970
4971
4972
4973
4974
4975
4976
4977
4978
4979
4980
4981
4982
4983
4984
4985
4986
4987
4988
4989
4990
4991
4992
4993
4994
4995
4996
4997
4998
4999
5000
5001
5002
5003
5004
5005
5006
5007
5008
5009
5010
5011
5012
5013
5014
5015
5016
5017
5018
5019
5020
5021
5022
5023
5024
5025
5026
5027
5028
5029
5030
5031
5032
5033
5034
5035
5036
5037
5038
5039
5040
5041
5042
5043
5044
5045
5046
5047
5048
5049
5050
5051
5052
5053
5054
5055
5056
5057
5058
5059
5060
5061
5062
5063
5064
5065
5066
5067
5068
5069
5070
5071
5072
5073
5074
5075
5076
5077
5078
5079
5080
5081
5082
5083
5084
5085
5086
5087
5088
5089
5090
5091
5092
5093
5094
5095
5096
5097
5098
5099
5100
5101
5102
5103
5104
5105
5106
5107
5108
5109
5110
5111
5112
5113
5114
5115
5116
5117
5118
5119
5120
5121
5122
5123
5124
5125
5126
5127
5128
5129
5130
5131
5132
5133
5134
5135
5136
5137
5138
5139
5140
5141
5142
5143
5144
5145
5146
5147
5148
5149
5150
5151
5152
5153
5154
5155
5156
5157
5158
5159
5160
5161
5162
5163
5164
5165
5166
5167
5168
5169
5170
5171
5172
5173
5174
5175
5176
5177
5178
5179
5180
5181
5182
5183
5184
5185
5186
5187
5188
5189
5190
5191
5192
5193
5194
5195
5196
5197
5198
5199
5200
5201
5202
5203
5204
5205
5206
5207
5208
5209
5210
5211
5212
5213
5214
5215
5216
5217
5218
5219
5220
5221
5222
5223
5224
5225
5226
5227
5228
5229
5230
5231
5232
5233
5234
5235
5236
5237
5238
5239
5240
5241
5242
5243
5244
5245
5246
5247
5248
5249
5250
5251
5252
5253
5254
5255
5256
5257
5258
5259
5260
5261
5262
5263
5264
5265
5266
5267
5268
5269
5270
5271
5272
5273
5274
5275
5276
5277
5278
5279
5280
5281
5282
5283
5284
5285
5286
5287
5288
5289
5290
5291
5292
5293
5294
5295
5296
5297
5298
5299
5300
5301
5302
5303
5304
5305
5306
5307
5308
5309
5310
5311
5312
5313
5314
5315
5316
5317
5318
5319
5320
5321
5322
5323
5324
5325
5326
5327
5328
5329
5330
5331
5332
5333
5334
5335
5336
5337
5338
5339
5340
5341
5342
5343
5344
5345
5346
5347
5348
5349
5350
5351
5352
5353
5354
5355
5356
5357
5358
5359
5360
5361
5362
5363
5364
5365
5366
5367
5368
5369
5370
5371
5372
5373
5374
5375
5376
5377
5378
5379
5380
5381
5382
5383
5384
5385
5386
5387
5388
5389
5390
5391
5392
5393
5394
5395
5396
5397
5398
5399
5400
5401
5402
5403
5404
5405
5406
5407
5408
5409
5410
5411
5412
5413
5414
5415
5416
5417
5418
5419
5420
5421
5422
5423
5424
5425
5426
5427
5428
5429
5430
5431
5432
5433
5434
5435
5436
5437
5438
5439
5440
5441
5442
5443
5444
5445
5446
5447
5448
5449
5450
5451
5452
5453
5454
5455
5456
5457
5458
5459
5460
5461
5462
5463
5464
5465
5466
5467
5468
5469
5470
5471
5472
5473
5474
5475
5476
5477
5478
5479
5480
5481
5482
5483
5484
5485
5486
5487
5488
5489
5490
5491
5492
5493
5494
5495
5496
5497
5498
5499
5500
5501
5502
5503
5504
5505
5506
5507
5508
5509
5510
5511
5512
5513
5514
5515
5516
5517
5518
5519
5520
5521
5522
5523
5524
5525
5526
5527
5528
5529
5530
5531
5532
5533
5534
5535
5536
5537
5538
5539
5540
5541
5542
5543
5544
5545
5546
5547
5548
5549
5550
5551
5552
5553
5554
5555
5556
5557
5558
5559
5560
5561
5562
5563
5564
5565
5566
5567
5568
5569
5570
5571
5572
5573
5574
5575
5576
5577
5578
5579
5580
5581
5582
5583
5584
5585
5586
5587
5588
5589
5590
5591
5592
5593
5594
5595
5596
5597
5598
5599
5600
5601
5602
5603
5604
5605
5606
5607
5608
5609
5610
5611
5612
5613
5614
5615
5616
5617
5618
5619
5620
5621
5622
5623
5624
5625
5626
5627
5628
5629
5630
5631
5632
5633
5634
5635
5636
5637
5638
5639
5640
5641
5642
5643
5644
5645
5646
5647
5648
5649
5650
5651
5652
5653
5654
5655
5656
5657
5658
5659
5660
5661
5662
5663
5664
5665
5666
5667
5668
5669
5670
5671
5672
5673
5674
5675
5676
5677
5678
5679
5680
5681
5682
5683
5684
5685
5686
5687
5688
5689
5690
5691
5692
5693
5694
5695
5696
5697
5698
5699
5700
5701
5702
5703
5704
5705
5706
5707
5708
5709
5710
5711
5712
5713
5714
5715
5716
5717
5718
5719
5720
5721
5722
5723
5724
5725
5726
5727
5728
5729
5730
5731
5732
5733
5734
5735
5736
5737
5738
5739
5740
5741
5742
5743
5744
5745
5746
5747
5748
5749
5750
5751
5752
5753
5754
5755
5756
5757
5758
5759
5760
5761
5762
5763
5764
5765
5766
5767
5768
5769
5770
5771
5772
5773
5774
5775
5776
5777
5778
5779
5780
5781
5782
5783
5784
5785
5786
5787
5788
5789
5790
5791
5792
5793
5794
5795
5796
5797
5798
5799
5800
5801
5802
5803
5804
5805
5806
5807
5808
5809
5810
5811
5812
5813
5814
5815
5816
5817
5818
5819
5820
5821
5822
5823
5824
5825
5826
5827
5828
5829
5830
5831
5832
5833
5834
5835
5836
5837
5838
5839
5840
5841
5842
5843
5844
5845
5846
5847
5848
5849
5850
5851
5852
5853
5854
5855
5856
5857
5858
5859
5860
5861
5862
5863
5864
5865
5866
5867
5868
5869
5870
5871
5872
5873
5874
5875
5876
5877
5878
5879
5880
5881
5882
5883
5884
5885
5886
5887
5888
5889
5890
5891
5892
5893
5894
5895
5896
5897
5898
5899
5900
5901
5902
5903
5904
5905
5906
5907
5908
5909
5910
5911
5912
5913
5914
5915
5916
5917
5918
5919
5920
5921
5922
5923
5924
5925
5926
5927
5928
5929
5930
5931
5932
5933
5934
5935
5936
5937
5938
5939
5940
5941
5942
5943
5944
5945
5946
5947
5948
5949
5950
5951
5952
5953
5954
5955
5956
5957
5958
5959
5960
5961
5962
5963
5964
5965
5966
5967
5968
5969
5970
5971
5972
5973
5974
5975
5976
5977
5978
5979
5980
5981
5982
5983
5984
5985
5986
5987
5988
5989
5990
5991
5992
5993
5994
5995
5996
5997
5998
5999
6000
6001
6002
6003
6004
6005
6006
6007
6008
6009
6010
6011
6012
6013
6014
6015
6016
6017
6018
6019
6020
6021
6022
6023
6024
6025
6026
6027
6028
6029
6030
6031
6032
6033
6034
6035
6036
6037
6038
6039
6040
6041
6042
6043
6044
6045
6046
6047
6048
6049
6050
6051
6052
6053
6054
6055
6056
6057
6058
6059
6060
6061
6062
6063
6064
6065
6066
6067
6068
6069
6070
6071
6072
6073
6074
6075
6076
6077
6078
6079
6080
6081
6082
6083
6084
6085
6086
6087
6088
6089
6090
6091
6092
6093
6094
6095
6096
6097
6098
6099
6100
6101
6102
6103
6104
6105
6106
6107
6108
6109
6110
6111
6112
6113
6114
6115
6116
6117
6118
6119
6120
6121
6122
6123
6124
6125
6126
6127
6128
6129
6130
6131
6132
6133
6134
6135
6136
6137
6138
6139
6140
6141
6142
6143
6144
6145
6146
6147
6148
6149
6150
6151
6152
6153
6154
6155
6156
6157
6158
6159
6160
6161
6162
6163
6164
6165
6166
6167
6168
6169
6170
6171
6172
6173
6174
6175
6176
6177
6178
6179
6180
6181
6182
6183
6184
6185
6186
6187
6188
6189
6190
6191
6192
6193
6194
6195
6196
6197
6198
6199
6200
6201
6202
6203
6204
6205
6206
6207
6208
6209
6210
6211
6212
6213
6214
6215
6216
6217
6218
6219
6220
6221
6222
6223
6224
6225
6226
6227
6228
6229
6230
6231
6232
6233
6234
6235
6236
6237
6238
6239
6240
6241
6242
6243
6244
6245
6246
6247
6248
6249
6250
6251
6252
6253
6254
6255
6256
6257
6258
6259
6260
6261
6262
6263
6264
6265
6266
6267
6268
6269
6270
6271
6272
6273
6274
6275
6276
6277
6278
6279
6280
6281
6282
6283
6284
6285
6286
6287
6288
6289
6290
6291
6292
6293
6294
6295
6296
6297
6298
6299
6300
6301
6302
6303
6304
6305
6306
6307
6308
6309
6310
6311
6312
6313
6314
6315
6316
6317
6318
6319
6320
6321
6322
6323
6324
6325
6326
6327
6328
6329
6330
6331
6332
6333
6334
6335
6336
6337
6338
6339
6340
6341
6342
6343
6344
6345
6346
6347
6348
6349
6350
6351
6352
6353
6354
6355
6356
6357
6358
6359
6360
6361
6362
6363
6364
6365
6366
6367
6368
6369
6370
6371
6372
6373
6374
6375
6376
6377
6378
6379
6380
6381
6382
6383
6384
6385
6386
6387
6388
6389
6390
6391
6392
6393
6394
6395
6396
6397
6398
6399
6400
6401
6402
6403
6404
6405
6406
6407
6408
6409
6410
6411
6412
6413
6414
6415
6416
6417
6418
6419
6420
6421
6422
6423
6424
6425
6426
6427
6428
6429
6430
6431
6432
6433
6434
6435
6436
6437
6438
6439
6440
6441
6442
6443
6444
6445
6446
6447
6448
6449
6450
6451
6452
6453
6454
6455
6456
6457
6458
6459
6460
6461
6462
6463
6464
6465
6466
6467
6468
6469
6470
6471
6472
6473
6474
6475
6476
6477
6478
6479
6480
6481
6482
6483
6484
6485
6486
6487
6488
6489
6490
6491
6492
6493
6494
6495
6496
6497
6498
6499
6500
6501
6502
6503
6504
6505
6506
6507
6508
6509
6510
6511
6512
6513
6514
6515
6516
6517
6518
6519
6520
6521
6522
6523
6524
6525
6526
6527
6528
6529
6530
6531
6532
6533
6534
6535
6536
6537
6538
6539
6540
6541
6542
6543
6544
6545
6546
6547
6548
6549
6550
6551
6552
6553
6554
6555
6556
6557
6558
6559
6560
6561
6562
6563
6564
6565
6566
6567
6568
6569
6570
6571
6572
6573
6574
6575
6576
6577
6578
6579
6580
6581
6582
6583
6584
6585
6586
6587
6588
6589
6590
6591
6592
6593
6594
6595
6596
6597
6598
6599
6600
6601
6602
6603
6604
6605
6606
6607
6608
6609
6610
6611
6612
6613
6614
6615
6616
6617
6618
6619
6620
6621
6622
6623
6624
6625
6626
6627
6628
6629
6630
6631
6632
6633
6634
6635
6636
6637
6638
6639
6640
6641
6642
6643
6644
6645
6646
6647
6648
6649
6650
6651
6652
6653
6654
6655
6656
6657
6658
6659
6660
6661
6662
6663
6664
6665
6666
6667
6668
6669
6670
6671
6672
6673
6674
6675
6676
6677
6678
6679
6680
6681
6682
6683
6684
6685
6686
6687
6688
6689
6690
6691
6692
6693
6694
6695
6696
6697
6698
6699
6700
6701
6702
6703
6704
6705
6706
6707
6708
6709
6710
6711
6712
6713
6714
6715
6716
6717
6718
6719
6720
6721
6722
6723
6724
6725
6726
6727
6728
6729
6730
6731
6732
6733
6734
6735
6736
6737
6738
6739
6740
6741
6742
6743
6744
6745
6746
6747
6748
6749
6750
6751
6752
6753
6754
6755
6756
6757
6758
6759
6760
6761
6762
6763
6764
6765
6766
6767
6768
6769
6770
6771
6772
6773
6774
6775
6776
6777
6778
6779
6780
6781
6782
6783
6784
6785
6786
6787
6788
6789
6790
6791
6792
6793
6794
6795
6796
6797
6798
6799
6800
6801
6802
6803
6804
6805
6806
6807
6808
6809
6810
6811
6812
6813
6814
6815
6816
6817
6818
6819
6820
6821
6822
6823
6824
6825
6826
6827
6828
6829
6830
6831
6832
6833
6834
6835
6836
6837
6838
6839
6840
6841
6842
6843
6844
6845
6846
6847
6848
6849
6850
6851
6852
6853
6854
6855
6856
6857
6858
6859
6860
6861
6862
6863
6864
6865
6866
6867
6868
6869
6870
6871
6872
6873
6874
6875
6876
6877
6878
6879
6880
6881
6882
6883
6884
6885
6886
6887
6888
6889
6890
6891
6892
6893
6894
6895
6896
6897
6898
6899
6900
6901
6902
6903
6904
6905
6906
6907
6908
6909
6910
6911
6912
6913
6914
6915
6916
6917
6918
6919
6920
6921
6922
6923
6924
6925
6926
6927
6928
6929
6930
6931
6932
6933
6934
6935
6936
6937
6938
6939
6940
6941
6942
6943
6944
6945
6946
6947
6948
6949
6950
6951
6952
6953
6954
6955
6956
6957
6958
6959
6960
6961
6962
6963
6964
6965
6966
6967
6968
6969
6970
6971
6972
6973
6974
6975
6976
6977
6978
6979
6980
6981
6982
6983
6984
6985
6986
6987
6988
6989
6990
6991
6992
6993
6994
6995
6996
6997
6998
6999
7000
7001
7002
7003
7004
7005
7006
7007
7008
7009
7010
7011
7012
7013
7014
7015
7016
7017
7018
7019
7020
7021
7022
7023
7024
7025
7026
7027
7028
7029
7030
7031
7032
7033
7034
7035
7036
7037
7038
7039
7040
7041
7042
7043
7044
7045
7046
7047
7048
7049
7050
7051
7052
7053
7054
7055
7056
7057
7058
7059
7060
7061
7062
7063
7064
7065
7066
7067
7068
7069
7070
7071
7072
7073
7074
7075
7076
7077
7078
7079
7080
7081
7082
7083
7084
7085
7086
7087
7088
7089
7090
7091
7092
7093
7094
7095
7096
7097
7098
7099
7100
7101
7102
7103
7104
7105
7106
7107
7108
7109
7110
7111
7112
7113
7114
7115
7116
7117
7118
7119
7120
7121
7122
7123
7124
7125
7126
7127
7128
7129
7130
7131
7132
7133
7134
7135
7136
7137
7138
7139
7140
7141
7142
7143
7144
7145
7146
7147
7148
7149
7150
7151
7152
7153
7154
7155
7156
7157
7158
7159
7160
7161
7162
7163
7164
7165
7166
7167
7168
7169
7170
7171
7172
7173
7174
7175
7176
7177
7178
7179
7180
7181
7182
7183
7184
7185
7186
7187
7188
7189
7190
7191
7192
7193
7194
7195
7196
7197
7198
7199
7200
7201
7202
7203
7204
7205
7206
7207
7208
7209
7210
7211
7212
7213
7214
7215
7216
7217
7218
7219
7220
7221
7222
7223
7224
7225
7226
7227
7228
7229
7230
7231
7232
7233
7234
7235
7236
7237
7238
7239
7240
7241
7242
7243
7244
7245
7246
7247
7248
7249
7250
7251
7252
7253
7254
7255
7256
7257
7258
7259
7260
7261
7262
7263
7264
7265
7266
7267
7268
7269
7270
7271
7272
7273
7274
7275
7276
7277
7278
7279
7280
7281
7282
7283
7284
7285
7286
7287
7288
7289
7290
7291
7292
7293
7294
7295
7296
7297
7298
7299
7300
7301
7302
7303
7304
7305
7306
7307
7308
7309
7310
7311
7312
7313
7314
7315
7316
7317
7318
7319
7320
7321
7322
7323
7324
7325
7326
7327
7328
7329
7330
7331
7332
7333
7334
7335
7336
7337
7338
7339
7340
7341
7342
7343
7344
7345
7346
7347
7348
7349
7350
7351
7352
7353
7354
7355
7356
7357
7358
7359
7360
7361
7362
7363
7364
7365
7366
7367
7368
7369
7370
7371
7372
7373
7374
7375
7376
7377
7378
7379
7380
7381
7382
7383
7384
7385
7386
7387
7388
7389
7390
7391
7392
7393
7394
7395
7396
7397
7398
7399
7400
7401
7402
7403
7404
7405
7406
7407
7408
7409
7410
7411
7412
7413
7414
7415
7416
7417
7418
7419
7420
7421
7422
7423
7424
7425
7426
7427
7428
7429
7430
7431
7432
7433
7434
7435
7436
7437
7438
7439
7440
7441
7442
7443
7444
7445
7446
7447
7448
7449
7450
7451
7452
7453
7454
7455
7456
7457
7458
7459
7460
7461
7462
7463
7464
7465
7466
7467
7468
7469
7470
7471
7472
7473
7474
7475
7476
7477
7478
7479
7480
7481
7482
7483
7484
7485
7486
7487
7488
7489
7490
7491
7492
7493
7494
7495
7496
7497
7498
7499
7500
7501
7502
7503
7504
7505
7506
7507
7508
7509
7510
7511
7512
7513
7514
7515
7516
7517
7518
7519
7520
7521
7522
7523
7524
7525
7526
7527
7528
7529
7530
7531
7532
7533
7534
7535
7536
7537
7538
7539
7540
7541
7542
7543
7544
7545
7546
7547
7548
7549
7550
7551
7552
7553
7554
7555
7556
7557
7558
7559
7560
7561
7562
7563
7564
7565
7566
7567
7568
7569
7570
7571
7572
7573
7574
7575
7576
7577
7578
7579
7580
7581
7582
7583
7584
7585
7586
7587
7588
7589
7590
7591
7592
7593
7594
7595
7596
7597
7598
7599
7600
7601
7602
7603
7604
7605
7606
7607
7608
7609
7610
7611
7612
7613
7614
7615
7616
7617
7618
7619
7620
7621
7622
7623
7624
7625
7626
7627
7628
7629
7630
7631
7632
7633
7634
7635
7636
7637
7638
7639
7640
7641
7642
7643
7644
7645
7646
7647
7648
7649
7650
7651
7652
7653
7654
7655
7656
7657
7658
7659
7660
7661
7662
7663
7664
7665
7666
7667
7668
7669
7670
7671
7672
7673
7674
7675
7676
7677
7678
7679
7680
7681
7682
7683
7684
7685
7686
7687
7688
7689
7690
7691
7692
7693
7694
7695
7696
7697
7698
7699
7700
7701
7702
7703
7704
7705
7706
7707
7708
7709
7710
7711
7712
7713
7714
7715
7716
7717
7718
7719
7720
7721
7722
7723
7724
7725
7726
7727
7728
7729
7730
7731
7732
7733
7734
7735
7736
7737
7738
7739
7740
7741
7742
7743
7744
7745
7746
7747
7748
7749
7750
7751
7752
7753
7754
7755
7756
7757
7758
7759
7760
7761
7762
7763
7764
7765
7766
7767
7768
7769
7770
7771
7772
7773
7774
7775
7776
7777
7778
7779
7780
7781
7782
7783
7784
7785
7786
7787
7788
7789
7790
7791
7792
7793
7794
7795
7796
7797
7798
7799
7800
7801
7802
7803
7804
7805
7806
7807
7808
7809
7810
7811
7812
7813
7814
7815
7816
7817
7818
7819
7820
7821
7822
7823
7824
7825
7826
7827
7828
7829
7830
7831
7832
7833
7834
7835
7836
7837
7838
7839
7840
7841
7842
7843
7844
7845
7846
7847
7848
7849
7850
7851
7852
7853
7854
7855
7856
7857
7858
7859
7860
7861
7862
7863
7864
7865
7866
7867
7868
7869
7870
7871
7872
7873
7874
7875
7876
7877
7878
7879
7880
7881
7882
7883
7884
7885
7886
7887
7888
7889
7890
7891
7892
7893
7894
7895
7896
7897
7898
7899
7900
7901
7902
7903
7904
7905
7906
7907
7908
7909
7910
7911
7912
7913
7914
7915
7916
7917
7918
7919
7920
7921
7922
7923
7924
7925
7926
7927
7928
7929
7930
7931
7932
7933
7934
7935
7936
7937
7938
7939
7940
7941
7942
7943
7944
7945
7946
7947
7948
7949
7950
7951
7952
7953
7954
7955
7956
7957
7958
7959
7960
7961
7962
7963
7964
7965
7966
7967
7968
7969
7970
7971
7972
7973
7974
7975
7976
7977
7978
7979
7980
7981
7982
7983
7984
7985
7986
7987
7988
7989
7990
7991
7992
7993
7994
7995
7996
7997
7998
7999
8000
8001
8002
8003
8004
8005
8006
8007
8008
8009
8010
8011
8012
8013
8014
8015
8016
8017
8018
8019
8020
8021
8022
8023
8024
8025
8026
8027
8028
8029
8030
8031
8032
8033
8034
8035
8036
8037
8038
8039
8040
8041
8042
8043
8044
8045
8046
8047
8048
8049
8050
8051
8052
8053
8054
8055
8056
8057
8058
8059
8060
8061
8062
8063
8064
8065
8066
8067
8068
8069
8070
8071
8072
8073
8074
8075
8076
8077
8078
8079
8080
8081
8082
8083
8084
8085
8086
8087
8088
8089
8090
8091
8092
8093
8094
8095
8096
8097
8098
8099
8100
8101
8102
8103
8104
8105
8106
8107
8108
8109
8110
8111
8112
8113
8114
8115
8116
8117
8118
8119
8120
8121
8122
8123
8124
8125
8126
8127
8128
8129
8130
8131
8132
8133
8134
8135
8136
8137
8138
8139
8140
8141
8142
8143
8144
8145
8146
8147
8148
8149
8150
8151
8152
8153
8154
8155
8156
8157
8158
8159
8160
8161
8162
8163
8164
8165
8166
8167
8168
8169
8170
8171
8172
8173
8174
8175
8176
8177
8178
8179
8180
8181
8182
8183
8184
8185
8186
8187
8188
8189
8190
8191
8192
8193
8194
8195
8196
8197
8198
8199
8200
8201
8202
8203
8204
8205
8206
8207
8208
8209
8210
8211
8212
8213
8214
8215
8216
8217
8218
8219
8220
8221
8222
8223
8224
8225
8226
8227
8228
8229
8230
8231
8232
8233
8234
8235
8236
8237
8238
8239
8240
8241
8242
8243
8244
8245
8246
8247
8248
8249
8250
8251
8252
8253
8254
8255
8256
8257
8258
8259
8260
8261
8262
8263
8264
8265
8266
8267
8268
8269
8270
8271
8272
8273
8274
8275
8276
8277
8278
8279
8280
8281
8282
8283
8284
8285
8286
8287
8288
8289
8290
8291
8292
8293
8294
8295
8296
8297
8298
8299
8300
8301
8302
8303
8304
8305
8306
8307
8308
8309
8310
8311
8312
8313
8314
8315
8316
8317
8318
8319
8320
8321
8322
8323
8324
8325
8326
8327
8328
8329
8330
8331
8332
8333
8334
8335
8336
8337
8338
8339
8340
8341
8342
8343
8344
8345
8346
8347
8348
8349
8350
8351
8352
8353
8354
8355
8356
8357
8358
8359
8360
8361
8362
8363
8364
8365
8366
8367
8368
8369
8370
8371
8372
8373
8374
8375
8376
8377
8378
8379
8380
8381
8382
8383
8384
8385
8386
8387
8388
8389
8390
8391
8392
8393
8394
8395
8396
8397
8398
8399
8400
8401
8402
8403
8404
8405
8406
8407
8408
8409
8410
8411
8412
8413
8414
8415
8416
8417
8418
8419
8420
8421
8422
8423
8424
8425
8426
8427
8428
8429
8430
8431
8432
8433
8434
8435
8436
8437
8438
8439
8440
8441
8442
8443
8444
8445
8446
8447
8448
8449
8450
8451
8452
8453
8454
8455
8456
8457
8458
8459
8460
8461
8462
8463
8464
8465
8466
8467
8468
8469
8470
8471
8472
8473
8474
8475
8476
8477
8478
8479
8480
8481
8482
8483
8484
8485
8486
8487
8488
8489
8490
8491
8492
8493
8494
8495
8496
8497
8498
8499
8500
8501
8502
8503
8504
8505
8506
8507
8508
8509
8510
8511
8512
8513
8514
8515
8516
8517
8518
8519
8520
8521
8522
8523
8524
8525
8526
8527
8528
8529
8530
8531
8532
8533
8534
8535
8536
8537
8538
8539
8540
8541
8542
8543
8544
8545
8546
8547
8548
8549
8550
8551
8552
8553
8554
8555
8556
8557
8558
8559
8560
8561
8562
8563
8564
8565
8566
8567
8568
8569
8570
8571
8572
8573
8574
8575
8576
8577
8578
8579
8580
8581
8582
8583
8584
8585
8586
8587
8588
8589
8590
8591
8592
8593
8594
8595
8596
8597
8598
8599
8600
8601
8602
8603
8604
8605
8606
8607
8608
8609
8610
8611
8612
8613
8614
8615
8616
8617
8618
8619
8620
8621
8622
8623
8624
8625
8626
8627
8628
8629
8630
8631
8632
8633
8634
8635
8636
8637
8638
8639
8640
8641
8642
8643
8644
8645
8646
8647
8648
8649
8650
8651
8652
8653
8654
8655
8656
8657
8658
8659
8660
8661
8662
8663
8664
8665
8666
8667
8668
8669
8670
8671
8672
8673
8674
8675
8676
8677
8678
8679
8680
8681
8682
8683
8684
8685
8686
8687
8688
8689
8690
8691
8692
8693
8694
8695
8696
8697
8698
8699
8700
8701
8702
8703
8704
8705
8706
8707
8708
8709
8710
8711
8712
8713
8714
8715
8716
8717
8718
8719
8720
8721
8722
8723
8724
8725
8726
8727
8728
8729
8730
8731
8732
8733
8734
8735
8736
8737
8738
8739
8740
8741
8742
8743
8744
8745
8746
8747
8748
8749
8750
8751
8752
8753
8754
8755
8756
8757
8758
8759
8760
8761
8762
8763
8764
8765
8766
8767
8768
8769
8770
8771
8772
8773
8774
8775
8776
8777
8778
8779
8780
8781
8782
8783
8784
8785
8786
8787
8788
8789
8790
8791
8792
8793
8794
8795
8796
8797
8798
8799
8800
8801
8802
8803
8804
8805
8806
8807
8808
8809
8810
8811
8812
8813
8814
8815
8816
8817
8818
8819
8820
8821
8822
8823
8824
8825
8826
8827
8828
8829
8830
8831
8832
8833
8834
8835
8836
8837
8838
8839
8840
8841
8842
8843
8844
8845
8846
8847
8848
8849
8850
8851
8852
8853
8854
8855
8856
8857
8858
8859
8860
8861
8862
8863
8864
8865
8866
8867
8868
8869
8870
8871
8872
8873
8874
8875
8876
8877
8878
8879
8880
8881
8882
8883
8884
8885
8886
8887
8888
8889
8890
8891
8892
8893
8894
8895
8896
8897
8898
8899
8900
8901
8902
8903
8904
8905
8906
8907
8908
8909
8910
8911
8912
8913
8914
8915
8916
8917
8918
8919
8920
8921
8922
8923
8924
8925
8926
8927
8928
8929
8930
8931
8932
8933
8934
8935
8936
8937
8938
8939
8940
8941
8942
8943
8944
8945
8946
8947
8948
8949
8950
8951
8952
8953
8954
8955
8956
8957
8958
8959
8960
8961
8962
8963
8964
8965
8966
8967
8968
8969
8970
8971
8972
8973
8974
8975
8976
8977
8978
8979
8980
8981
8982
8983
8984
8985
8986
8987
8988
8989
8990
8991
8992
8993
8994
8995
8996
8997
8998
8999
9000
9001
9002
9003
9004
9005
9006
9007
9008
9009
9010
9011
9012
9013
9014
9015
9016
9017
9018
9019
9020
9021
9022
9023
9024
9025
9026
9027
9028
9029
9030
9031
9032
9033
9034
9035
9036
9037
9038
9039
9040
9041
9042
9043
9044
9045
9046
9047
9048
9049
9050
9051
9052
9053
9054
9055
9056
9057
9058
9059
9060
9061
9062
9063
9064
9065
9066
9067
9068
9069
9070
9071
9072
9073
9074
9075
9076
9077
9078
9079
9080
9081
9082
9083
9084
9085
9086
9087
9088
9089
9090
9091
9092
9093
9094
9095
9096
9097
9098
9099
9100
9101
9102
9103
9104
9105
9106
9107
9108
9109
9110
9111
9112
9113
9114
9115
9116
9117
9118
9119
9120
9121
9122
9123
9124
9125
9126
9127
9128
9129
9130
9131
9132
9133
9134
9135
9136
9137
9138
9139
9140
9141
9142
9143
9144
9145
9146
9147
9148
9149
9150
9151
9152
9153
9154
9155
9156
9157
9158
9159
9160
9161
9162
9163
9164
9165
9166
9167
9168
9169
9170
9171
9172
9173
9174
9175
9176
9177
9178
9179
9180
9181
9182
9183
9184
9185
9186
9187
9188
9189
9190
9191
9192
9193
9194
9195
9196
9197
9198
9199
9200
9201
9202
9203
9204
9205
9206
9207
9208
9209
9210
9211
9212
9213
9214
9215
9216
9217
9218
9219
9220
9221
9222
9223
9224
9225
9226
9227
9228
9229
9230
9231
9232
9233
9234
9235
9236
9237
9238
9239
9240
9241
9242
9243
9244
9245
9246
9247
9248
9249
9250
9251
9252
9253
9254
9255
9256
9257
9258
9259
9260
9261
9262
9263
9264
9265
9266
9267
9268
9269
9270
9271
9272
9273
9274
9275
9276
9277
9278
9279
9280
9281
9282
9283
9284
9285
9286
9287
9288
9289
9290
9291
9292
9293
9294
9295
9296
9297
9298
9299
9300
9301
9302
9303
9304
9305
9306
9307
9308
9309
9310
9311
9312
9313
9314
9315
9316
9317
9318
9319
9320
9321
9322
9323
9324
9325
9326
9327
9328
9329
9330
9331
9332
9333
9334
9335
9336
9337
9338
9339
9340
9341
9342
9343
9344
9345
9346
9347
9348
9349
9350
9351
9352
9353
9354
9355
9356
9357
9358
9359
9360
9361
9362
9363
9364
9365
9366
9367
9368
9369
9370
9371
9372
9373
9374
9375
9376
9377
9378
9379
9380
9381
9382
9383
9384
9385
9386
9387
9388
9389
9390
9391
9392
9393
9394
9395
9396
9397
9398
9399
9400
9401
9402
9403
9404
9405
9406
9407
9408
9409
9410
9411
9412
9413
9414
9415
9416
9417
9418
9419
9420
9421
9422
9423
9424
9425
9426
9427
9428
9429
9430
9431
9432
9433
9434
9435
9436
9437
9438
9439
9440
9441
9442
9443
9444
9445
9446
9447
9448
9449
9450
9451
9452
9453
9454
9455
9456
9457
9458
9459
9460
9461
9462
9463
9464
9465
9466
9467
9468
9469
9470
9471
9472
9473
9474
9475
9476
9477
9478
9479
9480
9481
9482
9483
9484
9485
9486
9487
9488
9489
9490
9491
9492
9493
9494
9495
9496
9497
9498
9499
9500
9501
9502
9503
9504
9505
9506
9507
9508
9509
9510
9511
9512
9513
9514
9515
9516
9517
9518
9519
9520
9521
9522
9523
9524
9525
9526
9527
9528
9529
9530
9531
9532
9533
9534
9535
9536
9537
9538
9539
9540
9541
9542
9543
9544
9545
9546
9547
9548
9549
9550
9551
9552
9553
9554
9555
9556
9557
9558
9559
9560
9561
9562
9563
9564
9565
9566
9567
9568
9569
9570
9571
9572
9573
9574
9575
9576
9577
9578
9579
9580
9581
9582
9583
9584
9585
9586
9587
9588
9589
9590
9591
9592
9593
9594
9595
9596
9597
9598
9599
9600
9601
9602
9603
9604
9605
9606
9607
9608
9609
9610
9611
9612
9613
9614
9615
9616
9617
9618
9619
9620
9621
9622
9623
9624
9625
9626
9627
9628
9629
9630
9631
9632
9633
9634
9635
9636
9637
9638
9639
9640
9641
9642
9643
9644
9645
9646
9647
9648
9649
9650
9651
9652
9653
9654
9655
9656
9657
9658
9659
9660
9661
9662
9663
9664
9665
9666
9667
9668
9669
9670
9671
9672
9673
9674
9675
9676
9677
9678
9679
9680
9681
9682
9683
9684
9685
9686
9687
9688
9689
9690
9691
9692
9693
9694
9695
9696
9697
9698
9699
9700
9701
9702
9703
9704
9705
9706
9707
9708
9709
9710
9711
9712
9713
9714
9715
9716
9717
9718
9719
9720
9721
9722
9723
9724
9725
9726
9727
9728
9729
9730
9731
9732
9733
9734
9735
9736
9737
9738
9739
9740
9741
9742
9743
9744
9745
9746
9747
9748
9749
9750
9751
9752
9753
9754
9755
9756
9757
9758
9759
9760
9761
9762
9763
9764
9765
9766
9767
9768
9769
9770
9771
9772
9773
9774
9775
9776
9777
9778
9779
9780
9781
9782
9783
9784
9785
9786
9787
9788
9789
9790
9791
9792
9793
9794
9795
9796
9797
9798
9799
9800
9801
9802
9803
9804
9805
9806
9807
9808
9809
9810
9811
9812
9813
9814
9815
9816
9817
9818
9819
9820
9821
9822
9823
9824
9825
9826
9827
9828
9829
9830
9831
9832
9833
9834
9835
9836
9837
9838
9839
9840
9841
9842
9843
9844
9845
9846
9847
9848
9849
9850
9851
9852
9853
9854
9855
9856
9857
9858
9859
9860
9861
9862
9863
9864
9865
9866
9867
9868
9869
9870
9871
9872
9873
9874
9875
9876
9877
9878
9879
9880
9881
9882
9883
9884
9885
9886
9887
9888
9889
9890
9891
9892
9893
9894
9895
9896
9897
9898
9899
9900
9901
9902
9903
9904
9905
9906
9907
9908
9909
9910
9911
9912
9913
9914
9915
9916
9917
9918
9919
9920
9921
9922
9923
9924
9925
9926
9927
9928
9929
9930
9931
9932
9933
9934
9935
9936
9937
9938
9939
9940
9941
9942
9943
9944
9945
9946
9947
9948
9949
9950
9951
9952
9953
9954
9955
9956
9957
9958
9959
9960
9961
9962
9963
9964
9965
9966
9967
9968
9969
9970
9971
9972
9973
9974
9975
9976
9977
9978
9979
9980
9981
9982
9983
9984
9985
9986
9987
9988
9989
9990
9991
9992
9993
9994
9995
9996
9997
9998
9999
10000
10001
10002
10003
10004
10005
10006
10007
10008
10009
10010
10011
10012
10013
10014
10015
10016
10017
10018
10019
10020
10021
10022
10023
10024
10025
10026
10027
10028
10029
10030
10031
10032
10033
10034
10035
10036
10037
10038
10039
10040
10041
10042
10043
10044
10045
10046
10047
10048
10049
10050
10051
10052
10053
10054
10055
10056
10057
10058
10059
10060
10061
10062
10063
10064
10065
10066
10067
10068
10069
10070
10071
10072
10073
10074
10075
10076
10077
10078
10079
10080
10081
10082
10083
10084
10085
10086
10087
10088
10089
10090
10091
10092
10093
10094
10095
10096
10097
10098
10099
10100
10101
10102
10103
10104
10105
10106
10107
10108
10109
10110
10111
10112
10113
10114
10115
10116
10117
10118
10119
10120
10121
10122
10123
10124
10125
10126
10127
10128
10129
10130
10131
10132
10133
10134
10135
10136
10137
10138
10139
10140
10141
10142
10143
10144
10145
10146
10147
10148
10149
10150
10151
10152
10153
10154
10155
10156
10157
10158
10159
10160
10161
10162
10163
10164
10165
10166
10167
10168
10169
10170
10171
10172
10173
10174
10175
10176
10177
10178
10179
10180
10181
10182
10183
10184
10185
10186
10187
10188
10189
10190
10191
10192
10193
10194
10195
10196
10197
10198
10199
10200
10201
10202
10203
10204
10205
10206
10207
10208
10209
10210
10211
10212
10213
10214
10215
10216
10217
10218
10219
10220
10221
10222
10223
10224
10225
10226
10227
10228
10229
10230
10231
10232
10233
10234
10235
10236
10237
10238
10239
10240
10241
10242
10243
10244
10245
10246
10247
10248
10249
10250
10251
10252
10253
10254
10255
10256
10257
10258
10259
10260
10261
10262
10263
10264
10265
10266
10267
10268
10269
10270
10271
10272
10273
10274
10275
10276
10277
10278
10279
10280
10281
10282
10283
10284
10285
10286
10287
10288
10289
10290
10291
10292
10293
10294
10295
10296
10297
10298
10299
10300
10301
10302
10303
10304
10305
10306
10307
10308
10309
10310
10311
10312
10313
10314
10315
10316
10317
10318
10319
10320
10321
10322
10323
10324
10325
10326
10327
10328
10329
10330
10331
10332
10333
10334
10335
10336
10337
10338
10339
10340
10341
10342
10343
10344
10345
10346
10347
10348
10349
10350
10351
10352
10353
10354
10355
10356
10357
10358
10359
10360
10361
10362
10363
10364
10365
10366
10367
10368
10369
10370
10371
10372
10373
10374
10375
10376
10377
10378
10379
10380
10381
10382
10383
10384
10385
10386
10387
10388
10389
10390
10391
10392
10393
10394
10395
10396
10397
10398
10399
10400
10401
10402
10403
10404
10405
10406
10407
10408
10409
10410
10411
10412
10413
10414
10415
10416
10417
10418
10419
10420
10421
10422
10423
10424
10425
10426
10427
10428
10429
10430
10431
10432
10433
10434
10435
10436
10437
10438
10439
10440
10441
10442
10443
10444
10445
10446
10447
10448
10449
10450
10451
10452
10453
10454
10455
10456
10457
10458
10459
10460
10461
10462
10463
10464
10465
10466
10467
10468
10469
10470
10471
10472
10473
10474
10475
10476
10477
10478
10479
10480
10481
10482
10483
10484
10485
10486
10487
10488
10489
10490
10491
10492
10493
10494
10495
10496
10497
10498
10499
10500
10501
10502
10503
10504
10505
10506
10507
10508
10509
10510
10511
10512
10513
10514
10515
10516
10517
10518
10519
10520
10521
10522
10523
10524
10525
10526
10527
10528
10529
10530
10531
10532
10533
10534
10535
10536
10537
10538
10539
10540
10541
10542
10543
10544
10545
10546
10547
10548
10549
10550
10551
10552
10553
10554
10555
10556
10557
10558
10559
10560
10561
10562
10563
10564
10565
10566
10567
10568
10569
10570
10571
10572
10573
10574
10575
10576
10577
10578
10579
10580
10581
10582
10583
10584
10585
10586
10587
10588
10589
10590
10591
10592
10593
10594
10595
10596
10597
10598
10599
10600
10601
10602
10603
10604
10605
10606
10607
10608
10609
10610
10611
10612
10613
10614
10615
10616
10617
10618
10619
10620
10621
10622
10623
10624
10625
10626
10627
10628
10629
10630
10631
10632
10633
10634
10635
10636
10637
10638
10639
10640
10641
10642
10643
10644
10645
10646
10647
10648
10649
10650
10651
10652
10653
10654
10655
10656
10657
10658
10659
10660
10661
10662
10663
10664
10665
10666
10667
10668
10669
10670
10671
10672
10673
10674
10675
10676
10677
10678
10679
10680
10681
10682
10683
10684
10685
10686
10687
10688
10689
10690
10691
10692
10693
10694
10695
10696
10697
10698
10699
10700
10701
10702
10703
10704
10705
10706
10707
10708
10709
10710
10711
10712
10713
10714
10715
10716
10717
10718
10719
10720
10721
10722
10723
10724
10725
10726
10727
10728
10729
10730
10731
10732
10733
10734
10735
10736
10737
10738
10739
10740
10741
10742
10743
10744
10745
10746
10747
10748
10749
10750
10751
10752
10753
10754
10755
10756
10757
10758
10759
10760
10761
10762
10763
10764
10765
10766
10767
10768
10769
10770
10771
10772
10773
10774
10775
10776
10777
10778
10779
10780
10781
10782
10783
10784
10785
10786
10787
10788
10789
10790
10791
10792
10793
10794
10795
10796
10797
10798
10799
10800
10801
10802
10803
10804
10805
10806
10807
10808
10809
10810
10811
10812
10813
10814
10815
10816
10817
10818
10819
10820
10821
10822
10823
10824
10825
10826
10827
10828
10829
10830
10831
10832
10833
10834
10835
10836
10837
10838
10839
10840
10841
10842
10843
10844
10845
10846
10847
10848
10849
10850
10851
10852
10853
10854
10855
10856
10857
10858
10859
10860
10861
10862
10863
10864
10865
10866
10867
10868
10869
10870
10871
10872
10873
10874
10875
10876
10877
10878
10879
10880
10881
10882
10883
10884
10885
10886
10887
10888
10889
10890
10891
10892
10893
10894
10895
10896
10897
10898
10899
10900
10901
10902
10903
10904
10905
10906
10907
10908
10909
10910
10911
10912
10913
10914
10915
10916
10917
10918
10919
10920
10921
10922
10923
10924
10925
10926
10927
10928
10929
10930
10931
10932
10933
10934
10935
10936
10937
10938
10939
10940
10941
10942
10943
10944
10945
10946
10947
10948
10949
10950
10951
10952
10953
10954
10955
10956
10957
10958
10959
10960
10961
10962
10963
10964
10965
10966
10967
10968
10969
10970
10971
10972
10973
10974
10975
10976
10977
10978
10979
10980
10981
10982
10983
10984
10985
10986
10987
10988
10989
10990
10991
10992
10993
10994
10995
10996
10997
10998
10999
11000
11001
11002
11003
11004
11005
11006
11007
11008
11009
11010
11011
11012
11013
11014
11015
11016
11017
11018
11019
11020
11021
11022
11023
11024
11025
11026
11027
11028
11029
11030
11031
11032
11033
11034
11035
11036
11037
11038
11039
11040
11041
11042
11043
11044
11045
11046
11047
11048
11049
11050
11051
11052
11053
11054
11055
11056
11057
11058
11059
11060
11061
11062
11063
11064
11065
11066
11067
11068
11069
11070
11071
11072
11073
11074
11075
11076
11077
11078
11079
11080
11081
11082
11083
11084
11085
11086
11087
11088
11089
11090
11091
11092
11093
11094
11095
11096
11097
11098
11099
11100
11101
11102
11103
11104
11105
11106
11107
11108
11109
11110
11111
11112
11113
11114
11115
11116
11117
11118
11119
11120
11121
11122
11123
11124
11125
11126
11127
11128
11129
11130
11131
11132
11133
11134
11135
11136
11137
11138
11139
11140
11141
11142
11143
11144
11145
11146
11147
11148
11149
11150
11151
11152
11153
11154
11155
11156
11157
11158
11159
11160
11161
11162
11163
11164
11165
11166
11167
11168
11169
11170
11171
11172
11173
11174
11175
11176
11177
11178
11179
11180
11181
11182
11183
11184
11185
11186
11187
11188
11189
11190
11191
11192
11193
11194
11195
11196
11197
11198
11199
11200
11201
11202
11203
11204
11205
11206
11207
11208
11209
11210
11211
11212
11213
11214
11215
11216
11217
11218
11219
11220
11221
11222
11223
11224
11225
11226
11227
11228
11229
11230
11231
11232
11233
11234
11235
11236
11237
11238
11239
11240
11241
11242
11243
11244
11245
11246
11247
11248
11249
11250
11251
11252
11253
11254
11255
11256
11257
11258
11259
11260
11261
11262
11263
11264
11265
11266
11267
11268
11269
11270
11271
11272
11273
11274
11275
11276
11277
11278
11279
11280
11281
11282
11283
11284
11285
11286
11287
11288
11289
11290
11291
11292
11293
11294
11295
11296
11297
11298
11299
11300
11301
11302
11303
11304
11305
11306
11307
11308
11309
11310
11311
11312
11313
11314
11315
11316
11317
11318
11319
11320
11321
11322
11323
11324
11325
11326
11327
11328
11329
11330
11331
11332
11333
11334
11335
11336
11337
11338
11339
11340
11341
11342
11343
11344
11345
11346
11347
11348
11349
11350
11351
11352
11353
11354
11355
11356
11357
11358
11359
11360
11361
11362
11363
11364
11365
11366
11367
11368
11369
11370
11371
11372
11373
11374
11375
11376
11377
11378
11379
11380
11381
11382
11383
11384
11385
11386
11387
11388
11389
11390
11391
11392
11393
11394
11395
11396
11397
11398
11399
11400
11401
11402
11403
11404
11405
11406
11407
11408
11409
11410
11411
11412
11413
11414
11415
11416
11417
11418
11419
11420
11421
11422
11423
11424
11425
11426
11427
11428
11429
11430
11431
11432
11433
11434
11435
11436
11437
11438
11439
11440
11441
11442
11443
11444
11445
11446
11447
11448
11449
11450
11451
11452
11453
11454
11455
11456
11457
11458
11459
11460
11461
11462
11463
11464
11465
11466
11467
11468
11469
11470
11471
11472
11473
11474
11475
11476
11477
11478
11479
11480
11481
11482
11483
11484
11485
11486
11487
11488
11489
11490
11491
11492
11493
11494
11495
11496
11497
11498
11499
11500
11501
11502
11503
11504
11505
11506
11507
11508
11509
11510
11511
11512
11513
11514
11515
11516
11517
11518
11519
11520
11521
11522
11523
11524
11525
11526
11527
11528
11529
11530
11531
11532
11533
11534
11535
11536
11537
11538
11539
11540
11541
11542
11543
11544
11545
11546
11547
11548
11549
11550
11551
11552
11553
11554
11555
11556
11557
11558
11559
11560
11561
11562
11563
11564
11565
11566
11567
11568
11569
11570
11571
11572
11573
11574
11575
11576
11577
11578
11579
11580
11581
11582
11583
11584
11585
11586
11587
11588
11589
11590
11591
11592
11593
11594
11595
11596
11597
11598
11599
11600
11601
11602
11603
11604
11605
11606
11607
11608
11609
11610
11611
11612
11613
11614
11615
11616
11617
11618
11619
11620
11621
11622
11623
11624
11625
11626
11627
11628
11629
11630
11631
11632
11633
11634
11635
11636
11637
11638
11639
11640
11641
11642
11643
11644
11645
11646
11647
11648
11649
11650
11651
11652
11653
11654
11655
11656
11657
11658
11659
11660
11661
11662
11663
11664
11665
11666
11667
11668
11669
11670
11671
11672
11673
11674
11675
11676
11677
11678
11679
11680
11681
11682
11683
11684
11685
11686
11687
11688
11689
11690
11691
11692
11693
11694
11695
11696
11697
11698
11699
11700
11701
11702
11703
11704
11705
11706
11707
11708
11709
11710
11711
11712
11713
11714
11715
11716
11717
11718
11719
11720
11721
11722
11723
11724
11725
11726
11727
11728
11729
11730
11731
11732
11733
11734
11735
11736
11737
11738
11739
11740
11741
11742
11743
11744
11745
11746
11747
11748
11749
11750
11751
11752
11753
11754
11755
11756
11757
11758
11759
11760
11761
11762
11763
11764
11765
11766
11767
11768
11769
11770
11771
11772
11773
11774
11775
11776
11777
11778
11779
11780
11781
11782
11783
11784
11785
11786
11787
11788
11789
11790
11791
11792
11793
11794
11795
11796
11797
11798
11799
11800
11801
11802
11803
11804
11805
11806
11807
11808
11809
11810
11811
11812
11813
11814
11815
11816
11817
11818
11819
11820
11821
11822
11823
11824
11825
11826
11827
11828
11829
11830
11831
11832
11833
11834
11835
11836
11837
11838
11839
11840
11841
11842
11843
11844
11845
11846
11847
11848
11849
11850
11851
11852
11853
11854
11855
11856
11857
11858
11859
11860
11861
11862
11863
11864
11865
11866
11867
11868
11869
11870
11871
11872
11873
11874
11875
11876
11877
11878
11879
11880
11881
11882
11883
11884
11885
11886
11887
11888
11889
11890
11891
11892
11893
11894
11895
11896
11897
11898
11899
11900
11901
11902
11903
11904
11905
11906
11907
11908
11909
11910
11911
11912
11913
11914
11915
11916
11917
11918
11919
11920
11921
11922
11923
11924
11925
11926
11927
11928
11929
11930
11931
11932
11933
11934
11935
11936
11937
11938
11939
11940
11941
11942
11943
11944
11945
11946
11947
11948
11949
11950
11951
11952
11953
11954
11955
11956
11957
11958
11959
11960
11961
11962
11963
11964
11965
11966
11967
11968
11969
11970
11971
11972
11973
11974
11975
11976
11977
11978
11979
11980
11981
11982
11983
11984
11985
11986
11987
11988
11989
11990
11991
11992
11993
11994
11995
11996
11997
11998
11999
12000
12001
12002
12003
12004
12005
12006
12007
12008
12009
12010
12011
12012
12013
12014
12015
12016
12017
12018
12019
12020
12021
12022
12023
12024
12025
12026
12027
12028
12029
12030
12031
12032
12033
12034
12035
12036
12037
12038
12039
12040
12041
12042
12043
12044
12045
12046
12047
12048
12049
12050
12051
12052
12053
12054
12055
12056
12057
12058
12059
12060
12061
12062
12063
12064
12065
12066
12067
12068
12069
12070
12071
12072
12073
12074
12075
12076
12077
12078
12079
12080
12081
12082
12083
12084
12085
12086
12087
12088
12089
12090
12091
12092
12093
12094
12095
12096
12097
12098
12099
12100
12101
12102
12103
12104
12105
12106
12107
12108
12109
12110
12111
12112
12113
12114
12115
12116
12117
12118
12119
12120
12121
12122
12123
12124
12125
12126
12127
12128
12129
12130
12131
12132
12133
12134
12135
12136
12137
12138
12139
12140
12141
12142
12143
12144
12145
12146
12147
12148
12149
12150
12151
12152
12153
12154
12155
12156
12157
12158
12159
12160
12161
12162
12163
12164
12165
12166
12167
12168
12169
12170
12171
12172
12173
12174
12175
12176
12177
12178
12179
12180
12181
12182
12183
12184
12185
12186
12187
12188
12189
12190
12191
12192
12193
12194
12195
12196
12197
12198
12199
12200
12201
12202
12203
12204
12205
12206
12207
12208
12209
12210
12211
12212
12213
12214
12215
12216
12217
12218
12219
12220
12221
12222
12223
12224
12225
12226
12227
12228
12229
12230
12231
12232
12233
12234
12235
12236
12237
12238
12239
12240
12241
12242
12243
12244
12245
12246
12247
12248
12249
12250
12251
12252
12253
12254
12255
12256
12257
12258
12259
12260
12261
12262
12263
12264
12265
12266
12267
12268
12269
12270
12271
12272
12273
12274
12275
12276
12277
12278
12279
12280
12281
12282
12283
12284
12285
12286
12287
12288
12289
12290
12291
12292
12293
12294
12295
12296
12297
12298
12299
12300
12301
12302
12303
12304
12305
12306
12307
12308
12309
12310
12311
12312
12313
12314
12315
12316
12317
12318
12319
12320
12321
12322
12323
12324
12325
12326
12327
12328
12329
12330
12331
12332
12333
12334
12335
12336
12337
12338
12339
12340
12341
12342
12343
12344
12345
12346
12347
12348
12349
12350
12351
12352
12353
12354
12355
12356
12357
12358
12359
12360
12361
12362
12363
12364
12365
12366
12367
12368
12369
12370
12371
12372
12373
12374
12375
12376
12377
12378
12379
12380
12381
12382
12383
12384
12385
12386
12387
12388
12389
12390
12391
12392
12393
12394
12395
12396
12397
12398
12399
12400
12401
12402
12403
12404
12405
12406
12407
12408
12409
12410
12411
12412
12413
12414
12415
12416
12417
12418
12419
12420
12421
12422
12423
12424
12425
12426
12427
12428
12429
12430
12431
12432
12433
12434
12435
12436
12437
12438
12439
12440
12441
12442
12443
12444
12445
12446
12447
12448
12449
12450
12451
12452
12453
12454
12455
12456
12457
12458
12459
12460
12461
12462
12463
12464
12465
12466
12467
12468
12469
12470
12471
12472
12473
12474
12475
12476
12477
12478
12479
12480
12481
12482
12483
12484
12485
12486
12487
12488
12489
12490
12491
12492
12493
12494
12495
12496
12497
12498
12499
12500
12501
12502
12503
12504
12505
12506
12507
12508
12509
12510
12511
12512
12513
12514
12515
12516
12517
12518
12519
12520
12521
12522
12523
12524
12525
12526
12527
12528
12529
12530
12531
12532
12533
12534
12535
12536
12537
12538
12539
12540
12541
12542
12543
12544
12545
12546
12547
12548
12549
12550
12551
12552
12553
12554
12555
12556
12557
12558
12559
12560
12561
12562
12563
12564
12565
12566
12567
12568
12569
12570
12571
12572
12573
12574
12575
12576
12577
12578
12579
12580
12581
12582
12583
12584
12585
12586
12587
12588
12589
12590
12591
12592
12593
12594
12595
12596
12597
12598
12599
12600
12601
12602
12603
12604
12605
12606
12607
12608
12609
12610
12611
12612
12613
12614
12615
12616
12617
12618
12619
12620
12621
12622
12623
12624
12625
12626
12627
12628
12629
12630
12631
12632
12633
12634
12635
12636
12637
12638
12639
12640
12641
12642
12643
12644
12645
12646
12647
12648
12649
12650
12651
12652
12653
12654
12655
12656
12657
12658
12659
12660
12661
12662
12663
12664
12665
12666
12667
12668
12669
12670
12671
12672
12673
12674
12675
12676
12677
12678
12679
12680
12681
12682
12683
12684
12685
12686
12687
12688
12689
12690
12691
12692
12693
12694
12695
12696
12697
12698
12699
12700
12701
12702
12703
12704
12705
12706
12707
12708
12709
12710
12711
12712
12713
12714
12715
12716
12717
12718
12719
12720
12721
12722
12723
12724
12725
12726
12727
12728
12729
12730
12731
12732
12733
12734
12735
12736
12737
12738
12739
12740
12741
12742
12743
12744
12745
12746
12747
12748
12749
12750
12751
12752
12753
12754
12755
12756
12757
12758
12759
12760
12761
12762
12763
12764
12765
12766
12767
12768
12769
12770
12771
12772
12773
12774
12775
12776
12777
12778
12779
12780
12781
12782
12783
12784
12785
12786
12787
12788
12789
12790
12791
12792
12793
12794
12795
12796
12797
12798
12799
12800
12801
12802
12803
12804
12805
12806
12807
12808
12809
12810
12811
12812
12813
12814
12815
12816
12817
12818
12819
12820
12821
12822
12823
12824
12825
12826
12827
12828
12829
12830
12831
12832
12833
12834
12835
12836
12837
12838
12839
12840
12841
12842
12843
12844
12845
12846
12847
12848
12849
12850
12851
12852
12853
12854
12855
12856
12857
12858
12859
12860
12861
12862
12863
12864
12865
12866
12867
12868
12869
12870
12871
12872
12873
12874
12875
12876
12877
12878
12879
12880
12881
12882
12883
12884
12885
12886
12887
12888
12889
12890
12891
12892
12893
12894
12895
12896
12897
12898
12899
12900
12901
12902
12903
12904
12905
12906
12907
12908
12909
12910
12911
12912
12913
12914
12915
12916
12917
12918
12919
12920
12921
12922
12923
12924
12925
12926
12927
12928
12929
12930
12931
12932
12933
12934
12935
12936
12937
12938
12939
12940
12941
12942
12943
12944
12945
12946
12947
12948
12949
12950
12951
12952
12953
12954
12955
12956
12957
12958
12959
12960
12961
12962
12963
12964
12965
12966
12967
12968
12969
12970
12971
12972
12973
12974
12975
12976
12977
12978
12979
12980
12981
12982
12983
12984
12985
12986
12987
12988
12989
12990
12991
12992
12993
12994
12995
12996
12997
12998
12999
13000
13001
13002
13003
13004
13005
13006
13007
13008
13009
13010
13011
13012
13013
13014
13015
13016
13017
13018
13019
13020
13021
13022
13023
13024
13025
13026
13027
13028
13029
13030
13031
13032
13033
13034
13035
13036
13037
13038
13039
13040
13041
13042
13043
13044
13045
13046
13047
13048
13049
13050
13051
13052
13053
13054
13055
13056
13057
13058
13059
13060
13061
13062
13063
13064
13065
13066
13067
13068
13069
13070
13071
13072
13073
13074
13075
13076
13077
13078
13079
13080
13081
13082
13083
13084
13085
13086
13087
13088
13089
13090
13091
13092
13093
13094
13095
13096
13097
13098
13099
13100
13101
13102
13103
13104
13105
13106
13107
13108
13109
13110
13111
13112
13113
13114
13115
13116
13117
13118
13119
13120
13121
13122
13123
13124
13125
13126
13127
13128
13129
13130
13131
13132
13133
13134
13135
13136
13137
13138
13139
13140
13141
13142
13143
13144
13145
13146
13147
13148
13149
13150
13151
13152
13153
13154
13155
13156
13157
13158
13159
13160
13161
13162
13163
13164
13165
13166
13167
13168
13169
13170
13171
13172
13173
13174
13175
13176
13177
13178
13179
13180
13181
13182
13183
13184
13185
13186
13187
13188
13189
13190
13191
13192
13193
13194
13195
13196
13197
13198
13199
13200
13201
13202
13203
13204
13205
13206
13207
13208
13209
13210
13211
13212
13213
13214
13215
13216
13217
13218
13219
13220
13221
13222
13223
13224
13225
13226
13227
13228
13229
13230
13231
13232
13233
13234
13235
13236
13237
13238
13239
13240
13241
13242
13243
13244
13245
13246
13247
13248
13249
13250
13251
13252
13253
13254
13255
13256
13257
13258
13259
13260
13261
13262
13263
13264
13265
13266
13267
13268
13269
13270
13271
13272
13273
13274
13275
13276
13277
13278
13279
13280
13281
13282
13283
13284
13285
13286
13287
13288
13289
13290
13291
13292
13293
13294
13295
13296
13297
13298
13299
13300
13301
13302
13303
13304
13305
13306
13307
13308
13309
13310
13311
13312
13313
13314
13315
13316
13317
13318
13319
13320
13321
13322
13323
13324
13325
13326
13327
13328
13329
13330
13331
13332
13333
13334
13335
13336
13337
13338
13339
13340
13341
13342
13343
13344
13345
13346
13347
13348
13349
13350
13351
13352
13353
13354
13355
13356
13357
13358
13359
13360
13361
13362
13363
13364
13365
13366
13367
13368
13369
13370
13371
13372
13373
13374
13375
13376
13377
13378
13379
13380
13381
13382
13383
13384
13385
13386
13387
13388
13389
13390
13391
13392
13393
13394
13395
13396
13397
13398
13399
13400
13401
13402
13403
13404
13405
13406
13407
13408
13409
13410
13411
13412
13413
13414
13415
13416
13417
13418
13419
13420
13421
13422
13423
13424
13425
13426
13427
13428
13429
13430
13431
13432
13433
13434
13435
13436
13437
13438
13439
13440
13441
13442
13443
13444
13445
13446
13447
13448
13449
13450
13451
13452
13453
13454
13455
13456
13457
13458
13459
13460
13461
13462
13463
13464
13465
13466
13467
13468
13469
13470
13471
13472
13473
13474
13475
13476
13477
13478
13479
13480
13481
13482
13483
13484
13485
13486
13487
13488
13489
13490
13491
13492
13493
13494
13495
13496
13497
13498
13499
13500
13501
13502
13503
13504
13505
13506
13507
13508
13509
13510
13511
13512
13513
13514
13515
13516
13517
13518
13519
13520
13521
13522
13523
13524
13525
13526
13527
13528
13529
13530
13531
13532
13533
13534
13535
13536
13537
13538
13539
13540
13541
13542
13543
13544
13545
13546
13547
13548
13549
13550
13551
13552
13553
13554
13555
13556
13557
13558
13559
13560
13561
13562
13563
13564
13565
13566
13567
13568
13569
13570
13571
13572
13573
13574
13575
13576
13577
13578
13579
13580
13581
13582
13583
13584
13585
13586
13587
13588
13589
13590
13591
13592
13593
13594
13595
13596
13597
13598
13599
13600
13601
13602
13603
13604
13605
13606
13607
13608
13609
13610
13611
13612
13613
13614
13615
13616
13617
13618
13619
13620
13621
13622
13623
13624
13625
13626
13627
13628
13629
13630
13631
13632
13633
13634
13635
13636
13637
13638
13639
13640
13641
13642
13643
13644
13645
13646
13647
13648
13649
13650
13651
13652
13653
13654
13655
13656
13657
13658
13659
13660
13661
13662
13663
13664
13665
13666
13667
13668
13669
13670
13671
13672
13673
13674
13675
13676
13677
13678
13679
13680
13681
13682
13683
13684
13685
13686
13687
13688
13689
13690
13691
13692
13693
13694
13695
13696
13697
13698
13699
13700
13701
13702
13703
13704
13705
13706
13707
13708
13709
13710
13711
13712
13713
13714
13715
13716
13717
13718
13719
13720
13721
13722
13723
13724
13725
13726
13727
13728
13729
13730
13731
13732
13733
13734
13735
13736
13737
13738
13739
13740
13741
13742
13743
13744
13745
13746
13747
13748
13749
13750
13751
13752
13753
13754
13755
13756
13757
13758
13759
13760
13761
13762
13763
13764
13765
13766
13767
13768
13769
13770
13771
13772
13773
13774
13775
13776
13777
13778
13779
13780
13781
13782
13783
13784
13785
13786
13787
13788
13789
13790
13791
13792
13793
13794
13795
13796
13797
13798
13799
13800
13801
13802
13803
13804
13805
13806
13807
13808
13809
13810
13811
13812
13813
13814
13815
13816
13817
13818
13819
13820
13821
13822
13823
13824
13825
13826
13827
13828
13829
13830
13831
13832
13833
13834
13835
13836
13837
13838
13839
13840
13841
13842
13843
13844
13845
13846
13847
13848
13849
13850
13851
13852
13853
13854
13855
13856
13857
13858
13859
13860
13861
13862
13863
13864
13865
13866
13867
13868
13869
13870
13871
13872
13873
13874
13875
13876
13877
13878
13879
13880
13881
13882
13883
13884
13885
13886
13887
13888
13889
13890
13891
13892
13893
13894
13895
13896
13897
13898
13899
13900
13901
13902
13903
13904
13905
13906
13907
13908
13909
13910
13911
13912
13913
13914
13915
13916
13917
13918
13919
13920
13921
13922
13923
13924
13925
13926
13927
13928
13929
13930
13931
13932
13933
13934
13935
13936
13937
13938
13939
13940
13941
13942
13943
13944
13945
13946
13947
13948
13949
13950
13951
13952
13953
13954
13955
13956
13957
13958
13959
13960
13961
13962
13963
13964
13965
13966
13967
13968
13969
13970
13971
13972
13973
13974
13975
13976
13977
13978
13979
13980
13981
13982
13983
13984
13985
13986
13987
13988
13989
13990
13991
13992
13993
13994
13995
13996
13997
13998
13999
14000
14001
14002
14003
14004
14005
14006
14007
14008
14009
14010
14011
14012
14013
14014
14015
14016
14017
14018
14019
14020
14021
14022
14023
14024
14025
14026
14027
14028
14029
14030
14031
14032
14033
14034
14035
14036
14037
14038
14039
14040
14041
14042
14043
14044
14045
14046
14047
14048
14049
14050
14051
14052
14053
14054
14055
14056
14057
14058
14059
14060
14061
14062
14063
14064
14065
14066
14067
14068
14069
14070
14071
14072
14073
14074
14075
14076
14077
14078
14079
14080
14081
14082
14083
14084
14085
14086
14087
14088
14089
14090
14091
14092
14093
14094
14095
14096
14097
14098
14099
14100
14101
14102
14103
14104
14105
14106
14107
14108
14109
14110
14111
14112
14113
14114
14115
14116
14117
14118
14119
14120
14121
14122
14123
14124
14125
14126
14127
14128
14129
14130
14131
14132
14133
14134
14135
14136
14137
14138
14139
14140
14141
14142
14143
14144
14145
14146
14147
14148
14149
14150
14151
14152
14153
14154
14155
14156
14157
14158
14159
14160
14161
14162
14163
14164
14165
14166
14167
14168
14169
14170
14171
14172
14173
14174
14175
14176
14177
14178
14179
14180
14181
14182
14183
14184
14185
14186
14187
14188
14189
14190
14191
14192
14193
14194
14195
14196
14197
14198
14199
14200
14201
14202
14203
14204
14205
14206
14207
14208
14209
14210
14211
14212
14213
14214
14215
14216
14217
14218
14219
14220
14221
14222
14223
14224
14225
14226
14227
14228
14229
14230
14231
14232
14233
14234
14235
14236
14237
14238
14239
14240
14241
14242
14243
14244
14245
14246
14247
14248
14249
14250
14251
14252
14253
14254
14255
14256
14257
14258
14259
14260
14261
14262
14263
14264
14265
14266
14267
14268
14269
14270
14271
14272
14273
14274
14275
14276
14277
14278
14279
14280
14281
14282
14283
14284
14285
14286
14287
14288
14289
14290
14291
14292
14293
14294
14295
14296
14297
14298
14299
14300
14301
14302
14303
14304
14305
14306
14307
14308
14309
14310
14311
14312
14313
14314
14315
14316
14317
14318
14319
14320
14321
14322
14323
14324
14325
14326
14327
14328
14329
14330
14331
14332
14333
14334
14335
14336
14337
14338
14339
14340
14341
14342
14343
14344
14345
14346
14347
14348
14349
14350
14351
14352
14353
14354
14355
14356
14357
14358
14359
14360
14361
14362
14363
14364
14365
14366
14367
14368
14369
14370
14371
14372
14373
14374
14375
14376
14377
14378
14379
14380
14381
14382
14383
14384
14385
14386
14387
14388
14389
14390
14391
14392
14393
14394
14395
14396
14397
14398
14399
14400
14401
14402
14403
14404
14405
14406
14407
14408
14409
14410
14411
14412
14413
14414
14415
14416
14417
14418
14419
14420
14421
14422
14423
14424
14425
14426
14427
14428
14429
14430
14431
14432
14433
14434
14435
14436
14437
14438
14439
14440
14441
14442
14443
14444
14445
14446
14447
14448
14449
14450
14451
14452
14453
14454
14455
14456
14457
14458
14459
14460
14461
14462
14463
14464
14465
14466
14467
14468
14469
14470
14471
14472
14473
14474
14475
14476
14477
14478
14479
14480
14481
14482
14483
14484
14485
14486
14487
14488
14489
14490
14491
14492
14493
14494
14495
14496
14497
14498
14499
14500
14501
14502
14503
14504
14505
14506
14507
14508
14509
14510
14511
14512
14513
14514
14515
14516
14517
14518
14519
14520
14521
14522
14523
14524
14525
14526
14527
14528
14529
14530
14531
14532
14533
14534
14535
14536
14537
14538
14539
14540
14541
14542
14543
14544
14545
14546
14547
14548
14549
14550
14551
14552
14553
14554
14555
14556
14557
14558
14559
14560
14561
14562
14563
14564
14565
14566
14567
14568
14569
14570
14571
14572
14573
14574
14575
14576
14577
14578
14579
14580
14581
14582
14583
14584
14585
14586
14587
14588
14589
14590
14591
14592
14593
14594
14595
14596
14597
14598
14599
14600
14601
14602
14603
14604
14605
14606
14607
14608
14609
14610
14611
14612
14613
14614
14615
14616
14617
14618
14619
14620
14621
14622
14623
14624
14625
14626
14627
14628
14629
14630
14631
14632
14633
14634
14635
14636
14637
14638
14639
14640
14641
14642
14643
14644
14645
14646
14647
14648
14649
14650
14651
14652
14653
14654
14655
14656
14657
14658
14659
14660
14661
14662
14663
14664
14665
14666
14667
14668
14669
14670
14671
14672
14673
14674
14675
14676
14677
14678
14679
14680
14681
14682
14683
14684
14685
14686
14687
14688
14689
14690
14691
14692
14693
14694
14695
14696
14697
14698
14699
14700
14701
14702
14703
14704
14705
14706
14707
14708
14709
14710
14711
14712
14713
14714
14715
14716
14717
14718
14719
14720
14721
14722
14723
14724
14725
14726
14727
14728
14729
14730
14731
14732
14733
14734
14735
14736
14737
14738
14739
14740
14741
14742
14743
14744
14745
14746
14747
14748
14749
14750
14751
14752
14753
14754
14755
14756
14757
14758
14759
14760
14761
14762
14763
14764
14765
14766
14767
14768
14769
14770
14771
14772
14773
14774
14775
14776
14777
14778
14779
14780
14781
14782
14783
14784
14785
14786
14787
14788
14789
14790
14791
14792
14793
14794
14795
14796
14797
14798
14799
14800
14801
14802
14803
14804
14805
14806
14807
14808
14809
14810
14811
14812
14813
14814
14815
14816
14817
14818
14819
14820
14821
14822
14823
14824
14825
14826
14827
14828
14829
14830
14831
14832
14833
14834
14835
14836
14837
14838
14839
14840
14841
14842
14843
14844
14845
14846
14847
14848
14849
14850
14851
14852
14853
14854
14855
14856
14857
14858
14859
14860
14861
14862
14863
14864
14865
14866
14867
14868
14869
14870
14871
14872
14873
14874
14875
14876
14877
14878
14879
14880
14881
14882
14883
14884
14885
14886
14887
14888
14889
14890
14891
14892
14893
14894
14895
14896
14897
14898
14899
14900
14901
14902
14903
14904
14905
14906
14907
14908
14909
14910
14911
14912
14913
14914
14915
14916
14917
14918
14919
14920
14921
14922
14923
14924
14925
14926
14927
14928
14929
14930
14931
14932
14933
14934
14935
14936
14937
14938
14939
14940
14941
14942
14943
14944
14945
14946
14947
14948
14949
14950
14951
14952
14953
14954
14955
14956
14957
14958
14959
14960
14961
14962
14963
14964
14965
14966
14967
14968
14969
14970
14971
14972
14973
14974
14975
14976
14977
14978
14979
14980
14981
14982
14983
14984
14985
14986
14987
14988
14989
14990
14991
14992
14993
14994
14995
14996
14997
14998
14999
15000
15001
15002
15003
15004
15005
15006
15007
15008
15009
15010
15011
15012
15013
15014
15015
15016
15017
15018
15019
15020
15021
15022
15023
15024
15025
15026
15027
15028
15029
15030
15031
15032
15033
15034
15035
15036
15037
15038
15039
15040
15041
15042
15043
15044
15045
15046
15047
15048
15049
15050
15051
15052
15053
15054
15055
15056
15057
15058
15059
15060
15061
15062
15063
15064
15065
15066
15067
15068
15069
15070
15071
15072
15073
15074
15075
15076
15077
15078
15079
15080
15081
15082
15083
15084
15085
15086
15087
15088
15089
15090
15091
15092
15093
15094
15095
15096
15097
15098
15099
15100
15101
15102
15103
15104
15105
15106
15107
15108
15109
15110
15111
15112
15113
15114
15115
15116
15117
15118
15119
15120
15121
15122
15123
15124

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" "http://www.w3.org/TR/REC-html40/loose.dtd">
<html><head><title>C++ Standard Library Defect Report List</title>

<style>ins {background-color:#FFFFA0}
del {background-color:#FFFFA0}</style></head>

<body bgcolor="#ffffff" text="#000000">
<table>
<tbody><tr>
<td align="left">Doc. no.</td>
<td align="left">N2131=06-0201</td>
</tr>
<tr>
<td align="left">Date:</td>
<td align="left">2006-11-03</td>
</tr>
<tr>
<td align="left">Project:</td>
<td align="left">Programming Language C++</td>
</tr>
<tr>
<td align="left">Reply to:</td>
<td align="left">Howard Hinnant &lt;howard.hinnant@gmail.com&gt;</td>
</tr>
</tbody></table>
<h1>C++ Standard Library Defect Report List (Revision R45)</h1>
  <p>Reference ISO/IEC IS 14882:1998(E)</p>
  <p>Also see:</p>
    <ul>
      <li>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-toc.html">Table of Contents</a> for all library issues.</li>
      <li>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-index.html">Index by Section</a> for all library issues.</li>
      <li>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-status.html">Index by Status</a> for all library issues.</li>
      <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html">Library Active Issues List</a></li>
      <li><a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html">Library Closed Issues List</a></li>
    </ul>
  <p>This document contains only library issues which have been closed
  by the Library Working Group (LWG) after being found to be defects
  in the standard.  That is, issues which have a status of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>, or <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#RR">RR</a>. See the
  <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html">Library Closed Issues List</a> for issues closed as non-defects.  See the
  <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html">Library Active Issues List</a> for active issues and more information.  The
  introductory material in that document also applies to this
  document.</p>
<h2>Revision History</h2>
<ul>
<li>R45: 
2006-11-03 post-Portland mailing.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#520">520</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#521">521</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530">530</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#537">537</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#538">538</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#540">540</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#541">541</a> to WP.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#516">516</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#554">554</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#555">555</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#558">558</a> to NAD.
Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#569">569</a> to Dup.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#518">518</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#523">523</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#524">524</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#542">542</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#556">556</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#557">557</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#559">559</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#597">597</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#606">606</a> to Open.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#543">543</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#545">545</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#598">598</a> - <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#603">603</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#605">605</a> to Ready.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#551">551</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#604">604</a> to Review.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#593">593</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#609">609</a>.
</li>
<li>R44: 
2006-09-08 pre-Portland mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#583">583</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#592">592</a>.
</li>
<li>R43: 
2006-06-23 mid-term mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#575">575</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#582">582</a>.
Reopened <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#255">255</a>.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#520">520</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#541">541</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#544">544</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#569">569</a> to Tentatively Ready.
</li>
<li>R42: 
2006-04-21 post-Berlin mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#567">567</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#572">572</a>.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#499">499</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#501">501</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#506">506</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#509">509</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#511">511</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#513">513</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#514">514</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#517">517</a> to NAD.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#502">502</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#503">503</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#515">515</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#516">516</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#522">522</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#525">525</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#529">529</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#532">532</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#536">536</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#539">539</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#548">548</a> to Open.
Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#521">521</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#530">530</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#531">531</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#537">537</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#538">538</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#540">540</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#549">549</a> to Ready.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#247">247</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#294">294</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#369">369</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#371">371</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#376">376</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#384">384</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#475">475</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#495">495</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#497">497</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#505">505</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#507">507</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#508">508</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#519">519</a> to WP.
Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#534">534</a> to Review.
</li>
<li>R41: 
2006-02-24 pre-Berlin mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#536">536</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#566">566</a>.
Moved <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#342">342</a> from Ready to Open.
Reopened <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#309">309</a>.
</li>
<li>R40: 
2005-12-16 mid-term mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#529">529</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#535">535</a>.
</li>
<li>R39: 
2005-10-14 post-Mont Tremblant mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#526">526</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#528">528</a>.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#280">280</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#461">461</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#464">464</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#465">465</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#467">467</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#468">468</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#474">474</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#496">496</a> from Ready to WP as per the vote from Mont Tremblant.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#247">247</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#294">294</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#342">342</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#369">369</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#371">371</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#376">376</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#384">384</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#475">475</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#495">495</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#497">497</a> from Review to Ready.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#498">498</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#506">506</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#509">509</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#510">510</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#511">511</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#512">512</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#513">513</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#514">514</a> from New to Open.
Moved issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#505">505</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#507">507</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#508">508</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#519">519</a> from New to Ready.
Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#500">500</a> from New to NAD.
Moved issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#518">518</a> from New to Review.
</li>
<li>R38: 
2005-07-03 pre-Mont Tremblant mailing.
Merged open TR1 issues in <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#504">504</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#522">522</a>.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#523">523</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#523">523</a>
</li>
<li>R37: 
2005-06 mid-term mailing.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#498">498</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#503">503</a>.
</li>
<li>R36: 
2005-04 post-Lillehammer mailing. All issues in "ready" status except
for <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#454">454</a> were moved to "DR" status, and all issues
previously in "DR" status were moved to "WP".
</li>
<li>R35: 
2005-03 pre-Lillehammer mailing.
</li>
<li>R34: 
2005-01 mid-term mailing.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#488">488</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#494">494</a>.
</li>
<li>R33: 
2004-11 post-Redmond mailing. Reflects actions taken in Redmond.
</li>
<li>R32: 
2004-09 pre-Redmond mailing: reflects new proposed resolutions and
new issues received after the 2004-07 mailing.  Added
new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#479">479</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#481">481</a>.
</li>
<li>R31: 
2004-07 mid-term mailing: reflects new proposed resolutions and
new issues received after the post-Sydney mailing.  Added
new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#463">463</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#478">478</a>.
</li>
<li>R30: 
Post-Sydney mailing: reflects decisions made at the Sydney meeting.
Voted all "Ready" issues from R29 into the working paper.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#460">460</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#462">462</a>.
</li>
<li>R29: 
Pre-Sydney mailing.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#441">441</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#457">457</a>.
</li>
<li>R28: 
Post-Kona mailing: reflects decisions made at the Kona meeting.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#432">432</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#440">440</a>.
</li>
<li>R27: 
Pre-Kona mailing.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#404">404</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#431">431</a>.
</li>
<li>R26: 
Post-Oxford mailing: reflects decisions made at the Oxford meeting.
All issues in Ready status were voted into DR status.  All issues in
DR status were voted into WP status.
</li>
<li>R25: 
Pre-Oxford mailing.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#390">390</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#402">402</a>.
</li>
<li>R24: 
Post-Santa Cruz mailing: reflects decisions made at the Santa Cruz
meeting.  All Ready issues from R23 with the exception of <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253">253</a>, which has been given a new proposed resolution, were
moved to DR status.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#383">383</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#389">389</a>.  (Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#387">387</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#389">389</a> were discussed
at the meeting.)  Made progress on issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a>: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a> have been moved to Ready status, and the only remaining
concerns with <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a> involve wording.
</li>
<li>R23: 
Pre-Santa Cruz mailing.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#367">367</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#382">382</a>.
Moved issues in the TC to TC status.
</li>
<li>R22: 
Post-Curaçao mailing.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#362">362</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#366">366</a>.
</li>
<li>R21: 
Pre-Curaçao mailing.  Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#351">351</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#361">361</a>.
</li>
<li>R20: 
Post-Redmond mailing; reflects actions taken in Redmond.  Added
new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#336">336</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a>, of which issues 
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#347">347</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#350">350</a> were added since Redmond, hence
not discussed at the meeting.  

All Ready issues were moved to DR status, with the exception of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#284">284</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#241">241</a>, and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a>.

Noteworthy issues discussed at Redmond include 
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#120">120</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#202">202</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#233">233</a>, 
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#270">270</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253">253</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#254">254</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>.
</li>
<li>R19: 
Pre-Redmond mailing.  Added new issues 
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#335">335</a>.
</li>
<li>R18: 
Post-Copenhagen mailing; reflects actions taken in Copenhagen.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#312">312</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#317">317</a>, and discussed
new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#271">271</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#314">314</a>.

Changed status of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#118">118</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#136">136</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#153">153</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#165">165</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#171">171</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#183">183</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#184">184</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#185">185</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#186">186</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#214">214</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#221">221</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#234">234</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#237">237</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#243">243</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#248">248</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#251">251</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#252">252</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#256">256</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#260">260</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#261">261</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#262">262</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#263">263</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#265">265</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#268">268</a>
to DR.

Changed status of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#49">49</a>  <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#117">117</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#182">182</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#230">230</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#232">232</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#238">238</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#241">241</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#242">242</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#250">250</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#259">259</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#266">266</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#271">271</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#272">272</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#273">273</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#275">275</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#281">281</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#284">284</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#285">285</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#286">286</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#288">288</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#292">292</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#295">295</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#297">297</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#298">298</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#301">301</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#303">303</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#306">306</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#307">307</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#308">308</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#312">312</a>
to Ready.

Closed issues 
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#277">277</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#279">279</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#287">287</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#289">289</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#293">293</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#302">302</a> <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#313">313</a>
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#314">314</a>
as NAD.

</li>
<li>R17: 
Pre-Copenhagen mailing.  Converted issues list to XML.  Added proposed
resolutions for issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#49">49</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#76">76</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#91">91</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#235">235</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#250">250</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#267">267</a>.
Added new issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#278">278</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#311">311</a>.
</li>
<li>R16:  
post-Toronto mailing; reflects actions taken in Toronto. Added new
issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#265">265</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#277">277</a>.  Changed status of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#3">3</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#8">8</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#9">9</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#19">19</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#26">26</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#31">31</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#61">61</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#63">63</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#86">86</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#108">108</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#115">115</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#122">122</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#127">127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#129">129</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#134">134</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#137">137</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#142">142</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#144">144</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#146">146</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#147">147</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#159">159</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#164">164</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#170">170</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#181">181</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#199">199</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#208">208</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#209">209</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#210">210</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#211">211</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#212">212</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#217">217</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#220">220</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#222">222</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#223">223</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#224">224</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#227">227</a> to "DR".  Reopened issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#23">23</a>. Reopened
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#187">187</a>. Changed issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#2">2</a> and
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> to NAD. Fixed a typo in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#17">17</a>. Fixed
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#70">70</a>: signature should be changed both places it
appears. Fixed issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#160">160</a>: previous version didn't fix
the bug in enough places.
</li>
<li>R15: 
pre-Toronto mailing. Added issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#233">233</a>-<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#264">264</a>. Some small HTML formatting
changes so that we pass Weblint tests.
</li>
<li>R14: 
post-Tokyo II mailing; reflects committee actions taken in
Tokyo. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#232">232</a>. (00-0019R1/N1242)
</li>
<li>R13: 
pre-Tokyo II updated: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#212">212</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#227">227</a>.
</li>
<li>R12: 
pre-Tokyo II mailing: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#199">199</a> to
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#211">211</a>. Added "and paragraph 5" to the proposed resolution
of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#29">29</a>.  Add further rationale to issue
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#178">178</a>.
</li>
<li>R11: 
post-Kona mailing: Updated to reflect LWG and full committee actions
in Kona (99-0048/N1224). Note changed resolution of issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#38">38</a>. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#196">196</a>
to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#198">198</a>. Closed issues list split into "defects" and
"closed" documents.  Changed the proposed resolution of issue
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#4">4</a> to NAD, and changed the wording of proposed resolution
of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#38">38</a>.
</li>
<li>R10: 
pre-Kona updated.  Added proposed resolutions <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#86">86</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#91">91</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#92">92</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a>. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#190">190</a> to
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#195">195</a>. (99-0033/D1209, 14 Oct 99)
</li>
<li>R9: 
pre-Kona mailing.  Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#140">140</a> to
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#189">189</a>. Issues list split into separate "active" and
"closed" documents. (99-0030/N1206, 25 Aug 99)
</li>
<li>R8: 
post-Dublin mailing. Updated to reflect LWG and full committee actions
in Dublin. (99-0016/N1193, 21 Apr 99)
</li>
<li>R7: 
pre-Dublin updated: Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#130">130</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#131">131</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#132">132</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#133">133</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#134">134</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#135">135</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#136">136</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#137">137</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#138">138</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#139">139</a> (31 Mar 99)
</li>
<li>R6: 
pre-Dublin mailing. Added issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#127">127</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#128">128</a>,
and <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#129">129</a>.  (99-0007/N1194, 22 Feb 99)
</li>
<li>R5: 
update issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>; added issues
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#114">114</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#126">126</a>. Format revisions to prepare
for making list public. (30 Dec 98)
</li>
<li>R4: 
post-Santa Cruz II updated: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#110">110</a>,
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#111">111</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#112">112</a>, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#113">113</a> added, several
issues corrected. (22 Oct 98)
</li>
<li>R3: 
post-Santa Cruz II: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#94">94</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#109">109</a>
added, many issues updated to reflect LWG consensus (12 Oct 98)
</li>
<li>R2: 
pre-Santa Cruz II: Issues <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#73">73</a> to <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#93">93</a> added,
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#17">17</a> updated. (29 Sep 98)
</li>
<li>R1: 
Correction to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#55">55</a> resolution, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#60">60</a> code
format, <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#64">64</a> title. (17 Sep 98)
</li>
</ul>
<h2>Defect Reports</h2>
<hr>
<a name="1"><h3>1.&nbsp;C library linkage editing oversight</h3></a><p><b>Section:</b>&nbsp;17.4.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.using.linkage"> [lib.using.linkage]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;16 Nov 1997</p>
<p>The change specified in the proposed resolution below did not make
it into the Standard. This change was accepted in principle at the
London meeting, and the exact wording below was accepted at the
Morristown meeting.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 17.4.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.using.linkage"> [lib.using.linkage]</a> paragraph 2
from:</p>

<blockquote>
  <p>It is unspecified whether a name from the Standard C library
  declared with external linkage has either extern "C" or
  extern "C++" linkage.</p>
</blockquote>

<p>to:</p>

<blockquote>
  <p>Whether a name from the Standard C library declared with external
  linkage has extern "C" or extern "C++" linkage
  is implementation defined. It is recommended that an implementation
  use extern "C++" linkage for this purpose.</p>
</blockquote>
<hr>
<a name="3"><h3>3.&nbsp;Atexit registration during atexit() call is not described</h3></a><p><b>Section:</b>&nbsp;18.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.cstdint"> [lib.cstdint]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;12 Dec 1997</p>
<p>We appear not to have covered all the possibilities of
 exit processing with respect to
atexit registration. <br>
<br>
Example 1: (C and C++)</p>

<pre>    #include &lt;stdlib.h&gt;
    void f1() { }
    void f2() { atexit(f1); }
    
    int main()
    {
        atexit(f2); // the only use of f2
        return 0; // for C compatibility
    }</pre>

<p>At program exit, f2 gets called due to its registration in
main. Running f2 causes f1 to be newly registered during the exit
processing. Is this a valid program? If so, what are its
semantics?</p>

<p>
Interestingly, neither the C standard, nor the C++ draft standard nor
the forthcoming C9X Committee Draft says directly whether you can
register a function with atexit during exit processing.</p>

<p>
All 3 standards say that functions are run in reverse order of their
registration. Since f1 is registered last, it ought to be run first,
but by the time it is registered, it is too late to be first.</p>

<p>If the program is valid, the standards are self-contradictory about
its semantics.</p>

<p>Example 2: (C++ only)</p>

<pre>    
    void F() { static T t; } // type T has a destructor

    int main()
    {
        atexit(F); // the only use of F
    }
</pre>

<p>Function F registered with atexit has a local static variable t,
and F is called for the first time during exit processing. A local
static object is initialized the first time control flow passes
through its definition, and all static objects are destroyed during
exit processing. Is the code valid? If so, what are its semantics?</p>

<p>
Section 18.3 "Start and termination" says that if a function
F is registered with atexit before a static object t is initialized, F
will not be called until after t's destructor completes.</p>

<p>
In example 2, function F is registered with atexit before its local
static object O could possibly be initialized. On that basis, it must
not be called by exit processing until after O's destructor
completes. But the destructor cannot be run until after F is called,
since otherwise the object could not be constructed in the first
place.</p>

<p>If the program is valid, the standard is self-contradictory about
its semantics.</p>

<p>I plan to submit Example 1 as a public comment on the C9X CD, with
a recommendation that the results be undefined. (Alternative: make it
unspecified. I don't think it is worthwhile to specify the case where
f1 itself registers additional functions, each of which registers
still more functions.)</p>

<p>I think we should resolve the situation in the whatever way the C
committee decides. </p>

<p>For Example 2, I recommend we declare the results undefined.</p>

<p><i>[See reflector message lib-6500 for further discussion.]</i></p>

<p><b>Proposed resolution:</b></p>
<p>Change section 18.3/8 from:</p>
<blockquote>
  First, objects with static storage duration are destroyed and
  functions registered by calling atexit are called. Objects with
  static storage duration are destroyed in the reverse order of the
  completion of their constructor.  (Automatic objects are not
  destroyed as a result of calling exit().) Functions registered with
  atexit are called in the reverse order of their registration.  A
  function registered with atexit before an object obj1 of static
  storage duration is initialized will not be called until obj1's
  destruction has completed. A function registered with atexit after
  an object obj2 of static storage duration is initialized will be
  called before obj2's destruction starts.
</blockquote>
<p>to:</p>
<blockquote>
  First, objects with static storage duration are destroyed and
  functions registered by calling atexit are called. Non-local objects
  with static storage duration are destroyed in the reverse order of
  the completion of their constructor. (Automatic objects are not
  destroyed as a result of calling exit().) Functions registered with
  atexit are called in the reverse order of their registration, except
  that a function is called after any previously registered functions
  that had already been called at the time it was registered. A
  function registered with atexit before a non-local object obj1 of
  static storage duration is initialized will not be called until
  obj1's destruction has completed. A function registered with atexit
  after a non-local object obj2 of static storage duration is
  initialized will be called before obj2's destruction starts. A local
  static object obj3 is destroyed at the same time it would be if a
  function calling the obj3 destructor were registered with atexit at
  the completion of the obj3 constructor.
</blockquote>
<p><b>Rationale:</b></p>
<p>See 99-0039/N1215, October 22, 1999, by Stephen D. Clamage for the analysis
supporting to the proposed resolution.</p>
<hr>
<a name="5"><h3>5.&nbsp;String::compare specification questionable</h3></a><p><b>Section:</b>&nbsp;21.3.6.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::compare"> [lib.string::compare]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Jack Reeves&nbsp; <b>Date:</b>&nbsp;11 Dec 1997</p>
<p>At the very end of the basic_string class definition is the signature: int
compare(size_type pos1, size_type n1, const charT* s, size_type n2 = npos) const; In the
following text this is defined as: returns
basic_string&lt;charT,traits,Allocator&gt;(*this,pos1,n1).compare(
basic_string&lt;charT,traits,Allocator&gt;(s,n2); </p>

<p>Since the constructor basic_string(const charT* s, size_type n, const Allocator&amp; a
= Allocator()) clearly requires that s != NULL and n &lt; npos and further states that it
throws length_error if n == npos, it appears the compare() signature above should always
throw length error if invoked like so: str.compare(1, str.size()-1, s); where 's' is some
null terminated character array. </p>

<p>This appears to be a typo since the obvious intent is to allow either the call above or
something like: str.compare(1, str.size()-1, s, strlen(s)-1); </p>

<p>This would imply that what was really intended was two signatures int compare(size_type
pos1, size_type n1, const charT* s) const int compare(size_type pos1, size_type n1, const
charT* s, size_type n2) const; each defined in terms of the corresponding constructor. </p>
<p><b>Proposed resolution:</b></p>
<p>Replace the compare signature in 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>
(at the very end of the basic_string synopsis) which reads:</p>

<blockquote>
  <p><tt>int compare(size_type pos1, size_type n1,<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; const charT* s,
  size_type n2 = npos) const;</tt></p>
</blockquote>

<p>with:</p>

<blockquote>
  <p><tt>int compare(size_type pos1, size_type n1,<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; const charT* s) const;<br>
  int compare(size_type pos1, size_type n1,<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; const charT* s,
  size_type n2) const;</tt></p>
</blockquote>

<p>Replace the portion of 21.3.6.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::compare"> [lib.string::compare]</a>
paragraphs 5 and 6 which read:</p>

<blockquote>
  <p><tt>int compare(size_type pos, size_type n1,<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; charT * s, size_type n2
  = npos) const;<br>
  </tt>Returns:<tt><br>
  basic_string&lt;charT,traits,Allocator&gt;(*this, pos, n1).compare(<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
  basic_string&lt;charT,traits,Allocator&gt;( s, n2))</tt></p>
</blockquote>

<p>with:</p>

<blockquote>
  <p><tt>int compare(size_type pos, size_type n1,<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; const charT * s) const;<br>
  </tt>Returns:<tt><br>
  basic_string&lt;charT,traits,Allocator&gt;(*this, pos, n1).compare(<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
  basic_string&lt;charT,traits,Allocator&gt;( s ))<br>
  <br>
  int compare(size_type pos, size_type n1,<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; const charT * s,
  size_type n2) const;<br>
  </tt>Returns:<tt><br>
  basic_string&lt;charT,traits,Allocator&gt;(*this, pos, n1).compare(<br>
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
  basic_string&lt;charT,traits,Allocator&gt;( s, n2))</tt></p>
</blockquote>

<p>Editors please note that in addition to splitting the signature, the third argument
becomes const, matching the existing synopsis.</p>
<p><b>Rationale:</b></p>
<p>While the LWG dislikes adding signatures, this is a clear defect in
the Standard which must be fixed.&nbsp; The same problem was also
identified in issues 7 (item 5) and 87.</p>
<hr>
<a name="7"><h3>7.&nbsp;String clause minor problems</h3></a><p><b>Section:</b>&nbsp;21 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.strings"> [lib.strings]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;15 Dec 1997</p>
<p>(1) In 21.3.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::insert"> [lib.string::insert]</a>, the description of template
&lt;class InputIterator&gt; insert(iterator, InputIterator,
InputIterator) makes no sense. It refers to a member function that
doesn't exist. It also talks about the return value of a void
function. </p>

<p>(2) Several versions of basic_string::replace don't appear in the
class synopsis. </p>

<p>(3) basic_string::push_back appears in the synopsis, but is never
described elsewhere.  In the synopsis its argument is const charT,
which doesn't makes much sense; it should probably be charT, or
possible const charT&amp;. </p>

<p>(4) basic_string::pop_back is missing. </p>

<p>(5) int compare(size_type pos, size_type n1, charT* s, size_type n2
= npos) make no sense. First, it's const charT* in the synopsis and
charT* in the description. Second, given what it says in RETURNS,
leaving out the final argument will always result in an exception
getting thrown. This is paragraphs 5 and 6 of 
21.3.6.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::compare"> [lib.string::compare]</a></p>

<p>(6) In table 37, in section 21.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.char.traits.require"> [lib.char.traits.require]</a>,
there's a note for X::move(s, p, n). It says "Copies correctly
even where p is in [s, s+n)". This is correct as far as it goes,
but it doesn't go far enough; it should also guarantee that the copy
is correct even where s in in [p, p+n). These are two orthogonal
guarantees, and neither one follows from the other. Both guarantees
are necessary if X::move is supposed to have the same sort of
semantics as memmove (which was clearly the intent), and both
guarantees are necessary if X::move is actually supposed to be
useful. </p>
<p><b>Proposed resolution:</b></p>
<p>ITEM 1: In 21.3.5.4 [lib.string::insert], change paragraph 16 to <br>
<br>
&nbsp;&nbsp;&nbsp; EFFECTS: Equivalent to insert(p - begin(), basic_string(first, last)).<br>
<br>
ITEM 2:&nbsp; Not a defect; the Standard is clear.. There are ten versions of replace() in
the synopsis, and ten versions in 21.3.5.6 [lib.string::replace].<br>
<br>
ITEM 3: Change the declaration of push_back in the string synopsis (21.3,
[lib.basic.string]) from:</p>

<p>&nbsp;&nbsp;&nbsp;&nbsp; void push_back(const charT)<br>
<br>
to<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp; void push_back(charT)<br>
<br>
Add the following text immediately after 21.3.5.2 [lib.string::append], paragraph 10.<br>
<br>
&nbsp;&nbsp;&nbsp; void basic_string::push_back(charT c);<br>
&nbsp;&nbsp;&nbsp; EFFECTS: Equivalent to append(static_cast&lt;size_type&gt;(1), c);<br>
<br>
ITEM 4: Not a defect. The omission appears to have been deliberate.<br>
<br>
ITEM 5: Duplicate; see issue 5 (and 87).<br>
<br>
ITEM 6: In table 37, Replace:<br>
<br>
&nbsp;&nbsp;&nbsp; "Copies correctly even where p is in [s, s+n)."<br>
<br>
with:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp; "Copies correctly even where the ranges [p, p+n) and [s,
s+n) overlap."</p>
<hr>
<a name="8"><h3>8.&nbsp;Locale::global lacks guarantee</h3></a><p><b>Section:</b>&nbsp;22.1.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.statics"> [lib.locale.statics]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;24 Dec 1997</p>
<p>It appears there's an important guarantee missing from clause
22. We're told that invoking locale::global(L) sets the C locale if L
has a name. However, we're not told whether or not invoking
setlocale(s) sets the global C++ locale. </p>

<p>The intent, I think, is that it should not, but I can't find any
such words anywhere. </p>
<p><b>Proposed resolution:</b></p>
<p>Add a sentence at the end of 22.1.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.statics"> [lib.locale.statics]</a>,
paragraph 2:&nbsp; </p>

<blockquote>
  <p>No library function other than <tt>locale::global()</tt> shall affect 
  the value returned by <tt>locale()</tt>. </p>

</blockquote>
<hr>
<a name="9"><h3>9.&nbsp;Operator new(0) calls should not yield the same pointer</h3></a><p><b>Section:</b>&nbsp;18.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete"> [lib.new.delete]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;4 Jan 1998</p>
<p>Scott Meyers, in a comp.std.c++ posting: I just noticed that
section 3.7.3.1 of CD2 seems to allow for the possibility that all
calls to operator new(0) yield the same pointer, an implementation
technique specifically prohibited by ARM 5.3.3.Was this prohibition
really lifted? Does the FDIS agree with CD2 in the regard? [Issues
list maintainer's note: the IS is the same.]</p>
<p><b>Proposed resolution:</b></p>
<p>Change the last paragraph of 3.7.3 from:</p>
<blockquote>
  <p>Any allocation and/or deallocation functions defined in a C++ program shall
  conform to the semantics specified in 3.7.3.1 and 3.7.3.2.</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>Any allocation and/or deallocation functions defined in a C++ program,
  including the default versions in the library, shall conform to the semantics
  specified in 3.7.3.1 and 3.7.3.2.</p>
</blockquote>
<p>Change 3.7.3.1/2, next-to-last sentence, from :</p>
<blockquote>
  <p>If the size of the space requested is zero, the value returned shall not be
  a null pointer value (4.10).</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>Even if the size of the space requested is zero, the request can fail. If
  the request succeeds, the value returned shall be a non-null pointer value
  (4.10) p0 different from any previously returned value p1, unless that value
  p1 was since passed to an operator delete.</p>
</blockquote>
<p>5.3.4/7 currently reads:</p>
<blockquote>
  <p>When the value of the expression in a direct-new-declarator is zero, the
  allocation function is called to allocate an array with no elements. The
  pointer returned by the new-expression is non-null. [Note: If the library
  allocation function is called, the pointer returned is distinct from the
  pointer to any other object.]</p>
</blockquote>
<p>Retain the first sentence, and delete the remainder.</p>
<p>18.5.1 currently has no text. Add the following:</p>
<blockquote>
  <p>Except where otherwise specified, the provisions of 3.7.3 apply to the
  library versions of operator new and operator delete.</p>
</blockquote>
<p>To 18.5.1.3, add the following text:</p>
<blockquote>
  <p>The provisions of 3.7.3 do not apply to these reserved placement forms of
  operator new and operator delete.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>See 99-0040/N1216, October 22, 1999, by Stephen D. Clamage for the analysis
supporting to the proposed resolution.</p>
<hr>
<a name="11"><h3>11.&nbsp;Bitset minor problems</h3></a><p><b>Section:</b>&nbsp;23.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.template.bitset"> [lib.template.bitset]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;22 Jan 1998</p>
<p>(1) bitset&lt;&gt;::operator[] is mentioned in the class synopsis (23.3.5), but it is
not documented in 23.3.5.2. </p>

<p>(2) The class synopsis only gives a single signature for bitset&lt;&gt;::operator[],
reference operator[](size_t pos). This doesn't make much sense. It ought to be overloaded
on const. reference operator[](size_t pos); bool operator[](size_t pos) const. </p>

<p>(3) Bitset's stream input function (23.3.5.3) ought to skip all whitespace before
trying to extract 0s and 1s. The standard doesn't explicitly say that, though. This should
go in the Effects clause.</p>
<p><b>Proposed resolution:</b></p>
<p>ITEMS 1 AND 2:<br>
<br>
In the bitset synopsis (23.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.template.bitset"> [lib.template.bitset]</a>), 
replace the member function <br>
<br>
<tt>&nbsp;&nbsp;&nbsp; reference operator[](size_t pos);<br>
</tt><br>
with the two member functions<br>
<br>
<tt>&nbsp;&nbsp;&nbsp; bool operator[](size_t pos) const; <br>
&nbsp;&nbsp;&nbsp; reference operator[](size_t pos); <br>
</tt><br>
Add the following text at the end of 23.3.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.members"> [lib.bitset.members]</a>, 
immediately after paragraph 45:</p>

<blockquote>
  <p><tt>bool operator[](size_t pos) const;</tt><br>
  Requires: pos is valid<br>
  Throws: nothing<br>
  Returns: <tt>test(pos)</tt><br>
  <br>
  <tt>bitset&lt;N&gt;::reference operator[](size_t pos);</tt> <br>
  Requires: pos is valid<br>
  Throws: nothing<br>
  Returns: An object of type <tt>bitset&lt;N&gt;::reference</tt> such that <tt>(*this)[pos]
  == this-&gt;test(pos)</tt>, and such that <tt>(*this)[pos] = val</tt> is equivalent to <tt>this-&gt;set(pos,
  val);</tt></p>
</blockquote>
<p><b>Rationale:</b></p>
<p>The LWG believes Item 3 is not a defect. "Formatted
input" implies the desired semantics. See 27.6.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted"> [lib.istream.formatted]</a>.
</p>
<hr>
<a name="13"><h3>13.&nbsp;Eos refuses to die</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;William M. Miller&nbsp; <b>Date:</b>&nbsp;3 Mar 1998</p>
<p>In 27.6.1.2.3, there is a reference to "eos", which is
the only one in the whole draft (at least using Acrobat search), so
it's undefined. </p>
<p><b>Proposed resolution:</b></p>
<p>In 27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>, replace "eos" with
"charT()"</p>
<hr>
<a name="14"><h3>14.&nbsp;Locale::combine should be const</h3></a><p><b>Section:</b>&nbsp;22.1.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.members"> [lib.locale.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>locale::combine is the only member function of locale (other than constructors and
destructor) that is not const. There is no reason for it not to be const, and good reasons
why it should have been const. Furthermore, leaving it non-const conflicts with 22.1.1
paragraph 6: "An instance of a locale is immutable." </p>

<p>History: this member function originally was a constructor. it happened that the
interface it specified had no corresponding language syntax, so it was changed to a member
function. As constructors are never const, there was no "const" in the interface
which was transformed into member "combine". It should have been added at that
time, but the omission was not noticed. </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a> and also in 22.1.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.members"> [lib.locale.members]</a>, add 
"const" to the declaration of member combine: </p>
<blockquote>
  <pre>template &lt;class Facet&gt; locale combine(const locale&amp; other) const; </pre>
</blockquote>
<hr>
<a name="15"><h3>15.&nbsp;Locale::name requirement inconsistent</h3></a><p><b>Section:</b>&nbsp;22.1.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.members"> [lib.locale.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>locale::name() is described as returning a string that can be passed to a locale
constructor, but there is no matching constructor. </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.1.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.members"> [lib.locale.members]</a>, paragraph 5, replace
"<tt>locale(name())</tt>" with
"<tt>locale(name().c_str())</tt>".
</p>
<hr>
<a name="16"><h3>16.&nbsp;Bad ctype_byname&lt;char&gt; decl</h3></a><p><b>Section:</b>&nbsp;22.2.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt"> [lib.locale.codecvt]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The new virtual members ctype_byname&lt;char&gt;::do_widen and do_narrow did not get
edited in properly. Instead, the member do_widen appears four times, with wrong argument
lists. </p>
<p><b>Proposed resolution:</b></p>
<p>The correct declarations for the overloaded members
<tt>do_narrow</tt> and <tt>do_widen</tt> should be copied 
from 22.2.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.special"> [lib.facet.ctype.special]</a>.</p>
<hr>
<a name="17"><h3>17.&nbsp;Bad bool parsing</h3></a><p><b>Section:</b>&nbsp;22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>This section describes the process of parsing a text boolean value from the input
stream. It does not say it recognizes either of the sequences "true" or
"false" and returns the corresponding bool value; instead, it says it recognizes
only one of those sequences, and chooses which according to the received value of a
reference argument intended for returning the result, and reports an error if the other
sequence is found. (!) Furthermore, it claims to get the names from the ctype&lt;&gt;
facet rather than the numpunct&lt;&gt; facet, and it examines the "boolalpha"
flag wrongly; it doesn't define the value "loc"; and finally, it computes
wrongly whether to use numeric or "alpha" parsing.<br>
<br>
I believe the correct algorithm is "as if": </p>

<pre>  // in, err, val, and str are arguments.
  err = 0;
  const numpunct&lt;charT&gt;&amp; np = use_facet&lt;numpunct&lt;charT&gt; &gt;(str.getloc());
  const string_type t = np.truename(), f = np.falsename();
  bool tm = true, fm = true;
  size_t pos = 0;
  while (tm &amp;&amp; pos &lt; t.size() || fm &amp;&amp; pos &lt; f.size()) {
    if (in == end) { err = str.eofbit; }
    bool matched = false;
    if (tm &amp;&amp; pos &lt; t.size()) {
      if (!err &amp;&amp; t[pos] == *in) matched = true;
      else tm = false;
    }
    if (fm &amp;&amp; pos &lt; f.size()) {
      if (!err &amp;&amp; f[pos] == *in) matched = true;
      else fm = false;
    }
    if (matched) { ++in; ++pos; }
    if (pos &gt; t.size()) tm = false;
    if (pos &gt; f.size()) fm = false;
  }
  if (tm == fm || pos == 0) { err |= str.failbit; }
  else                      { val = tm; }
  return in;</pre>

<p>Notice this works reasonably when the candidate strings are both empty, or equal, or
when one is a substring of the other. The proposed text below captures the logic of the
code above.</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>, in the first line of paragraph 14,
change "&amp;&amp;" to "&amp;".</p>

<p>Then, replace paragraphs 15 and 16 as follows:</p>

<blockquote>

  <p>Otherwise target sequences are determined "as if" by
  calling the members <tt>falsename()</tt> and
  <tt>truename()</tt> of the facet obtained by
  <tt>use_facet&lt;numpunct&lt;charT&gt;&nbsp;&gt;(str.getloc())</tt>.  
  Successive characters in the range <tt>[in,end)</tt> (see
  [lib.sequence.reqmts]) are obtained and matched against
  corresponding positions in the target sequences only as necessary to
  identify a unique match. The input iterator <tt>in</tt> is
  compared to <tt>end</tt> only when necessary to obtain a
  character. If and only if a target sequence is uniquely matched,
  <tt>val</tt> is set to the corresponding value.</p>

</blockquote>

<blockquote>
  <p>The <tt>in</tt> iterator is always left pointing one position beyond the last character
  successfully matched. If <tt>val</tt> is set, then err is set to <tt>str.goodbit</tt>; or to
  <tt>str.eofbit</tt> if, when seeking another character to match, it is found that
  <tt>(in==end)</tt>. If <tt>val</tt> is not set, then <i>err</i> is set to <tt>str.failbit</tt>; or to
  <tt>(str.failbit|str.eofbit)</tt>if
  the reason for the failure was that <tt>(in==end)</tt>. [Example: for targets
  <tt>true</tt>:"a" and <tt>false</tt>:"abb", the input sequence "a" yields
  <tt>val==true</tt> and <tt>err==str.eofbit</tt>; the input sequence "abc" yields
  <tt>err=str.failbit</tt>, with <tt>in</tt> ending at the 'c' element. For targets
  <tt>true</tt>:"1"
  and <tt>false</tt>:"0", the input sequence "1" yields <tt>val==true</tt>
  and <tt>err=str.goodbit</tt>. For empty targets (""), any input sequence yields
  <tt>err==str.failbit</tt>. --end example]</p>
</blockquote>
<hr>
<a name="18"><h3>18.&nbsp;Get(...bool&amp;) omitted</h3></a><p><b>Section:</b>&nbsp;22.2.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.members"> [lib.facet.num.get.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In the list of num_get&lt;&gt; non-virtual members on page 22-23, the member
that parses bool values was omitted from the list of definitions of non-virtual
members, though it is listed in the class definition and the corresponding
virtual is listed everywhere appropriate. </p>
<p><b>Proposed resolution:</b></p>
<p>Add at the beginning of 22.2.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.members"> [lib.facet.num.get.members]</a>
another get member for bool&amp;, copied from the entry in 
22.2.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.num.get"> [lib.locale.num.get]</a>.</p>
<hr>
<a name="19"><h3>19.&nbsp;"Noconv" definition too vague</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>
In the definitions of codecvt&lt;&gt;::do_out and do_in, they are
specified to return noconv if "no conversion is
needed". This definition is too vague, and does not say
normatively what is done with the buffers.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the entry for noconv in the table under paragraph 4 in section 
<font color="red">22.2.1.5.2</font> to read:
</p>
<blockquote>
  <p><tt>noconv</tt>: <tt>internT</tt> and <tt>externT</tt> are the same type,
  and input sequence is identical to converted sequence.</p>
</blockquote>
<p>Change the Note in paragraph 2 to normative text as follows:</p>
<blockquote>
  <p>If returns <tt>noconv</tt>, <tt>internT</tt> and <tt>externT</tt> are the
  same type and the converted sequence is identical to the input sequence <tt>[from,from_next)</tt>.
  <tt>to_next</tt> is set equal to <tt>to</tt>, the value of <tt>state</tt> is
  unchanged, and there are no changes to the values in <tt>[to, to_limit)</tt>.</p>
</blockquote>
<hr>
<a name="20"></a><h3><a name="20">20.&nbsp;Thousands_sep returns wrong type</a></h3><p><b>Section:</b>&nbsp;22.2.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.numpunct.virtuals"> [lib.facet.numpunct.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The synopsis for numpunct&lt;&gt;::do_thousands_sep, and the
definition of numpunct&lt;&gt;::thousands_sep which calls it, specify
that it returns a value of type char_type. Here it is erroneously
described as returning a "string_type". </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.numpunct.virtuals"> [lib.facet.numpunct.virtuals]</a>, above paragraph 2, change 
"string_type" to "char_type". </p>
<hr>
<a name="21"><h3>21.&nbsp;Codecvt_byname&lt;&gt; instantiations</h3></a><p><b>Section:</b>&nbsp;22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In the second table in the section, captioned "Required
instantiations", the instantiations for codecvt_byname&lt;&gt;
have been omitted. These are necessary to allow users to construct a
locale by name from facets. </p>
<p><b>Proposed resolution:</b></p>
<p>Add in 22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a> to the table captioned
"Required instantiations", in the category "ctype"
the lines </p>

<blockquote>
  <pre>codecvt_byname&lt;char,char,mbstate_t&gt;,
codecvt_byname&lt;wchar_t,char,mbstate_t&gt; </pre>
</blockquote>
<hr>
<a name="22"><h3>22.&nbsp;Member open vs. flags</h3></a><p><b>Section:</b>&nbsp;27.8.1.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ifstream.members"> [lib.ifstream.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The description of basic_istream&lt;&gt;::open leaves unanswered questions about how it
responds to or changes flags in the error status for the stream. A strict reading
indicates that it ignores the bits and does not change them, which confuses users who do
not expect eofbit and failbit to remain set after a successful open. There are three
reasonable resolutions: 1) status quo 2) fail if fail(), ignore eofbit 3) clear failbit
and eofbit on call to open(). </p>
<p><b>Proposed resolution:</b></p>
<p>In 27.8.1.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ifstream.members"> [lib.ifstream.members]</a> paragraph 3, <i>and</i> in 27.8.1.10 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ofstream.members"> [lib.ofstream.members]</a> paragraph 3, under open() effects, add a footnote:
</p>

<blockquote>
  <p>A successful open does not change the error state.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>This may seem surprising to some users, but it's just an instance
of a general rule: error flags are never cleared by the
implementation. The only way error flags are are ever cleared is if
the user explicitly clears them by hand.</p>

<p>The LWG believed that preserving this general rule was
important enough so that an exception shouldn't be made just for this
one case.  The resolution of this issue clarifies what the LWG
believes to have been the original intent.</p>

<hr>
<a name="24"><h3>24.&nbsp;"do_convert" doesn't exist</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The description of codecvt&lt;&gt;::do_out and do_in mentions a
symbol "do_convert" which is not defined in the
standard. This is a leftover from an edit, and should be "do_in
and do_out". </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>, paragraph 3, change
"do_convert" to "do_in or do_out". Also, in <font color="red">22.2.1.5.2</font>, change "do_convert()" to "do_in
or do_out". </p>
<hr>
<a name="25"><h3>25.&nbsp;String operator&lt;&lt; uses width() value wrong</h3></a><p><b>Section:</b>&nbsp;21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In the description of operator&lt;&lt; applied to strings, the standard says that uses
the smaller of os.width() and str.size(), to pad "as described in stage 3"
elsewhere; but this is inconsistent, as this allows no possibility of space for padding. </p>
<p><b>Proposed resolution:</b></p>
<p>Change 21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>  paragraph 4 from:<br>
<br>
&nbsp;&nbsp;&nbsp; "... where <tt>n</tt> is the smaller of <tt>os.width()</tt> and <tt>str.size()</tt>;
..."<br>
<br>
to: <br>
<br>
&nbsp;&nbsp;&nbsp; "... where <tt>n</tt> is the larger of <tt>os.width()</tt> and <tt>str.size()</tt>;
..."</p>
<hr>
<a name="26"><h3>26.&nbsp;Bad sentry example</h3></a><p><b>Section:</b>&nbsp;27.6.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::sentry"> [lib.istream::sentry]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In paragraph 6, the code in the example: </p>

<pre>  template &lt;class charT, class traits = char_traits&lt;charT&gt; &gt;
  basic_istream&lt;charT,traits&gt;::sentry(
           basic_istream&lt;charT,traits&gt;&amp; is, bool noskipws = false) {
      ...
      int_type c;
      typedef ctype&lt;charT&gt; ctype_type;
      const ctype_type&amp; ctype = use_facet&lt;ctype_type&gt;(is.getloc());
      while ((c = is.rdbuf()-&gt;snextc()) != traits::eof()) {
        if (ctype.is(ctype.space,c)==0) {
          is.rdbuf()-&gt;sputbackc (c);
          break;
        }
      }
      ...
   }</pre>

<p>fails to demonstrate correct use of the facilities described. In
particular, it fails to use traits operators, and specifies incorrect
semantics. (E.g. it specifies skipping over the first character in the
sequence without examining it.) </p>
<p><b>Proposed resolution:</b></p>
<p>Remove the example above from 27.6.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::sentry"> [lib.istream::sentry]</a>
paragraph 6.</p>
<p><b>Rationale:</b></p>
<p>The originally proposed replacement code for the example was not
correct. The LWG tried in Kona and again in Tokyo to correct it
without success. In Tokyo, an implementor reported that actual working
code ran over one page in length and was quite complicated. The LWG
decided that it would be counter-productive to include such a lengthy
example, which might well still contain errors.</p>
<hr>
<a name="27"><h3>27.&nbsp;String::erase(range) yields wrong iterator</h3></a><p><b>Section:</b>&nbsp;21.3.5.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::erase"> [lib.string::erase]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The string::erase(iterator first, iterator last) is specified to return an element one
place beyond the next element after the last one erased. E.g. for the string
"abcde", erasing the range ['b'..'d') would yield an iterator for element 'e',
while 'd' has not been erased. </p>
<p><b>Proposed resolution:</b></p>
<p>In 21.3.5.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::erase"> [lib.string::erase]</a>, paragraph 10, change: </p>

<blockquote>
  <p>Returns: an iterator which points to the element immediately following _last_ prior to
  the element being erased. </p>
</blockquote>

<p>to read </p>

<blockquote>
  <p>Returns: an iterator which points to the element pointed to by _last_ prior to the
  other elements being erased. </p>
</blockquote>
<hr>
<a name="28"><h3>28.&nbsp;Ctype&lt;char&gt;is ambiguous</h3></a><p><b>Section:</b>&nbsp;22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The description of the vector form of ctype&lt;char&gt;::is can be interpreted to mean
something very different from what was intended. Paragraph 4 says </p>

<blockquote>
  <p>Effects: The second form, for all *p in the range [low, high), assigns vec[p-low] to
  table()[(unsigned char)*p]. </p>
</blockquote>

<p>This is intended to copy the value indexed from table()[] into the place identified in
vec[]. </p>
<p><b>Proposed resolution:</b></p>
<p>Change 22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a>, paragraph 4, to read </p>

<blockquote>
  <p>Effects: The second form, for all *p in the range [low, high), assigns into vec[p-low]
  the value table()[(unsigned char)*p]. </p>
</blockquote>
<hr>
<a name="29"><h3>29.&nbsp;Ios_base::init doesn't exist</h3></a><p><b>Section:</b>&nbsp;27.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.narrow.stream.objects"> [lib.narrow.stream.objects]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>Sections 27.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.narrow.stream.objects"> [lib.narrow.stream.objects]</a> and 27.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.wide.stream.objects"> [lib.wide.stream.objects]</a> mention
a function ios_base::init, which is not defined. Probably they mean
basic_ios&lt;&gt;::init, defined in 27.4.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.cons"> [lib.basic.ios.cons]</a>,
paragraph 3. </p>
<p><b>Proposed resolution:</b></p>
<p>[R12: modified to include paragraph 5.]</p>

<p>In 27.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.narrow.stream.objects"> [lib.narrow.stream.objects]</a> paragraph 2 and 5, change </p>

<blockquote>
  <p>ios_base::init </p>
</blockquote>

<p>to </p>

<blockquote>
  <p>basic_ios&lt;char&gt;::init </p>
</blockquote>

<p>Also, make a similar change in 27.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.wide.stream.objects"> [lib.wide.stream.objects]</a> except it
should read </p>

<blockquote>
  <p>basic_ios&lt;wchar_t&gt;::init </p>
</blockquote>
<hr>
<a name="30"><h3>30.&nbsp;Wrong header for LC_*</h3></a><p><b>Section:</b>&nbsp;22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>Paragraph 2 implies that the C macros LC_CTYPE etc. are defined in &lt;cctype&gt;,
where they are in fact defined elsewhere to appear in &lt;clocale&gt;. </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>, paragraph 2, change
"&lt;cctype&gt;" to read "&lt;clocale&gt;". </p>
<hr>
<a name="31"><h3>31.&nbsp;Immutable locale values</h3></a><p><b>Section:</b>&nbsp;22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>Paragraph 6, says "An instance of <tt>locale</tt> is
<i>immutable</i>; once a facet reference is obtained from it,
...". This has caused some confusion, because locale variables
are manifestly assignable. </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a> replace paragraph 6</p>

<blockquote>
  <p>An instance of <tt>locale</tt> is immutable; once a facet
  reference is obtained from it, that reference remains usable as long
  as the locale value itself exists.</p>
</blockquote>

<p>with</p>

<blockquote>
  <p>Once a facet reference is obtained from a locale object by
  calling use_facet&lt;&gt;, that reference remains usable, and the
  results from member functions of it may be cached and re-used, as
  long as some locale object refers to that facet.</p>
</blockquote>
<hr>
<a name="32"><h3>32.&nbsp;Pbackfail description inconsistent</h3></a><p><b>Section:</b>&nbsp;27.5.2.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.pback"> [lib.streambuf.virt.pback]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The description of the required state before calling virtual member
basic_streambuf&lt;&gt;::pbackfail requirements is inconsistent with the conditions
described in 27.5.2.2.4 [lib.streambuf.pub.pback] where member sputbackc calls it.
Specifically, the latter says it calls pbackfail if: </p>

<p>&nbsp;&nbsp;&nbsp; traits::eq(c,gptr()[-1]) is false </p>

<p>where pbackfail claims to require: </p>

<p>&nbsp;&nbsp;&nbsp; traits::eq(*gptr(),traits::to_char_type(c)) returns false </p>

<p>It appears that the pbackfail description is wrong. </p>
<p><b>Proposed resolution:</b></p>
<p>In 27.5.2.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.pback"> [lib.streambuf.virt.pback]</a>, paragraph 1, change:</p>

<blockquote>
  <p>"<tt>traits::eq(*gptr(),traits::to_char_type( c))</tt>"</p>
</blockquote>

<p>to </p>

<blockquote>
  <p>"<tt>traits::eq(traits::to_char_type(c),gptr()[-1])</tt>"
  </p>
</blockquote>
<p><b>Rationale:</b></p>
<p>Note deliberate reordering of arguments for clarity in addition to the correction of
the argument value.</p>
<hr>
<a name="33"><h3>33.&nbsp;Codecvt&lt;&gt; mentions from_type</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In the table defining the results from do_out and do_in, the specification for the
result <i>error</i> says </p>

<blockquote>
  <p>encountered a from_type character it could not convert </p>
</blockquote>

<p>but from_type is not defined. This clearly is intended to be an externT for do_in, or
an internT for do_out. </p>
<p><b>Proposed resolution:</b></p>
<p>In <font color="red">22.2.1.5.2</font> paragraph 4, replace the definition
in the table for the case of _error_ with </p>

<blockquote>
  <p>encountered a character in <tt>[from,from_end)</tt> that it could not convert. </p>
</blockquote>
<hr>
<a name="34"><h3>34.&nbsp;True/falsename() not in ctype&lt;&gt;</h3></a><p><b>Section:</b>&nbsp;22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In paragraph 19, Effects:, members truename() and falsename are used from facet
ctype&lt;charT&gt;, but it has no such members. Note that this is also a problem in
22.2.2.1.2, addressed in (4). </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>, paragraph 19, in the Effects:
clause for member put(...., bool), replace the initialization of the
string_type value s as follows: </p>

<blockquote>
  <pre>const numpunct&amp; np = use_facet&lt;numpunct&lt;charT&gt; &gt;(loc);
string_type s = val ? np.truename() : np.falsename(); </pre>
</blockquote>
<hr>
<a name="35"><h3>35.&nbsp;No manipulator unitbuf in synopsis</h3></a><p><b>Section:</b>&nbsp;27.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostreams.base"> [lib.iostreams.base]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In 27.4.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fmtflags.manip"> [lib.fmtflags.manip]</a>, we have a definition for a manipulator
named "unitbuf". Unlike other manipulators, it's not listed
in synopsis. Similarly for "nounitbuf". </p>
<p><b>Proposed resolution:</b></p>
<p>Add to the synopsis for &lt;ios&gt; in 27.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostreams.base"> [lib.iostreams.base]</a>, after
the entry for "nouppercase", the prototypes: </p>

<blockquote>
  <pre>ios_base&amp; unitbuf(ios_base&amp; str);
ios_base&amp; nounitbuf(ios_base&amp; str); </pre>
</blockquote>
<hr>
<a name="36"><h3>36.&nbsp;Iword &amp; pword storage lifetime omitted</h3></a><p><b>Section:</b>&nbsp;27.4.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.storage"> [lib.ios.base.storage]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In the definitions for ios_base::iword and pword, the lifetime of the storage is
specified badly, so that an implementation which only keeps the last value stored appears
to conform. In particular, it says: </p>

<p>The reference returned may become invalid after another call to the object's iword
member with a different index ... </p>

<p>This is not idle speculation; at least one implementation was done this way. </p>
<p><b>Proposed resolution:</b></p>
<p>Add in 27.4.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.storage"> [lib.ios.base.storage]</a>, in both paragraph 2 and also in
paragraph 4, replace the sentence: </p>

<blockquote>
  <p>The reference returned may become invalid after another call to the object's iword
  [pword] member with a different index, after a call to its copyfmt member, or when the
  object is destroyed. </p>
</blockquote>

<p>with: </p>

<blockquote>
  <p>The reference returned is invalid after any other operations on the object. However,
  the value of the storage referred to is retained, so that until the next call to copyfmt,
  calling iword [pword] with the same index yields another reference to the same value. </p>
</blockquote>

<p>substituting "iword" or "pword" as appropriate. </p>
<hr>
<a name="37"><h3>37.&nbsp;Leftover "global" reference</h3></a><p><b>Section:</b>&nbsp;22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>In the overview of locale semantics, paragraph 4, is the sentence </p>

<blockquote>
  <p>If Facet is not present in a locale (or, failing that, in the global locale), it throws
  the standard exception bad_cast. </p>
</blockquote>

<p>This is not supported by the definition of use_facet&lt;&gt;, and represents semantics
from an old draft. </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a>, paragraph 4, delete the parenthesized
expression </p>

<blockquote>
  <p>(or, failing that, in the global locale) </p>
</blockquote>
<hr>
<a name="38"><h3>38.&nbsp;Facet definition incomplete</h3></a><p><b>Section:</b>&nbsp;22.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.global.templates"> [lib.locale.global.templates]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>It has been noticed by Esa Pulkkinen that the definition of
"facet" is incomplete. In particular, a class derived from
another facet, but which does not define a member <i>id</i>, cannot
safely serve as the argument <i>F</i> to use_facet&lt;F&gt;(loc),
because there is no guarantee that a reference to the facet instance
stored in <i>loc</i> is safely convertible to <i>F</i>. </p>
<p><b>Proposed resolution:</b></p>
<p>In the definition of std::use_facet&lt;&gt;(), replace the text in paragraph 1 which
reads: </p>

<blockquote>
  <p>Get a reference to a facet of a locale. </p>
</blockquote>

<p>with: </p>

<blockquote>
  <p>Requires: <tt>Facet</tt> is a facet class whose definition
  contains the public static member <tt>id</tt> as defined in 22.1.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.facet"> [lib.locale.facet]</a>. </p>
</blockquote>

<p><i>[
Kona: strike as overspecification the text "(not inherits)"
from the original resolution, which read "... whose definition
contains (not inherits) the public static member
<tt>id</tt>..."
]</i></p>

<hr>
<a name="39"><h3>39.&nbsp;istreambuf_iterator&lt;&gt;::operator++(int) definition garbled</h3></a><p><b>Section:</b>&nbsp;24.5.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::op++"> [lib.istreambuf.iterator::op++]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>Following the definition of istreambuf_iterator&lt;&gt;::operator++(int) in paragraph
3, the standard contains three lines of garbage text left over from a previous edit. </p>

<blockquote>
  <pre>istreambuf_iterator&lt;charT,traits&gt; tmp = *this;
sbuf_-&gt;sbumpc();
return(tmp); </pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>In 24.5.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::op++"> [lib.istreambuf.iterator::op++]</a>, delete the three lines of code at the
end of paragraph 3. </p>
<hr>
<a name="40"><h3>40.&nbsp;Meaningless normative paragraph in examples</h3></a><p><b>Section:</b>&nbsp;22.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>Paragraph 3 of the locale examples is a description of part of an
implementation technique that has lost its referent, and doesn't mean
anything. </p>
<p><b>Proposed resolution:</b></p>
<p>Delete 22.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a> paragraph 3 which begins "This
initialization/identification system depends...", or (at the
editor's option) replace it with a place-holder to keep the paragraph
numbering the same. </p>
<hr>
<a name="41"><h3>41.&nbsp;Ios_base needs clear(), exceptions()</h3></a><p><b>Section:</b>&nbsp;27.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The description of ios_base::iword() and pword() in 27.4.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.members.static"> [lib.ios.members.static]</a>, say that if they fail, they "set badbit,
which may throw an exception". However, ios_base offers no
interface to set or to test badbit; those interfaces are defined in
basic_ios&lt;&gt;. </p>
<p><b>Proposed resolution:</b></p>
<p>Change the description in 27.4.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.storage"> [lib.ios.base.storage]</a> in
paragraph 2, and also in paragraph 4, as follows. Replace</p>

<blockquote>
  <p>If the function fails it sets badbit, which may throw an exception.</p>
</blockquote>

<p>with</p>

<blockquote>
  <p>If the function fails, and <tt>*this</tt> is a base sub-object of
  a <tt>basic_ios&lt;&gt;</tt> object or sub-object, the effect is
  equivalent to calling <tt>basic_ios&lt;&gt;::setstate(badbit)</tt>
  on the derived object (which may throw <tt>failure</tt>).</p>
</blockquote>

<p><i>[Kona: LWG reviewed wording; setstate(failbit) changed to
setstate(badbit).]</i></p>

<hr>
<a name="42"><h3>42.&nbsp;String ctors specify wrong default allocator</h3></a><p><b>Section:</b>&nbsp;21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The basic_string&lt;&gt; copy constructor: </p>

<pre>basic_string(const basic_string&amp; str, size_type pos = 0,
             size_type n = npos, const Allocator&amp; a = Allocator()); </pre>

<p>specifies an Allocator argument default value that is
counter-intuitive. The natural choice for a the allocator to copy from
is str.get_allocator(). Though this cannot be expressed in
default-argument notation, overloading suffices. </p>

<p>Alternatively, the other containers in Clause 23 (deque, list,
vector) do not have this form of constructor, so it is inconsistent,
and an evident source of confusion, for basic_string&lt;&gt; to have
it, so it might better be removed. </p>
<p><b>Proposed resolution:</b></p>
<p> In 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>, replace the declaration of the copy
constructor as follows: </p>

<blockquote>
  <pre>basic_string(const basic_string&amp; str);
basic_string(const basic_string&amp; str, size_type pos, size_type n = npos,
             const Allocator&amp; a = Allocator());</pre>
</blockquote>

<p>In 21.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.cons"> [lib.string.cons]</a>, replace the copy constructor declaration
as above. Add to paragraph 5, Effects:</p>

<blockquote>
  <p>In the first form, the Allocator value used is copied from
  <tt>str.get_allocator()</tt>.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>The LWG believes the constructor is actually broken, rather than
just an unfortunate design choice.</p>

<p>The LWG considered two other possible resolutions:</p>

<p>A. In 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>, replace the declaration of the copy
constructor as follows:</p>

<blockquote>
  <pre>basic_string(const basic_string&amp; str, size_type pos = 0,
             size_type n = npos);
basic_string(const basic_string&amp; str, size_type pos,
             size_type n, const Allocator&amp; a); </pre>
</blockquote>

<p>In 21.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.cons"> [lib.string.cons]</a>, replace the copy constructor declaration
as above. Add to paragraph 5, Effects: </p>

<blockquote>
  <p>When no <tt>Allocator</tt> argument is provided, the string is constructed using the
  value <tt>str.get_allocator()</tt>. </p>
</blockquote>

<p>B. In 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>, and also in 21.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.cons"> [lib.string.cons]</a>, replace
the declaration of the copy constructor as follows: </p>

<blockquote>
  <pre>basic_string(const basic_string&amp; str, size_type pos = 0,
             size_type n = npos); </pre>
</blockquote>

<p>The proposed resolution reflects the original intent of the LWG. It
was also noted by Pete Becker that this fix "will cause
a small amount of existing code to now work correctly."</p>

<p><i>[
Kona: issue editing snafu fixed - the proposed resolution now correctly
reflects the LWG consensus.
]</i></p>
<hr>
<a name="44"><h3>44.&nbsp;Iostreams use operator== on int_type values</h3></a><p><b>Section:</b>&nbsp;27 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.input.output"> [lib.input.output]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>Many of the specifications for iostreams specify that character
values or their int_type equivalents are compared using operators ==
or !=, though in other places traits::eq() or traits::eq_int_type is
specified to be used throughout. This is an inconsistency; we should
change uses of == and != to use the traits members instead. </p>
<p><b>Proposed resolution:</b></p>

<p><i>[Pre-Kona: Dietmar supplied wording]</i></p>

<p>List of changes to clause 27:</p>
<ol>
<li>
   In lib.basic.ios.members paragraph 13 (postcondition clause for
   'fill(cT)') change

<blockquote>
     fillch == fill()
</blockquote>

   to

<blockquote>
     traits::eq(fillch, fill())
</blockquote>


</li>
<li>
   In lib.istream.unformatted paragraph 7 (effects clause for
   'get(cT,streamsize,cT)'), third bullet, change

<blockquote>
     c == delim for the next available input character c
</blockquote>

   to

<blockquote>
     traits::eq(c, delim) for the next available input character c
  </blockquote>

</li>
<li>
   In lib.istream.unformatted paragraph 12 (effects clause for
   'get(basic_streambuf&lt;cT,Tr&gt;&amp;,cT)'), third bullet, change

<blockquote>
     c == delim for the next available input character c
</blockquote>

   to

<blockquote>
     traits::eq(c, delim) for the next available input character c
</blockquote>

</li>
<li>
   In lib.istream.unformatted paragraph 17 (effects clause for
   'getline(cT,streamsize,cT)'), second bullet, change

<blockquote>
     c == delim for the next available input character c
</blockquote>

   to

<blockquote>
     traits::eq(c, delim) for the next available input character c
  </blockquote>

</li>
<li>
   In lib.istream.unformatted paragraph 24 (effects clause for
   'ignore(int,int_type)'), second bullet, change

<blockquote>
     c == delim for the next available input character c
</blockquote>

   to

<blockquote>
     traits::eq_int_type(c, delim) for the next available input
     character c
</blockquote>
  
</li>
<li>
   In lib.istream.unformatted paragraph 25 (notes clause for
   'ignore(int,int_type)'), second bullet, change

<blockquote>
     The last condition will never occur if delim == traits::eof()
</blockquote>

   to

<blockquote>
     The last condition will never occur if
     traits::eq_int_type(delim, traits::eof()).
</blockquote>

</li>
<li>
   In lib.istream.sentry paragraph 6 (example implementation for the
   sentry constructor) change

<blockquote>
     while ((c = is.rdbuf()-&gt;snextc()) != traits::eof()) {
</blockquote>

   to

<blockquote>
     while (!traits::eq_int_type(c = is.rdbuf()-&gt;snextc(), traits::eof())) {
</blockquote>

</li>
</ol>

<p>List of changes to Chapter 21:</p>

<ol>
<li>
   In lib.string::find paragraph 1 (effects clause for find()),
   second bullet, change

<blockquote>
     at(xpos+I) == str.at(I) for all elements ...
</blockquote>

   to

<blockquote>
     traits::eq(at(xpos+I), str.at(I)) for all elements ...
</blockquote>

</li>
<li>
   In lib.string::rfind paragraph 1 (effects clause for rfind()),
   second bullet, change

<blockquote>
     at(xpos+I) == str.at(I) for all elements ...
</blockquote>

   to

<blockquote>
     traits::eq(at(xpos+I), str.at(I)) for all elements ...
</blockquote>

</li>
<li>
   In lib.string::find.first.of paragraph 1 (effects clause for
   find_first_of()), second bullet, change

<blockquote>
     at(xpos+I) == str.at(I) for all elements ...
</blockquote>

   to

<blockquote>
     traits::eq(at(xpos+I), str.at(I)) for all elements ...
</blockquote>

</li>
<li>
   In lib.string::find.last.of paragraph 1 (effects clause for
   find_last_of()), second bullet, change

<blockquote>
     at(xpos+I) == str.at(I) for all elements ...
</blockquote>

   to

<blockquote>
     traits::eq(at(xpos+I), str.at(I)) for all elements ...
</blockquote>

</li>
<li>
   In lib.string::find.first.not.of paragraph 1 (effects clause for
   find_first_not_of()), second bullet, change

<blockquote>
     at(xpos+I) == str.at(I) for all elements ...
</blockquote>

   to

<blockquote>
     traits::eq(at(xpos+I), str.at(I)) for all elements ...
</blockquote>
</li>

<li>
   In lib.string::find.last.not.of paragraph 1 (effects clause for
   find_last_not_of()), second bullet, change

<blockquote>
     at(xpos+I) == str.at(I) for all elements ...
</blockquote>

   to

<blockquote>
     traits::eq(at(xpos+I), str.at(I)) for all elements ...
</blockquote>
</li>

<li>
   In lib.string.ios paragraph 5 (effects clause for getline()),
   second bullet, change

<blockquote>
     c == delim for the next available input character c 
</blockquote>

   to

<blockquote>
     traits::eq(c, delim) for the next available input character c 
</blockquote>
</li>

</ol>

<p>Notes:</p>
<ul>
<li>
  Fixing this issue highlights another sloppyness in
  lib.istream.unformatted paragraph 24: this clause mentions a "character"
  which is then compared to an 'int_type' (see item 5. in the list
  below). It is not clear whether this requires explicit words and
  if so what these words are supposed to be. A similar issue exists,
  BTW, for operator*() of istreambuf_iterator which returns the result
  of sgetc() as a character type (see lib.istreambuf.iterator::op*
  paragraph 1), and for operator++() of istreambuf_iterator which
  passes the result of sbumpc() to a constructor taking a char_type
  (see lib.istreambuf.iterator::operator++ paragraph 3). Similarily, the
  assignment operator ostreambuf_iterator passes a char_type to a function
  taking an int_type (see lib.ostreambuf.iter.ops paragraph 1).
</li>
<li>
  It is inconsistent to use comparisons using the traits functions in
  Chapter 27 while not using them in Chapter 21, especially as some
  of the inconsistent uses actually involve streams (eg. getline() on
  streams). To avoid leaving this issue open still longer due to this
  inconsistency (it is open since 1998), a list of changes to Chapter
  21 is below.
</li>
<li>
  In Chapter 24 there are several places with statements like "the end
  of stream is reached (streambuf_type::sgetc() returns traits::eof())"
  (lib.istreambuf.iterator paragraph 1, lib.ostreambuf.iter.ops
  paragraph 5). It is unclear whether these should be clarified to use
  traits::eq_int_type() for detecting traits::eof().
</li>
</ul>

<hr>
<a name="46"><h3>46.&nbsp;Minor Annex D errors</h3></a><p><b>Section:</b>&nbsp;D.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.str.strstreams"> [depr.str.strstreams]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Brendan Kehoe&nbsp; <b>Date:</b>&nbsp; 1 Jun 1998</p>
<p>See lib-6522 and edit-814.</p>
<p><b>Proposed resolution:</b></p>
<p>Change D.7.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf"> [depr.strstreambuf]</a> (since streambuf is a typedef of
basic_streambuf&lt;char&gt;) from:</p>

<pre>         virtual streambuf&lt;char&gt;* setbuf(char* s, streamsize n);</pre>

<p>to:</p>

<pre>         virtual streambuf* setbuf(char* s, streamsize n);</pre>

<p>In D.7.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstream"> [depr.strstream]</a> insert the semicolon now missing after
int_type:</p>

<pre>     namespace std {
       class strstream
         : public basic_iostream&lt;char&gt; {
       public:
         // Types
         typedef char                                char_type;
         typedef typename char_traits&lt;char&gt;::int_type int_type
         typedef typename char_traits&lt;char&gt;::pos_type pos_type;</pre>
<hr>
<a name="47"><h3>47.&nbsp;Imbue() and getloc() Returns clauses swapped</h3></a><p><b>Section:</b>&nbsp;27.4.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.locales"> [lib.ios.base.locales]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;21 Jun 1998</p>
<p>Section 27.4.2.3 specifies how imbue() and getloc() work. That
section has two RETURNS clauses, and they make no sense as
stated. They make perfect sense, though, if you swap them. Am I
correct in thinking that paragraphs 2 and 4 just got mixed up by
accident?</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.4.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.locales"> [lib.ios.base.locales]</a> swap paragraphs 2 and 4.</p>
<hr>
<a name="48"><h3>48.&nbsp;Use of non-existent exception constructor</h3></a><p><b>Section:</b>&nbsp;27.4.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios::failure"> [lib.ios::failure]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;21 Jun 1998</p>
<p>27.4.2.1.1, paragraph 2, says that class failure initializes the
base class, exception, with exception(msg). Class exception (see
18.6.1) has no such constructor.</p>
<p><b>Proposed resolution:</b></p>
<p>Replace 27.4.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios::failure"> [lib.ios::failure]</a>, paragraph 2, with</p>

<blockquote>
  <p>EFFECTS: Constructs an object of class <tt>failure</tt>.</p>
</blockquote>
<hr>
<a name="49"><h3>49.&nbsp;Underspecification of ios_base::sync_with_stdio</h3></a><p><b>Section:</b>&nbsp;27.4.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.members.static"> [lib.ios.members.static]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;21 Jun 1998</p>
<p>Two problems</p>

<p>(1) 27.4.2.4 doesn't say what ios_base::sync_with_stdio(f)
returns. Does it return f, or does it return the previous
synchronization state? My guess is the latter, but the standard
doesn't say so.</p>

<p>(2) 27.4.2.4 doesn't say what it means for streams to be
synchronized with stdio.  Again, of course, I can make some
guesses. (And I'm unhappy about the performance implications of those
guesses, but that's another matter.)</p>
<p><b>Proposed resolution:</b></p>
<p>Change the following sentence in 27.4.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.members.static"> [lib.ios.members.static]</a>
returns clause from:</p>

<blockquote>
  <p><tt>true</tt> if the standard iostream objects (27.3) are
  synchronized and otherwise returns <tt>false</tt>.</p>
</blockquote>

<p>to:</p>

<blockquote>
  <p><tt>true</tt> if the previous state of the standard iostream
  objects (27.3) was synchronized and otherwise returns
  <tt>false</tt>.</p>
</blockquote>

<p>Add the following immediately after 27.4.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.members.static"> [lib.ios.members.static]</a>,
paragraph 2:</p>

<blockquote>
<p>When a standard iostream object str is <i>synchronized</i> with a
standard stdio stream f, the effect of inserting a character c by</p>
<pre>  fputc(f, c);
</pre>

<p>is the same as the effect of</p>
<pre>  str.rdbuf()-&gt;sputc(c);
</pre>

<p>for any sequence of characters; the effect of extracting a
character c by</p>
<pre>  c = fgetc(f);
</pre>

<p>is the same as the effect of:</p>
<pre>  c = str.rdbuf()-&gt;sbumpc(c);
</pre>

<p>for any sequences of characters; and the effect of pushing
back a character c by</p>
<pre>  ungetc(c, f);
</pre>

<p>is the same as the effect of</p>
<pre>  str.rdbuf()-&gt;sputbackc(c);
</pre>

<p>for any sequence of characters.  [<i>Footnote</i>: This implies
that operations on a standard iostream object can be mixed arbitrarily
with operations on the corresponding stdio stream.  In practical
terms, synchronization usually means that a standard iostream object
and a standard stdio object share a buffer. <i>--End Footnote</i>]</p>
</blockquote>

<p><i>[pre-Copenhagen: PJP and Matt contributed the definition
of "synchronization"]</i></p>

<p><i>[post-Copenhagen: proposed resolution was revised slightly:
text was added in the non-normative footnote to say that operations
on the two streams can be mixed arbitrarily.]</i></p>
<hr>
<a name="50"><h3>50.&nbsp;Copy constructor and assignment operator of ios_base</h3></a><p><b>Section:</b>&nbsp;27.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;21 Jun 1998</p>
<p>As written, ios_base has a copy constructor and an assignment
operator. (Nothing in the standard says it doesn't have one, and all
classes have copy constructors and assignment operators unless you
take specific steps to avoid them.) However, nothing in 27.4.2 says
what the copy constructor and assignment operator do. </p>

<p>My guess is that this was an oversight, that ios_base is, like
basic_ios, not supposed to have a copy constructor or an assignment
operator.</p>

<p>
Jerry Schwarz comments: Yes, its an oversight, but in the opposite
sense to what you're suggesting. At one point there was a definite
intention that you could copy ios_base. It's an easy way to save the
entire state of a stream for future use. As you note, to carry out
that intention would have required a explicit description of the
semantics (e.g. what happens to the iarray and parray stuff).
</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a>, class ios_base, specify the copy
constructor and operator= members as being private.</p>
<p><b>Rationale:</b></p>
<p>The LWG believes the difficulty of specifying correct semantics
outweighs any benefit of allowing ios_base objects to be copyable.</p>
<hr>
<a name="51"><h3>51.&nbsp;Requirement to not invalidate iterators missing</h3></a><p><b>Section:</b>&nbsp;23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;David Vandevoorde&nbsp; <b>Date:</b>&nbsp;23 Jun 1998</p>
<p>The std::sort algorithm can in general only sort a given sequence
by moving around values. The list&lt;&gt;::sort() member on the other
hand could move around values or just update internal pointers. Either
method can leave iterators into the list&lt;&gt; dereferencable, but
they would point to different things. </p>

<p>Does the FDIS mandate anywhere which method should be used for
list&lt;&gt;::sort()?</p>

<p>Matt Austern comments:</p>

<p>I think you've found an omission in the standard. </p>

<p>The library working group discussed this point, and there was
supposed to be a general requirement saying that list, set, map,
multiset, and multimap may not invalidate iterators, or change the
values that iterators point to, except when an operation does it
explicitly. So, for example, insert() doesn't invalidate any iterators
and erase() and remove() only invalidate iterators pointing to the
elements that are being erased. </p>

<p>I looked for that general requirement in the FDIS, and, while I
found a limited form of it for the sorted associative containers, I
didn't find it for list. It looks like it just got omitted. </p>

<p>The intention, though, is that list&lt;&gt;::sort does not
invalidate any iterators and does not change the values that any
iterator points to. There would be no reason to have the member
function otherwise.</p>
<p><b>Proposed resolution:</b></p>
<p>Add a new paragraph at the end of 23.1:</p>

<blockquote>
  <p>Unless otherwise specified (either explicitly or by defining a function in terms of
  other functions), invoking a container member function or passing a container as an
  argument to a library function shall not invalidate iterators to, or change the values of,
  objects within that container. </p>
</blockquote>
<p><b>Rationale:</b></p>
<p>This was US issue CD2-23-011; it was accepted in London but the
change was not made due to an editing oversight. The wording in the
proposed resolution below is somewhat updated from CD2-23-011,
particularly the addition of the phrase "or change the values
of"</p>
<hr>
<a name="52"><h3>52.&nbsp;Small I/O problems</h3></a><p><b>Section:</b>&nbsp;27.4.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos.operations"> [lib.fpos.operations]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;23 Jun 1998</p>
<p>First, 27.4.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.cons"> [lib.basic.ios.cons]</a>, table 89. This is pretty obvious:
it should be titled "basic_ios&lt;&gt;() effects", not
"ios_base() effects". </p>

<p>[The second item is a duplicate; see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#6">6</a> for
resolution.]</p>

<p>Second, 27.4.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos.operations"> [lib.fpos.operations]</a> table 88 . There are a couple
different things wrong with it, some of which I've already discussed
with Jerry, but the most obvious mechanical sort of error is that it
uses expressions like P(i) and p(i), without ever defining what sort
of thing "i" is.
</p>

<p>(The other problem is that it requires support for streampos
arithmetic. This is impossible on some systems, i.e. ones where file
position is a complicated structure rather than just a number. Jerry
tells me that the intention was to require syntactic support for
streampos arithmetic, but that it wasn't actually supposed to do
anything meaningful except on platforms, like Unix, where genuine
arithmetic is possible.) </p>
<p><b>Proposed resolution:</b></p>
<p>Change 27.4.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.cons"> [lib.basic.ios.cons]</a> table 89 title from
"ios_base() effects" to "basic_ios&lt;&gt;()
effects". </p>
<hr>
<a name="53"><h3>53.&nbsp;Basic_ios destructor unspecified</h3></a><p><b>Section:</b>&nbsp;27.4.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.cons"> [lib.basic.ios.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;23 Jun 1998</p>
<p>There's nothing in 27.4.4 saying what basic_ios's destructor does.
The important question is whether basic_ios::~basic_ios() destroys
rdbuf().</p>
<p><b>Proposed resolution:</b></p>
<p>Add after 27.4.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.cons"> [lib.basic.ios.cons]</a> paragraph 2:</p>

<blockquote>
  <p><tt>virtual ~basic_ios();</tt></p>
  <p><b>Notes</b>: The destructor does not destroy <tt>rdbuf()</tt>.</p>
</blockquote>
<p><b>Rationale:</b></p> 
<p>The LWG reviewed the additional question of whether or not
<tt>rdbuf(0)</tt> may set <tt>badbit</tt>.  The answer is
clearly yes; it may be set via <tt>clear()</tt>.  See 27.4.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.members"> [lib.basic.ios.members]</a>, paragraph 6.  This issue was reviewed at length
by the LWG, which removed from the original proposed resolution a
footnote which incorrectly said "<tt>rdbuf(0)</tt> does not set
<tt>badbit</tt>".</p>
<hr>
<a name="54"><h3>54.&nbsp;Basic_streambuf's destructor</h3></a><p><b>Section:</b>&nbsp;27.5.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.cons"> [lib.streambuf.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;25 Jun 1998</p>
<p>The class synopsis for basic_streambuf shows a (virtual)
destructor, but the standard doesn't say what that destructor does. My
assumption is that it does nothing, but the standard should say so
explicitly. </p>
<p><b>Proposed resolution:</b></p>
<p>Add after 27.5.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.cons"> [lib.streambuf.cons]</a> paragraph 2:</p>

<blockquote>
  <p><tt>virtual&nbsp; ~basic_streambuf();</tt></p>
  <p><b>Effects</b>: None.</p>
</blockquote>
<hr>
<a name="55"><h3>55.&nbsp;Invalid stream position is undefined</h3></a><p><b>Section:</b>&nbsp;27 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.input.output"> [lib.input.output]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;26 Jun 1998</p>
<p>Several member functions in clause 27 are defined in certain
circumstances to return an "invalid stream position", a term
that is defined nowhere in the standard. Two places (27.5.2.4.2,
paragraph 4, and 27.8.1.4, paragraph 15) contain a cross-reference to
a definition in _lib.iostreams.definitions_, a nonexistent
section. </p>

<p>I suspect that the invalid stream position is just supposed to be
pos_type(-1).  Probably best to say explicitly in (for example)
27.5.2.4.2 that the return value is pos_type(-1), rather than to use
the term "invalid stream position", define that term
somewhere, and then put in a cross-reference. </p>

<p>The phrase "invalid stream position" appears ten times in
the C++ Standard.  In seven places it refers to a return value, and it
should be changed. In three places it refers to an argument, and it
should not be changed. Here are the three places where "invalid
stream position" should not be changed:</p>

<blockquote>
  <p>27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>, paragraph 14<br>
  27.8.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a>, paragraph 14<br>
  D.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a>, paragraph 17
  </p>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>In 27.5.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.buffer"> [lib.streambuf.virt.buffer]</a>, paragraph 4, change "Returns an
object of class pos_type that stores an invalid stream position
(_lib.iostreams.definitions_)" to "Returns
<tt>pos_type(off_type(-1))</tt>".
</p>

<p>In 27.5.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.buffer"> [lib.streambuf.virt.buffer]</a>, paragraph 6, change "Returns
an object of class pos_type that stores an invalid stream
position" to "Returns <tt>pos_type(off_type(-1))</tt>".</p>

<p>In 27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>, paragraph 13, change "the object
stores an invalid stream position" to "the return value is
<tt>pos_type(off_type(-1))</tt>". </p>

<p>In 27.8.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a>, paragraph 13, change "returns an
invalid stream position (27.4.3)" to "returns
<tt>pos_type(off_type(-1))</tt>" </p>

<p>In 27.8.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a>, paragraph 15, change "Otherwise
returns an invalid stream position (_lib.iostreams.definitions_)"
to "Otherwise returns <tt>pos_type(off_type(-1))</tt>"
</p>

<p>In D.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a>, paragraph 15, change "the object
stores an invalid stream position" to "the return value is
<tt>pos_type(off_type(-1))</tt>" </p>

<p>In D.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a>, paragraph 18, change "the object
stores an invalid stream position" to "the return value is
<tt>pos_type(off_type(-1))</tt>"</p>
<hr>
<a name="56"><h3>56.&nbsp;Showmanyc's return type</h3></a><p><b>Section:</b>&nbsp;27.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf"> [lib.streambuf]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;29 Jun 1998</p>
<p>The class summary for basic_streambuf&lt;&gt;, in 27.5.2, says that
showmanyc has return type int. However, 27.5.2.4.3 says that its
return type is streamsize. </p>
<p><b>Proposed resolution:</b></p>
<p>Change <tt>showmanyc</tt>'s return type in the
27.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf"> [lib.streambuf]</a> class summary to <tt>streamsize</tt>.</p>
<hr>
<a name="57"><h3>57.&nbsp;Mistake in char_traits</h3></a><p><b>Section:</b>&nbsp;21.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.char.traits.specializations.wchar.t"> [lib.char.traits.specializations.wchar.t]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;1 Jul 1998</p>
<p>21.1.3.2, paragraph 3, says "The types streampos and
wstreampos may be different if the implementation supports no shift
encoding in narrow-oriented iostreams but supports one or more shift
encodings in wide-oriented streams". </p>

<p>That's wrong: the two are the same type. The &lt;iosfwd&gt; summary
in 27.2 says that streampos and wstreampos are, respectively, synonyms
for fpos&lt;char_traits&lt;char&gt;::state_type&gt; and
fpos&lt;char_traits&lt;wchar_t&gt;::state_type&gt;, and, flipping back
to clause 21, we see in 21.1.3.1 and 21.1.3.2 that
char_traits&lt;char&gt;::state_type and
char_traits&lt;wchar_t&gt;::state_type must both be mbstate_t. </p>
<p><b>Proposed resolution:</b></p>
<p>Remove the sentence in 21.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.char.traits.specializations.wchar.t"> [lib.char.traits.specializations.wchar.t]</a> paragraph 3 which
begins "The types streampos and wstreampos may be
different..." . </p>
<hr>
<a name="59"><h3>59.&nbsp;Ambiguity in specification of gbump</h3></a><p><b>Section:</b>&nbsp;27.5.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.get.area"> [lib.streambuf.get.area]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;28 Jul 1998</p>
<p>27.5.2.3.1 says that basic_streambuf::gbump() "Advances the
next pointer for the input sequence by n." </p>

<p>The straightforward interpretation is that it is just gptr() +=
n. An alternative interpretation, though, is that it behaves as if it
calls sbumpc n times. (The issue, of course, is whether it might ever
call underflow.) There is a similar ambiguity in the case of
pbump. </p>

<p>(The "classic" AT&amp;T implementation used the
former interpretation.)</p>
<p><b>Proposed resolution:</b></p>
<p>Change 27.5.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.get.area"> [lib.streambuf.get.area]</a> paragraph 4 gbump effects from:</p>

<blockquote>
  <p>Effects: Advances the next pointer for the input sequence by n.</p>
</blockquote>

<p>to:</p>

<blockquote>
  <p>Effects: Adds <tt>n</tt> to the next pointer for the input sequence.</p>
</blockquote>

<p>Make the same change to 27.5.2.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.put.area"> [lib.streambuf.put.area]</a> paragraph 4 pbump
effects.</p>
<hr>
<a name="60"><h3>60.&nbsp;What is a formatted input function?</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.reqmts"> [lib.istream.formatted.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;3 Aug 1998</p>
<p>Paragraph 1 of 27.6.1.2.1 contains general requirements for all
formatted input functions. Some of the functions defined in section
27.6.1.2 explicitly say that those requirements apply ("Behaves
like a formatted input member (as described in 27.6.1.2.1)"), but
others don't. The question: is 27.6.1.2.1 supposed to apply to
everything in 27.6.1.2, or only to those member functions that
explicitly say "behaves like a formatted input member"? Or
to put it differently: are we to assume that everything that appears
in a section called "Formatted input functions" really is a
formatted input function? I assume that 27.6.1.2.1 is intended to
apply to the arithmetic extractors (27.6.1.2.2), but I assume that it
is not intended to apply to extractors like </p>

<pre>    basic_istream&amp; operator&gt;&gt;(basic_istream&amp; (*pf)(basic_istream&amp;));</pre>

<p>and </p>

<pre>    basic_istream&amp; operator&gt;&gt;(basic_streammbuf*);</pre>

<p>There is a similar ambiguity for unformatted input, formatted output, and unformatted
output. </p>

<p>Comments from Judy Ward: It seems like the problem is that the
basic_istream and basic_ostream operator &lt;&lt;()'s that are used
for the manipulators and streambuf* are in the wrong section and
should have their own separate section or be modified to make it clear
that the "Common requirements" listed in section 27.6.1.2.1
(for basic_istream) and section 27.6.2.5.1 (for basic_ostream) do not
apply to them. </p>

<p>Additional comments from Dietmar Kühl: It appears to be somewhat
nonsensical to consider the functions defined in 27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a> paragraphs 1 to 5 to be "Formatted input
function" but since these functions are defined in a section
labeled "Formatted input functions" it is unclear to me
whether these operators are considered formatted input functions which
have to conform to the "common requirements" from 27.6.1.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.reqmts"> [lib.istream.formatted.reqmts]</a>: If this is the case, all manipulators, not
just <tt>ws</tt>, would skip whitespace unless <tt>noskipws</tt> is
set (... but setting <tt>noskipws</tt> using the manipulator syntax
would also skip whitespace :-)</p> <p>It is not clear which functions
are to be considered unformatted input functions. As written, it seems
that all functions in 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> are unformatted input
functions. However, it does not really make much sense to construct a
sentry object for <tt>gcount()</tt>, <tt>sync()</tt>, ... Also it is
unclear what happens to the <tt>gcount()</tt> if
eg. <tt>gcount()</tt>, <tt>putback()</tt>, <tt>unget()</tt>, or
<tt>sync()</tt> is called: These functions don't extract characters,
some of them even "unextract" a character. Should this still
be reflected in <tt>gcount()</tt>? Of course, it could be read as if
after a call to <tt>gcount()</tt> <tt>gcount()</tt> return <tt>0</tt>
(the last unformatted input function, <tt>gcount()</tt>, didn't
extract any character) and after a call to <tt>putback()</tt>
<tt>gcount()</tt> returns <tt>-1</tt> (the last unformatted input
function <tt>putback()</tt> did "extract" back into the
stream). Correspondingly for <tt>unget()</tt>. Is this what is
intended?  If so, this should be clarified. Otherwise, a corresponding
clarification should be used.</p>
<p><b>Proposed resolution:</b></p>
<p>
In 27.6.1.2.2 [lib.istream.formatted.arithmetic], paragraph 1.
Change the beginning of the second sentence from "The conversion
occurs" to "These extractors behave as formatted input functions (as
described in 27.6.1.2.1).  After a sentry object is constructed,
the conversion occurs"
</p>

<p>
In 27.6.1.2.3, [lib.istream::extractors], before paragraph 1.
Add an effects clause.  "Effects: None.  This extractor does
not behave as a formatted input function (as described in
27.6.1.2.1).
</p>

<p>
In 27.6.1.2.3, [lib.istream::extractors], paragraph 2.  Change the
effects clause to "Effects: Calls pf(*this).  This extractor does not
behave as a formatted input function (as described in 27.6.1.2.1).
</p>

<p>
In 27.6.1.2.3, [lib.istream::extractors], paragraph 4.  Change the
effects clause to "Effects: Calls pf(*this).  This extractor does not
behave as a formatted input function (as described in 27.6.1.2.1).
</p>

<p>
In 27.6.1.2.3, [lib.istream::extractors], paragraph 12.  Change the
first two sentences from "If sb is null, calls setstate(failbit),
which may throw ios_base::failure (27.4.4.3).  Extracts characters
from *this..." to "Behaves as a formatted input function (as described
in 27.6.1.2.1).  If sb is null, calls setstate(failbit), which may
throw ios_base::failure (27.4.4.3).  After a sentry object is
constructed, extracts characters from *this...".
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], before paragraph 2.  Add an
effects clause.  "Effects: none. This member function does not behave
as an unformatted input function (as described in 27.6.1.3, paragraph 1)."
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 3.  Change the
beginning of the first sentence of the effects clause from "Extracts a
character" to "Behaves as an unformatted input function (as described
in 27.6.1.3, paragraph 1).  After constructing a sentry object, extracts a
character"
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 5.  Change the
beginning of the first sentence of the effects clause from "Extracts a
character" to "Behaves as an unformatted input function (as described
in 27.6.1.3, paragraph 1).  After constructing a sentry object, extracts a
character"
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 7.  Change the
beginning of the first sentence of the effects clause from "Extracts
characters" to "Behaves as an unformatted input function (as described
in 27.6.1.3, paragraph 1).  After constructing a sentry object, extracts
characters"
</p>

<p>
[No change needed in paragraph 10, because it refers to paragraph 7.]
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 12.  Change the
beginning of the first sentence of the effects clause from "Extracts
characters" to "Behaves as an unformatted input function (as described
in 27.6.1.3, paragraph 1).  After constructing a sentry object, extracts
characters"
</p>

<p>
[No change needed in paragraph 15.]
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 17.  Change the
beginning of the first sentence of the effects clause from "Extracts
characters" to "Behaves as an unformatted input function (as described
in 27.6.1.3, paragraph 1).  After constructing a sentry object, extracts
characters"
</p>

<p>
[No change needed in paragraph 23.]
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 24.  Change the
beginning of the first sentence of the effects clause from "Extracts
characters" to "Behaves as an unformatted input function (as described
in 27.6.1.3, paragraph 1).  After constructing a sentry object, extracts
characters"
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], before paragraph 27.  Add an
Effects clause: "Effects: Behaves as an unformatted input function (as
described in 27.6.1.3, paragraph 1).  After constructing a sentry
object, reads but does not extract the current input character."
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 28.  Change the
first sentence of the Effects clause from "If !good() calls" to
Behaves as an unformatted input function (as described in 27.6.1.3,
paragraph 1).  After constructing a sentry object, if !good() calls"
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 30.  Change the
first sentence of the Effects clause from "If !good() calls" to
"Behaves as an unformatted input function (as described in 27.6.1.3,
paragraph 1).  After constructing a sentry object, if !good() calls"
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 32.  Change the
first sentence of the Effects clause from "If !good() calls..." to
"Behaves as an unformatted input function (as described in 27.6.1.3,
paragraph 1).  After constructing a sentry object, if !good()
calls..."  Add a new sentence to the end of the Effects clause:
"[Note: this function extracts no characters, so the value returned
by the next call to gcount() is 0.]"
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 34.  Change the
first sentence of the Effects clause from "If !good() calls" to
"Behaves as an unformatted input function (as described in 27.6.1.3,
paragraph 1).  After constructing a sentry object, if !good() calls".
Add a new sentence to the end of the Effects clause: "[Note: this
function extracts no characters, so the value returned by the next
call to gcount() is 0.]"
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 36.  Change the
first sentence of the Effects clause from "If !rdbuf() is" to "Behaves
as an unformatted input function (as described in 27.6.1.3, paragraph
1), except that it does not count the number of characters extracted
and does not affect the value returned by subsequent calls to
gcount().  After constructing a sentry object, if rdbuf() is"
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], before paragraph 37.  Add an
Effects clause: "Effects: Behaves as an unformatted input function (as
described in 27.6.1.3, paragraph 1), except that it does not count the
number of characters extracted and does not affect the value returned
by subsequent calls to gcount()."  Change the first sentence of
paragraph 37 from "if fail()" to "after constructing a sentry object,
if fail()".
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 38.  Change the
first sentence of the Effects clause from "If fail()" to "Behaves
as an unformatted input function (as described in 27.6.1.3, paragraph
1), except that it does not count the number of characters extracted
and does not affect the value returned by subsequent calls to
gcount().  After constructing a sentry object, if fail()
</p>

<p>
In 27.6.1.3, [lib.istream.unformatted], paragraph 40.  Change the
first sentence of the Effects clause from "If fail()" to "Behaves
as an unformatted input function (as described in 27.6.1.3, paragraph
1), except that it does not count the number of characters extracted
and does not affect the value returned by subsequent calls to
gcount().  After constructing a sentry object, if fail()
</p>

<p>
In 27.6.2.5.2 [lib.ostream.inserters.arithmetic], paragraph 1.  Change
the beginning of the third sentence from "The formatting conversion"
to "These extractors behave as formatted output functions (as
described in 27.6.2.5.1).  After the sentry object is constructed, the
conversion occurs".
</p>

<p>
In 27.6.2.5.3 [lib.ostream.inserters], before paragraph 1.  Add an
effects clause: "Effects: None. Does not behave as a formatted output
function (as described in 27.6.2.5.1).".
</p>

<p>
In 27.6.2.5.3 [lib.ostream.inserters], paragraph 2.  Change the
effects clause to "Effects: calls pf(*this).  This extractor does not
behave as a formatted output function (as described in 27.6.2.5.1).".
</p>

<p>
In 27.6.2.5.3 [lib.ostream.inserters], paragraph 4.  Change the
effects clause to "Effects: calls pf(*this).  This extractor does not
behave as a formatted output function (as described in 27.6.2.5.1).".
</p>

<p>
In 27.6.2.5.3 [lib.ostream.inserters], paragraph 6.  Change the first
sentence from "If sb" to "Behaves as a formatted output function (as
described in 27.6.2.5.1).  After the sentry object is constructed, if
sb".
</p>

<p>
In 27.6.2.6 [lib.ostream.unformatted], paragraph 2.  Change the first
sentence from "Inserts the character" to "Behaves as an unformatted
output function (as described in 27.6.2.6, paragraph 1).  After
constructing a sentry object, inserts the character".
</p>

<p>
In 27.6.2.6 [lib.ostream.unformatted], paragraph 5.  Change the first
sentence from "Obtains characters" to "Behaves as an unformatted
output function (as described in 27.6.2.6, paragraph 1).  After
constructing a sentry object, obtains characters".
</p>

<p>
In 27.6.2.6 [lib.ostream.unformatted], paragraph 7.  Add a new
sentence at the end of the paragraph: "Does not behave as an
unformatted output function (as described in 27.6.2.6, paragraph 1)."
</p>
<p><b>Rationale:</b></p>
<p>See J16/99-0043==WG21/N1219, Proposed Resolution to Library Issue 60,
by Judy Ward and Matt Austern.  This proposed resolution is section
VI of that paper.</p>
<hr>
<a name="61"><h3>61.&nbsp;Ambiguity in iostreams exception policy</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The introduction to the section on unformatted input (27.6.1.3)
says that every unformatted input function catches all exceptions that
were thrown during input, sets badbit, and then conditionally rethrows
the exception. That seems clear enough. Several of the specific
functions, however, such as get() and read(), are documented in some
circumstances as setting eofbit and/or failbit. (The standard notes,
correctly, that setting eofbit or failbit can sometimes result in an
exception being thrown.) The question: if one of these functions
throws an exception triggered by setting failbit, is this an exception
"thrown during input" and hence covered by 27.6.1.3, or does
27.6.1.3 only refer to a limited class of exceptions? Just to make
this concrete, suppose you have the following snippet. </p>

<pre>  
  char buffer[N];
  istream is;
  ...
  is.exceptions(istream::failbit); // Throw on failbit but not on badbit.
  is.read(buffer, N);</pre>

<p>Now suppose we reach EOF before we've read N characters. What
iostate bits can we expect to be set, and what exception (if any) will
be thrown? </p>
<p><b>Proposed resolution:</b></p>
<p>
In 27.6.1.3, paragraph 1, after the sentence that begins
"If an exception is thrown...", add the following
parenthetical comment: "(Exceptions thrown from 
<tt>basic_ios&lt;&gt;::clear()</tt> are not caught or rethrown.)"
</p>
<p><b>Rationale:</b></p>
<p>The LWG looked to two alternative wordings, and choose the proposed
resolution as better standardese.</p>
<hr>
<a name="62"><h3>62.&nbsp;<tt>Sync</tt>'s return value</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;6 Aug 1998</p>
<p>The Effects clause for sync() (27.6.1.3, paragraph 36) says that it
"calls rdbuf()-&gt;pubsync() and, if that function returns -1
... returns traits::eof()." </p>

<p>That looks suspicious, because traits::eof() is of type
traits::int_type while the return type of sync() is int. </p>
<p><b>Proposed resolution:</b></p>
<p>In 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>, paragraph 36, change "returns
<tt>traits::eof()</tt>" to "returns <tt>-1</tt>".
</p>
<hr>
<a name="63"><h3>63.&nbsp;Exception-handling policy for unformatted output</h3></a><p><b>Section:</b>&nbsp;27.6.2.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.unformatted"> [lib.ostream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;11 Aug 1998</p>
<p>Clause 27 details an exception-handling policy for formatted input,
unformatted input, and formatted output. It says nothing for
unformatted output (27.6.2.6). 27.6.2.6 should either include the same
kind of exception-handling policy as in the other three places, or
else it should have a footnote saying that the omission is
deliberate. </p>
<p><b>Proposed resolution:</b></p>
<p>
In 27.6.2.6, paragraph 1, replace the last sentence ("In any
case, the unformatted output function ends by destroying the sentry
object, then returning the value specified for the formatted output
function.") with the following text:
</p>
<blockquote>
If an exception is thrown during output, then <tt>ios::badbit</tt> is
turned on [Footnote: without causing an <tt>ios::failure</tt> to be
thrown.] in <tt>*this</tt>'s error state. If <tt>(exceptions() &amp;
badbit) != 0</tt> then the exception is rethrown.  In any case, the
unformatted output function ends by destroying the sentry object,
then, if no exception was thrown, returning the value specified for
the formatted output function.
</blockquote>
<p><b>Rationale:</b></p>
<p>
This exception-handling policy is consistent with that of formatted
input, unformatted input, and formatted output.
</p>
<hr>
<a name="64"><h3>64.&nbsp;Exception handling in <tt>basic_istream::operator&gt;&gt;(basic_streambuf*)</tt>
</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;11 Aug 1998 </p>
<p>27.6.1.2.3, paragraph 13, is ambiguous. It can be interpreted two
different ways, depending on whether the second sentence is read as an
elaboration of the first. </p>
<p><b>Proposed resolution:</b></p>
<p>Replace 27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>, paragraph 13, which begins
"If the function inserts no characters ..." with:</p>

<blockquote>
  <p>If the function inserts no characters, it calls
  <tt>setstate(failbit)</tt>, which may throw
  <tt>ios_base::failure</tt> (27.4.4.3). If it inserted no characters
  because it caught an exception thrown while extracting characters
  from <tt>sb</tt> and <tt>failbit</tt> is on in <tt>exceptions()</tt>
  (27.4.4.3), then the caught exception is rethrown. </p>
</blockquote>
<hr>
<a name="66"><h3>66.&nbsp;Strstreambuf::setbuf</h3></a><p><b>Section:</b>&nbsp;D.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;18 Aug 1998</p>
<p>D.7.1.3, paragraph 19, says that strstreambuf::setbuf
"Performs an operation that is defined separately for each class
derived from strstreambuf". This is obviously an incorrect
cut-and-paste from basic_streambuf. There are no classes derived from
strstreambuf. </p>
<p><b>Proposed resolution:</b></p>
<p>D.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstreambuf.virtuals"> [depr.strstreambuf.virtuals]</a>, paragraph 19, replace the setbuf effects
clause which currently says "Performs an operation that is
defined separately for each class derived from strstreambuf"
with:</p>

<blockquote>
  <p><b>Effects</b>: implementation defined, except that
  <tt>setbuf(0,0)</tt> has no effect.</p>
</blockquote>
<hr>
<a name="68"><h3>68.&nbsp;Extractors for char* should store null at end</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;14 Jul 1998</p>
<p>Extractors for char* (27.6.1.2.3) do not store a null character
after the extracted character sequence whereas the unformatted
functions like get() do. Why is this?</p>

<p>Comment from Jerry Schwarz: There is apparently an editing
glitch. You'll notice that the last item of the list of what stops
extraction doesn't make any sense. It was supposed to be the line that
said a null is stored.</p>
<p><b>Proposed resolution:</b></p>
<p>27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>, paragraph 7, change the last list
item from:</p>

<blockquote>
  A null byte (<tt>charT()</tt>) in the next position, which may be
  the first position if no characters were extracted.
</blockquote>

<p>to become a new paragraph which reads:</p>

<blockquote>
  Operator&gt;&gt; then stores a null byte (<tt>charT()</tt>) in the
  next position, which may be the first position if no characters were
  extracted.
</blockquote>
<hr>
<a name="69"><h3>69.&nbsp;Must elements of a vector be contiguous?</h3></a><p><b>Section:</b>&nbsp;23.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.adaptors"> [lib.container.adaptors]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;29 Jul 1998</p>
<p>The issue is this: Must the elements of a vector be in contiguous memory?</p>

<p>(Please note that this is entirely separate from the question of
whether a vector iterator is required to be a pointer; the answer to
that question is clearly "no," as it would rule out
debugging implementations)</p>
<p><b>Proposed resolution:</b></p>
<p>Add the following text to the end of 23.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.adaptors"> [lib.container.adaptors]</a>,
paragraph 1. </p>

<blockquote>
  <p>The elements of a vector are stored contiguously, meaning that if
  v is a <tt>vector&lt;T, Allocator&gt;</tt> where T is some type
  other than <tt>bool</tt>, then it obeys the identity <tt>&amp;v[n]
  == &amp;v[0] + n</tt> for all <tt>0 &lt;= n &lt; v.size()</tt>.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>The LWG feels that as a practical matter the answer is clearly
"yes".  There was considerable discussion as to the best way
to express the concept of "contiguous", which is not
directly defined in the standard.  Discussion included:</p>

<ul>
  <li>An operational definition similar to the above proposed resolution is 
    already used for valarray (<font color="red">26.3.2.3</font>).</li>
  <li>There is no need to explicitly consider a user-defined operator&amp; 
    because elements must be copyconstructible (23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> para 3) 
    and copyconstructible (20.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.copyconstructible"> [lib.copyconstructible]</a>) specifies
    requirements for operator&amp;.</li>
  <li>There is no issue of one-past-the-end because of language rules.</li>
</ul>
<hr>
<a name="70"><h3>70.&nbsp;Uncaught_exception() missing throw() specification</h3></a><p><b>Section:</b>&nbsp;18.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.support.exception"> [lib.support.exception]</a>, 18.7.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.uncaught"> [lib.uncaught]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;Unknown</p>
<p>In article 3E04@pratique.fr, Valentin Bonnard writes: </p>

<p>uncaught_exception() doesn't have a throw specification.</p>

<p>It is intentional ? Does it means that one should be prepared to
handle exceptions thrown from uncaught_exception() ?</p>

<p>uncaught_exception() is called in exception handling contexts where
exception safety is very important.</p>
<p><b>Proposed resolution:</b></p>
<p>In 15.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/except.html#except.uncaught"> [except.uncaught]</a>, paragraph 1, 18.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.support.exception"> [lib.support.exception]</a>, and 18.7.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.uncaught"> [lib.uncaught]</a>, add "throw()" to uncaught_exception().</p>
<hr>
<a name="71"><h3>71.&nbsp;Do_get_monthname synopsis missing argument</h3></a><p><b>Section:</b>&nbsp;22.2.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.time.get"> [lib.locale.time.get]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;13 Aug 1998</p>
<p>The locale facet member <tt>time_get&lt;&gt;::do_get_monthname</tt>
is described in 22.2.5.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.time.get.virtuals"> [lib.locale.time.get.virtuals]</a> with five arguments,
consistent with do_get_weekday and with its specified use by member
get_monthname. However, in the synopsis, it is specified instead with
four arguments. The missing argument is the "end" iterator
value.</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.time.get"> [lib.locale.time.get]</a>, add an "end" argument to
the declaration of member do_monthname as follows:</p>

<pre>  virtual iter_type do_get_monthname(iter_type s, iter_type end, ios_base&amp;,
                                     ios_base::iostate&amp; err, tm* t) const;</pre>
<hr>
<a name="74"><h3>74.&nbsp;Garbled text for <tt>codecvt::do_max_length</tt>
</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;8 Sep 1998</p>
<p>The text of <tt>codecvt::do_max_length</tt>'s "Returns"
clause (22.2.1.5.2, paragraph 11) is garbled. It has unbalanced
parentheses and a spurious <b>n</b>.</p>
<p><b>Proposed resolution:</b></p>
<p>Replace <font color="red">22.2.1.5.2</font> paragraph 11 with the
following:</p>

<blockquote>
  <b>Returns</b>: The maximum value that
  <tt>do_length(state, from, from_end, 1)</tt> can return for any
  valid range <tt>[from, from_end)</tt> and <tt>stateT</tt> value
  <tt>state</tt>. The specialization <tt>codecvt&lt;char, char,
  mbstate_t&gt;::do_max_length()</tt> returns 1.
</blockquote>
<hr>
<a name="75"><h3>75.&nbsp;Contradiction in <tt>codecvt::length</tt>'s argument types</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp; Matt
Austern&nbsp; <b>Date:</b>&nbsp; 18 Sep 1998</p>
<p>The class synopses for classes <tt>codecvt&lt;&gt;</tt> (22.2.1.5)
and <tt>codecvt_byname&lt;&gt;</tt> (22.2.1.6) say that the first
parameter of the member functions <tt>length</tt> and
<tt>do_length</tt> is of type <tt>const stateT&amp;</tt>. The member
function descriptions, however (22.2.1.5.1, paragraph 6; 22.2.1.5.2,
paragraph 9) say that the type is <tt>stateT&amp;</tt>.  Either the
synopsis or the summary must be changed. </p>

<p>If (as I believe) the member function descriptions are correct,
then we must also add text saying how <tt>do_length</tt> changes its
<tt>stateT</tt> argument. </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>, and also in <font color="red">22.2.1.6</font>,
change the <tt>stateT</tt> argument type on both member
<tt>length()</tt> and member <tt>do_length()</tt> from </p>

<blockquote>
  <p><tt>const stateT&amp;</tt></p>
</blockquote>

<p>to</p>

<blockquote>
  <p><tt>stateT&amp;</tt></p>
</blockquote>

<p>In <font color="red">22.2.1.5.2</font>, add to the definition for member
<tt>do_length</tt> a paragraph:</p>

<blockquote>
  <p>Effects: The effect on the <tt>state</tt> argument is ``as if''
  it called <tt>do_in(state, from, from_end, from, to, to+max,
  to)</tt> for <tt>to</tt> pointing to a buffer of at least
  <tt>max</tt> elements.</p>
</blockquote>
<hr>
<a name="76"><h3>76.&nbsp;Can a <tt>codecvt</tt> facet always convert one internal character at a time?</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;25 Sep 1998</p>
<p>This issue concerns the requirements on classes derived from
<tt>codecvt</tt>, including user-defined classes. What are the
restrictions on the conversion from external characters
(e.g. <tt>char</tt>) to internal characters (e.g. <tt>wchar_t</tt>)?
Or, alternatively, what assumptions about <tt>codecvt</tt> facets can
the I/O library make? </p>

<p>The question is whether it's possible to convert from internal
characters to external characters one internal character at a time,
and whether, given a valid sequence of external characters, it's
possible to pick off internal characters one at a time. Or, to put it
differently: given a sequence of external characters and the
corresponding sequence of internal characters, does a position in the
internal sequence correspond to some position in the external
sequence? </p>

<p>To make this concrete, suppose that <tt>[first, last)</tt> is a
sequence of <i>M</i> external characters and that <tt>[ifirst,
ilast)</tt> is the corresponding sequence of <i>N</i> internal
characters, where <i>N &gt; 1</i>. That is, <tt>my_encoding.in()</tt>,
applied to <tt>[first, last)</tt>, yields <tt>[ifirst,
ilast)</tt>. Now the question: does there necessarily exist a
subsequence of external characters, <tt>[first, last_1)</tt>, such
that the corresponding sequence of internal characters is the single
character <tt>*ifirst</tt>?
</p>

<p>(What a "no" answer would mean is that
<tt>my_encoding</tt> translates sequences only as blocks. There's a
sequence of <i>M</i> external characters that maps to a sequence of
<i>N</i> internal characters, but that external sequence has no
subsequence that maps to <i>N-1</i> internal characters.) </p>

<p>Some of the wording in the standard, such as the description of
<tt>codecvt::do_max_length</tt> (<font color="red">22.2.1.5.2</font>,
paragraph 11) and <tt>basic_filebuf::underflow</tt> (27.8.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a>, paragraph 3) suggests that it must always be
possible to pick off internal characters one at a time from a sequence
of external characters. However, this is never explicitly stated one
way or the other. </p>

<p>This issue seems (and is) quite technical, but it is important if
we expect users to provide their own encoding facets. This is an area
where the standard library calls user-supplied code, so a well-defined
set of requirements for the user-supplied code is crucial. Users must
be aware of the assumptions that the library makes. This issue affects
positioning operations on <tt>basic_filebuf</tt>, unbuffered input,
and several of <tt>codecvt</tt>'s member functions. </p>
<p><b>Proposed resolution:</b></p>
<p>Add the following text as a new paragraph, following <font color="red">22.2.1.5.2</font> paragraph 2:</p>

<blockquote>
<p>A <tt>codecvt</tt> facet that is used by <tt>basic_filebuf</tt>
(27.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.file.streams"> [lib.file.streams]</a>) must have the property that if</p>
<pre>    do_out(state, from, from_end, from_next, to, to_lim, to_next)
</pre>
would return <tt>ok</tt>, where <tt>from != from_end</tt>, then 
<pre>    do_out(state, from, from + 1, from_next, to, to_end, to_next)
</pre>
must also return <tt>ok</tt>, and that if
<pre>    do_in(state, from, from_end, from_next, to, to_lim, to_next)
</pre>
would return <tt>ok</tt>, where <tt>to != to_lim</tt>, then
<pre>    do_in(state, from, from_end, from_next, to, to + 1, to_next)
</pre>
<p>must also return <tt>ok</tt>.  [<i>Footnote:</i> Informally, this
means that <tt>basic_filebuf</tt> assumes that the mapping from
internal to external characters is 1 to N: a <tt>codecvt</tt> that is
used by <tt>basic_filebuf</tt> must be able to translate characters
one internal character at a time.  <i>--End Footnote</i>]</p>
</blockquote>

<p><i>[Redmond: Minor change in proposed resolution.  Original
proposed resolution talked about "success", with a parenthetical
comment that success meant returning <tt>ok</tt>.  New wording
removes all talk about "success", and just talks about the
return value.]</i></p>

<p><b>Rationale:</b></p>

  <p>The proposed resoluion says that conversions can be performed one
  internal character at a time.  This rules out some encodings that
  would otherwise be legal.  The alternative answer would mean there
  would be some internal positions that do not correspond to any
  external file position.</p>
  <p>
  An example of an encoding that this rules out is one where the
  <tt>internT</tt> and <tt>externT</tt> are of the same type, and
  where the internal sequence <tt>c1 c2</tt> corresponds to the
  external sequence <tt>c2 c1</tt>.
  </p>
  <p>It was generally agreed that <tt>basic_filebuf</tt> relies
  on this property: it was designed under the assumption that
  the external-to-internal mapping is N-to-1, and it is not clear
  that <tt>basic_filebuf</tt> is implementable without that 
  restriction.
  </p>
  <p>
  The proposed resolution is expressed as a restriction on
  <tt>codecvt</tt> when used by <tt>basic_filebuf</tt>, rather
  than a blanket restriction on all <tt>codecvt</tt> facets,
  because <tt>basic_filebuf</tt> is the only other part of the 
  library that uses <tt>codecvt</tt>.  If a user wants to define
  a <tt>codecvt</tt> facet that implements a more general N-to-M
  mapping, there is no reason to prohibit it, so long as the user
  does not expect <tt>basic_filebuf</tt> to be able to use it.
  </p>
<hr>
<a name="78"><h3>78.&nbsp;Typo: event_call_back</h3></a><p><b>Section:</b>&nbsp;27.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
<p>typo: event_call_back should be event_callback &nbsp; </p>
<p><b>Proposed resolution:</b></p>
<p>In the 27.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a> synopsis change
"event_call_back" to "event_callback". </p>
<hr>
<a name="79"><h3>79.&nbsp;Inconsistent declaration of polar()</h3></a><p><b>Section:</b>&nbsp;26.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.synopsis"> [lib.complex.synopsis]</a>, 26.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.value.ops"> [lib.complex.value.ops]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
<p>In 26.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.synopsis"> [lib.complex.synopsis]</a> polar is declared as follows:</p>
<pre>   template&lt;class T&gt; complex&lt;T&gt; polar(const T&amp;, const T&amp;); </pre>

<p>In 26.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.value.ops"> [lib.complex.value.ops]</a> it is declared as follows:</p>
<pre>   template&lt;class T&gt; complex&lt;T&gt; polar(const T&amp; rho, const T&amp; theta = 0); </pre>

<p>Thus whether the second parameter is optional is not clear. </p>
<p><b>Proposed resolution:</b></p>
<p>In 26.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.synopsis"> [lib.complex.synopsis]</a> change:</p>
<pre>   template&lt;class T&gt; complex&lt;T&gt; polar(const T&amp;, const T&amp;);</pre>

<p>to:</p>
<pre>   template&lt;class T&gt; complex&lt;T&gt; polar(const T&amp; rho, const T&amp; theta = 0); </pre>
<hr>
<a name="80"><h3>80.&nbsp;Global Operators of complex declared twice</h3></a><p><b>Section:</b>&nbsp;26.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.cfenv.syn"> [lib.cfenv.syn]</a>, 26.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.fenv"> [lib.fenv]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
<p>Both 26.2.1 and 26.2.2 contain declarations of global operators for
class complex. This redundancy should be removed.</p>
<p><b>Proposed resolution:</b></p>
<p>Reduce redundancy according to the general style of the standard. </p>
<hr>
<a name="83"><h3>83.&nbsp;String::npos vs. string::max_size()</h3></a><p><b>Section:</b>&nbsp;21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
<p>Many string member functions throw if size is getting or exceeding
npos. However, I wonder why they don't throw if size is getting or
exceeding max_size() instead of npos.  May be npos is known at compile
time, while max_size() is known at runtime. However, what happens if
size exceeds max_size() but not npos, then? It seems the standard
lacks some clarifications here.</p>
<p><b>Proposed resolution:</b></p>
<p>After 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a> paragraph 4 ("The functions
described in this clause...") add a new paragraph:</p>

<blockquote>
  <p>For any string operation, if as a result of the operation, <tt> size()</tt> would exceed
  <tt> max_size()</tt> then
  the operation throws <tt>length_error</tt>.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>The LWG believes length_error is the correct exception to throw.</p>
<hr>
<a name="86"><h3>86.&nbsp;String constructors don't describe exceptions</h3></a><p><b>Section:</b>&nbsp;21.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.cons"> [lib.string.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
<p>The constructor from a range:</p>

<pre>template&lt;class InputIterator&gt; 
         basic_string(InputIterator begin, InputIterator end, 
                      const Allocator&amp; a = Allocator());</pre>

<p>lacks a throws clause. However, I would expect that it throws
according to the other constructors if the numbers of characters in
the range equals npos (or exceeds max_size(), see above). </p>
<p><b>Proposed resolution:</b></p>
<p>In 21.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.cons"> [lib.string.cons]</a>, Strike throws paragraphs for
constructors which say "Throws: length_error if n ==
npos."</p>
<p><b>Rationale:</b></p>
<p>Throws clauses for length_error if n == npos are no longer needed
because they are subsumed by the general wording added by the
resolution for issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#83">83</a>.</p>
<hr>
<a name="90"><h3>90.&nbsp;Incorrect description of operator &gt;&gt; for strings</h3></a><p><b>Section:</b>&nbsp;21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
<p>The effect of operator &gt;&gt; for strings contain the following item:</p>

<p>&nbsp;&nbsp;&nbsp; <tt>isspace(c,getloc())</tt> is true for the next available input
character c.</p>

<p>Here <tt>getloc()</tt> has to be replaced by <tt>is.getloc()</tt>. </p>
<p><b>Proposed resolution:</b></p>
<p>In 21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a> paragraph 1 Effects clause replace:</p>

<blockquote>
  <p><tt>isspace(c,getloc())</tt> is true for the next available input character c.</p>
</blockquote>

<p>with:</p>

<blockquote>
  <p><tt>isspace(c,is.getloc())</tt> is true for the next available input character c.</p>
</blockquote>
<hr>
<a name="91"><h3>91.&nbsp;Description of operator&gt;&gt; and getline() for string&lt;&gt; might cause endless loop</h3></a><p><b>Section:</b>&nbsp;21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
<p>Operator &gt;&gt; and getline() for strings read until eof()
in the input stream is true. However, this might never happen, if the
stream can't read anymore without reaching EOF. So shouldn't it be
changed into that it reads until !good() ? </p>
<p><b>Proposed resolution:</b></p>
<p>In 21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>, paragraph 1, replace:</p>
<blockquote>
Effects: Begins by constructing a sentry object k as if k were
constructed by typename basic_istream&lt;charT,traits&gt;::sentry k( is). If
bool( k) is true, it calls str.erase() and then extracts characters
from is and appends them to str as if by calling str.append(1, c). If
is.width() is greater than zero, the maximum number n of characters
appended is is.width(); otherwise n is str.max_size(). Characters are
extracted and appended until any of the following occurs:
</blockquote>
<p>with:</p>
<blockquote>
Effects: Behaves as a formatted input function (27.6.1.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.reqmts"> [lib.istream.formatted.reqmts]</a>).  After constructing a sentry object, if the
sentry converts to true, calls str.erase() and then extracts
characters from is and appends them to str as if by calling
str.append(1,c). If is.width() is greater than zero, the maximum
number n of characters appended is is.width(); otherwise n is
str.max_size(). Characters are extracted and appended until any of the
following occurs:
</blockquote>

<p>In 21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>, paragraph 6, replace</p>
<blockquote>
Effects: Begins by constructing a sentry object k as if by typename
basic_istream&lt;charT,traits&gt;::sentry k( is, true). If bool( k) is true,
it calls str.erase() and then extracts characters from is and appends
them to str as if by calling str.append(1, c) until any of the
following occurs:
</blockquote>
<p>with:</p>
<blockquote>
Effects: Behaves as an unformatted input function (27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>), except that it does not affect the value returned
by subsequent calls to basic_istream&lt;&gt;::gcount().  After
constructing a sentry object, if the sentry converts to true, calls
str.erase() and then extracts characters from is and appends them to
str as if by calling str.append(1,c) until any of the following
occurs:
</blockquote>

<p><i>[Redmond: Made changes in proposed resolution.  <tt>operator&gt;&gt;</tt>
should be a formatted input function, not an unformatted input function.
<tt>getline</tt> should not be required to set <tt>gcount</tt>, since
there is no mechanism for <tt>gcount</tt> to be set except by one of
<tt>basic_istream</tt>'s member functions.]</i></p>

<p><i>[Curaçao: Nico agrees with proposed resolution.]</i></p>

<p><b>Rationale:</b></p>
<p>The real issue here is whether or not these string input functions
get their characters from a streambuf, rather than by calling an
istream's member functions, a streambuf signals failure either by
returning eof or by throwing an exception; there are no other
possibilities.  The proposed resolution makes it clear that these two
functions do get characters from a streambuf.</p>
<hr>
<a name="92"><h3>92.&nbsp;Incomplete Algorithm Requirements</h3></a><p><b>Section:</b>&nbsp;25 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.algorithms"> [lib.algorithms]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;29 Sep 1998</p>
<p>The standard does not state, how often a function object is copied,
called, or the order of calls inside an algorithm. This may lead to
surprising/buggy behavior. Consider the following example: </p>

<pre>class Nth {    // function object that returns true for the nth element 
  private: 
    int nth;     // element to return true for 
    int count;   // element counter 
  public: 
    Nth (int n) : nth(n), count(0) { 
    } 
    bool operator() (int) { 
        return ++count == nth; 
    } 
}; 
.... 
// remove third element 
    list&lt;int&gt;::iterator pos; 
    pos = remove_if(coll.begin(),coll.end(),  // range 
                    Nth(3)),                  // remove criterion 
    coll.erase(pos,coll.end()); </pre>

<p>This call, in fact removes the 3rd <b>AND the 6th</b> element. This
happens because the usual implementation of the algorithm copies the
function object internally: </p>

<pre>template &lt;class ForwIter, class Predicate&gt; 
ForwIter std::remove_if(ForwIter beg, ForwIter end, Predicate op) 
{ 
    beg = find_if(beg, end, op); 
    if (beg == end) { 
        return beg; 
    } 
    else { 
        ForwIter next = beg; 
        return remove_copy_if(++next, end, beg, op); 
    } 
} </pre>

<p>The algorithm uses find_if() to find the first element that should
be removed. However, it then uses a copy of the passed function object
to process the resulting elements (if any). Here, Nth is used again
and removes also the sixth element. This behavior compromises the
advantage of function objects being able to have a state. Without any
cost it could be avoided (just implement it directly instead of
calling find_if()). </p>
<p><b>Proposed resolution:</b></p>

<p>Add a new paragraph following 25 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.algorithms"> [lib.algorithms]</a> paragraph 8:</p>
<blockquote>
[Note: Unless otherwise specified, algorithms that take function
objects as arguments are permitted to copy those function objects
freely.  Programmers for whom object identity is important should
consider using a wrapper class that points to a noncopied
implementation object, or some equivalent solution.]
</blockquote>

<p><i>[Dublin: Pete Becker felt that this may not be a defect,
but rather something that programmers need to be educated about.
There was discussion of adding wording to the effect that the number
and order of calls to function objects, including predicates, not
affect the behavior of the function object.]</i></p>

<p><i>[Pre-Kona: Nico comments: It seems the problem is that we don't
have a clear statement of "predicate" in the
standard. People including me seemed to think "a function
returning a Boolean value and being able to be called by an STL
algorithm or be used as sorting criterion or ... is a
predicate". But a predicate has more requirements: It should
never change its behavior due to a call or being copied. IMHO we have
to state this in the standard. If you like, see section 8.1.4 of my
library book for a detailed discussion.]</i></p>

<p><i>[Kona: Nico will provide wording to the effect that "unless
otherwise specified, the number of copies of and calls to function
objects by algorithms is unspecified".&nbsp; Consider placing in
25 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.algorithms"> [lib.algorithms]</a> after paragraph 9.]</i></p>

<p><i>[Santa Cruz: The standard doesn't currently guarantee that
  functions object won't be copied, and what isn't forbidden is
  allowed.  It is believed (especially since implementations that were
  written in concert with the standard do make copies of function
  objects) that this was intentional.  Thus, no normative change is
  needed.  What we should put in is a non-normative note suggesting to
  programmers that if they want to guarantee the lack of copying they
  should use something like the <tt>ref</tt> wrapper.]</i></p>

<p><i>[Oxford: Matt provided wording.]</i></p>


<hr>
<a name="98"><h3>98.&nbsp;Input iterator requirements are badly written</h3></a><p><b>Section:</b>&nbsp;24.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.input.iterators"> [lib.input.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
<p>Table 72 in 24.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.input.iterators"> [lib.input.iterators]</a> specifies semantics for
<tt>*r++</tt> of:</p>

<p>&nbsp;&nbsp; <tt>{ T tmp = *r; ++r; return tmp; }</tt></p>

<p>There are two problems with this.  First, the return type is
specified to be "T", as opposed to something like "convertible to T".
This is too specific: we want to allow *r++ to return an lvalue.</p>

<p>Second, writing the semantics in terms of code misleadingly
suggests that the effects *r++ should precisely replicate the behavior
of this code, including side effects.  (Does this mean that *r++
should invoke the copy constructor exactly as many times as the sample
code above would?) See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#334">334</a> for a similar
problem.</p>

<p><b>Proposed resolution:</b></p>
In Table 72 in 24.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.input.iterators"> [lib.input.iterators]</a>, change the return type
for <tt>*r++</tt> from <tt>T</tt> to "convertible to T".
<p><b>Rationale:</b></p>
<p>This issue has two parts: the return type, and the number of times
  the copy constructor is invoked.</p>

<p>The LWG believes the the first part is a real issue.  It's
  inappropriate for the return type to be specified so much more
  precisely for *r++ than it is for *r.  In particular, if r is of
  (say) type <tt>int*</tt>, then *r++ isn't <tt>int</tt>,
  but <tt>int&amp;</tt>.</p>

<p>The LWG does not believe that the number of times the copy
  constructor is invoked is a real issue.  This can vary in any case,
  because of language rules on copy constructor elision.  That's too
  much to read into these semantics clauses.</p>

<p>Additionally, as Dave Abrahams pointed out (c++std-lib-13703): since 
   we're told (24.1/3) that forward iterators satisfy all the requirements
   of input iterators, we can't impose any requirements in the Input
   Iterator requirements table that forward iterators don't satisfy.</p>
<hr>
<a name="103"><h3>103.&nbsp;set::iterator is required to be modifiable, but this allows modification of keys</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
<p>Set::iterator is described as implementation-defined with a
reference to the container requirement; the container requirement says
that const_iterator is an iterator pointing to const T and iterator an
iterator pointing to T.</p>

<p>23.1.2 paragraph 2 implies that the keys should not be modified to
break the ordering of elements. But that is not clearly
specified. Especially considering that the current standard requires
that iterator for associative containers be different from
const_iterator. Set, for example, has the following: </p>

<p><tt>typedef implementation defined iterator;<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; // See _lib.container.requirements_</tt></p>

<p>23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> actually requires that iterator type pointing
to T (table 65). Disallowing user modification of keys by changing the
standard to require an iterator for associative container to be the
same as const_iterator would be overkill since that will unnecessarily
significantly restrict the usage of associative container. A class to
be used as elements of set, for example, can no longer be modified
easily without either redesigning the class (using mutable on fields
that have nothing to do with ordering), or using const_cast, which
defeats requiring iterator to be const_iterator. The proposed solution
goes in line with trusting user knows what he is doing. </p>

<p><b>Other Options Evaluated:</b> </p>

<p>Option A.&nbsp;&nbsp; In 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>, paragraph 2, after
first sentence, and before "In addition,...", add one line:
</p>

<blockquote>
  <p>Modification of keys shall not change their strict weak ordering. </p>
</blockquote>

<p>Option B.&nbsp;Add three new sentences to 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>:</p>

<blockquote>
  <p>At the end of paragraph 5: "Keys in an associative container
  are immutable." At the end of paragraph 6: "For
  associative containers where the value type is the same as the key
  type, both <tt>iterator</tt> and <tt>const_iterator</tt> are
  constant iterators. It is unspecified whether or not
  <tt>iterator</tt> and <tt>const_iterator</tt> are the same
  type."</p>
</blockquote>

<p>Option C.&nbsp;To 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>, paragraph 3, which
currently reads:</p>

<blockquote>
  <p>The phrase ``equivalence of keys'' means the equivalence relation imposed by the
  comparison and not the operator== on keys. That is, two keys k1 and k2 in the same
  container are considered to be equivalent if for the comparison object comp, comp(k1, k2)
  == false &amp;&amp; comp(k2, k1) == false.</p>
</blockquote>

<p>&nbsp; add the following:</p>

<blockquote>
  <p>For any two keys k1 and k2 in the same container, comp(k1, k2) shall return the same
  value whenever it is evaluated. [Note: If k2 is removed from the container and later
  reinserted, comp(k1, k2) must still return a consistent value but this value may be
  different than it was the first time k1 and k2 were in the same container. This is
  intended to allow usage like a string key that contains a filename, where comp compares
  file contents; if k2 is removed, the file is changed, and the same k2 (filename) is
  reinserted, comp(k1, k2) must again return a consistent value but this value may be
  different than it was the previous time k2 was in the container.]</p>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Add the following to 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> at
the indicated location:</p>

<blockquote>
  <p>At the end of paragraph 3: "For any two keys k1 and k2 in the same container,
  calling comp(k1, k2) shall always return the same
  value."</p>
  <p>At the end of paragraph 5: "Keys in an associative container are immutable."</p>
  <p>At the end of paragraph 6: "For associative containers where the value type is the
  same as the key type, both <tt>iterator</tt> and <tt>const_iterator</tt> are constant
  iterators. It is unspecified whether or not <tt>iterator</tt> and <tt>const_iterator</tt>
  are the same type."</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>Several arguments were advanced for and against allowing set elements to be
mutable as long as the ordering was not effected. The argument which swayed the
LWG was one of safety; if elements were mutable, there would be no compile-time
way to detect of a simple user oversight which caused ordering to be
modified.  There was a report that this had actually happened in practice,
and had been painful to diagnose.  If users need to modify elements,
it is possible to use mutable members or const_cast.</p>

<p>Simply requiring that keys be immutable is not sufficient, because the comparison
object may indirectly (via pointers) operate on values outside of the keys.</p>

<p>
The types <tt>iterator</tt> and <tt>const_iterator</tt> are permitted
to be different types to allow for potential future work in which some
member functions might be overloaded between the two types.  No such
member functions exist now, and the LWG believes that user functionality
will not be impaired by permitting the two types to be the same.  A
function that operates on both iterator types can be defined for 
<tt>const_iterator</tt> alone, and can rely on the automatic
conversion from <tt>iterator</tt> to <tt>const_iterator</tt>.
</p>

<p><i>[Tokyo: The LWG crafted the proposed resolution and rationale.]</i></p>
<hr>
<a name="106"><h3>106.&nbsp;Numeric library private members are implementation defined</h3></a><p><b>Section:</b>&nbsp;26.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.member.ops"> [lib.complex.member.ops]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
<p>This is the only place in the whole standard where the implementation has to document
something private.</p>
<p><b>Proposed resolution:</b></p>
<p>
Remove the comment which says "// remainder implementation defined" from:
</p>

<ul>
  <li>26.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.member.ops"> [lib.complex.member.ops]</a>
</li>
  <li>26.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.value.ops"> [lib.complex.value.ops]</a>
</li>
  <li>26.3.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.transcendentals"> [lib.complex.transcendentals]</a>
</li>
  <li>26.3.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.cmplx.over"> [lib.cmplx.over]</a>
</li>
</ul>
<hr>
<a name="108"><h3>108.&nbsp;Lifetime of exception::what() return unspecified</h3></a><p><b>Section:</b>&nbsp;18.6.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.type.info"> [lib.type.info]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;AFNOR&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>
<p>In 18.6.1, paragraphs 8-9, the lifetime of the return value of
exception::what() is left unspecified. This issue has implications
with exception safety of exception handling: some exceptions should
not throw bad_alloc.</p>
<p><b>Proposed resolution:</b></p>
<p>Add to 18.6.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.type.info"> [lib.type.info]</a> paragraph 9 (exception::what notes
clause) the sentence:</p>

<blockquote>
  <p>The return value remains valid until the exception object from which it is obtained is
  destroyed or a non-const member function of the exception object is called.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>If an exception object has non-const members, they may be used
to set internal state that should affect the contents of the string
returned by <tt>what()</tt>.
</p>
<hr>
<a name="109"><h3>109.&nbsp;Missing binders for non-const sequence elements</h3></a><p><b>Section:</b>&nbsp;20.5.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.arithmetic.operations"> [lib.arithmetic.operations]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Bjarne Stroustrup&nbsp; <b>Date:</b>&nbsp;7 Oct 1998</p>

<p>There are no versions of binders that apply to non-const elements
of a sequence. This makes examples like for_each() using bind2nd() on
page 521 of "The C++ Programming Language (3rd)"
non-conforming. Suitable versions of the binders need to be added.</p>

<p>Further discussion from Nico:</p>

<p>What is probably meant here is shown in the following example:</p>

<pre>class Elem { 
  public: 
    void print (int i) const { } 
    void modify (int i) { } 
}; </pre>
<pre>int main() 
{ 
    vector&lt;Elem&gt; coll(2); 
    for_each (coll.begin(), coll.end(), bind2nd(mem_fun_ref(&amp;Elem::print),42));    // OK 
    for_each (coll.begin(), coll.end(), bind2nd(mem_fun_ref(&amp;Elem::modify),42));   // ERROR 
}</pre>

<p>The error results from the fact that bind2nd() passes its first
argument (the argument of the sequence) as constant reference. See the
following typical implementation:</p>

<blockquote>
  <pre>template &lt;class Operation&gt; 
class binder2nd 
  : public unary_function&lt;typename Operation::first_argument_type, 
                          typename Operation::result_type&gt; { 
protected: 
  Operation op; 
  typename Operation::second_argument_type value; 
public: 
  binder2nd(const Operation&amp; o, 
            const typename Operation::second_argument_type&amp; v) 
      : op(o), value(v) {} </pre>
  <pre> typename Operation::result_type 
  operator()(const typename Operation::first_argument_type&amp; x) const { 
    return op(x, value); 
  } 
};</pre>
</blockquote>

<p>The solution is to overload operator () of bind2nd for non-constant arguments:</p>

<blockquote>
  <pre>template &lt;class Operation&gt; 
class binder2nd 
  : public unary_function&lt;typename Operation::first_argument_type, 
                          typename Operation::result_type&gt; { 
protected: 
  Operation op; 
  typename Operation::second_argument_type value; 
public: 
  binder2nd(const Operation&amp; o, 
            const typename Operation::second_argument_type&amp; v) 
      : op(o), value(v) {} </pre>
  <pre> typename Operation::result_type 
  operator()(const typename Operation::first_argument_type&amp; x) const { 
    return op(x, value); 
  } 
  typename Operation::result_type 
  operator()(typename Operation::first_argument_type&amp; x) const { 
    return op(x, value); 
  } 
};</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>

<p><b>Howard believes there is a flaw</b> in this resolution.
See c++std-lib-9127.  We may need to reopen this issue.</p>

<p>In <font color="red">20.5.6.1</font> in the declaration of binder1st after:</p>
<blockquote>
  <p><tt>typename Operation::result_type<br>
  &nbsp;operator()(const typename Operation::second_argument_type&amp; x) const;</tt></p>
</blockquote>
<p>insert:</p>
<blockquote>
  <p><tt>typename Operation::result_type<br>
  &nbsp;operator()(typename Operation::second_argument_type&amp; x) const;</tt></p>
</blockquote>
<p>In <font color="red">20.5.6.3</font> in the declaration of binder2nd after:</p>
<blockquote>
  <p><tt>typename Operation::result_type<br>
  &nbsp;operator()(const typename Operation::first_argument_type&amp; x) const;</tt></p>
</blockquote>
<p>insert:</p>
<blockquote>
  <p><tt>typename Operation::result_type<br>
  &nbsp;operator()(typename Operation::first_argument_type&amp; x) const;</tt></p>
</blockquote>

<p><i>[Kona: The LWG discussed this at some length.It was agreed that
this is a mistake in the design, but there was no consensus on whether
it was a defect in the Standard.  Straw vote: NAD - 5.  Accept
proposed resolution - 3.  Leave open - 6.]</i></p>

<p><i>[Copenhagen: It was generally agreed that this was a defect.
Strap poll: NAD - 0.  Accept proposed resolution - 10. 
Leave open - 1.]</i></p>

<hr>
<a name="110"><h3>110.&nbsp;istreambuf_iterator::equal not const</h3></a><p><b>Section:</b>&nbsp;24.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator"> [lib.istreambuf.iterator]</a>, 24.5.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::equal"> [lib.istreambuf.iterator::equal]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;15 Oct 1998</p>
<p>Member istreambuf_iterator&lt;&gt;::equal is not declared
"const", yet 24.5.3.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::op=="> [lib.istreambuf.iterator::op==]</a> says that operator==,
which is const, calls it. This is contradictory. </p>
<p><b>Proposed resolution:</b></p>
<p>In 24.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator"> [lib.istreambuf.iterator]</a> and also in 24.5.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator::equal"> [lib.istreambuf.iterator::equal]</a>,
replace:</p>

<blockquote>
  <pre>bool equal(istreambuf_iterator&amp; b);</pre>
</blockquote>

<p>with:</p>

<blockquote>
  <pre>bool equal(const istreambuf_iterator&amp; b) const;</pre>
</blockquote>
<hr>
<a name="112"><h3>112.&nbsp;Minor typo in <tt>ostreambuf_iterator</tt> constructor</h3></a><p><b>Section:</b>&nbsp;24.5.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.ostreambuf.iter.cons"> [lib.ostreambuf.iter.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;20 Oct 1998</p>
<p>The <b>requires</b> clause for <tt>ostreambuf_iterator</tt>'s
constructor from an <tt>ostream_type</tt> (24.5.4.1, paragraph 1)
reads "<i>s</i> is not null". However, <i>s</i> is a
reference, and references can't be null. </p>
<p><b>Proposed resolution:</b></p>
<p>In 24.5.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.ostreambuf.iter.cons"> [lib.ostreambuf.iter.cons]</a>:</p>

<p>Move the current paragraph 1, which reads "Requires: s is not
null.", from the first constructor to the second constructor.</p>

<p>Insert a new paragraph 1 Requires clause for the first constructor
reading:</p>

<blockquote>
  <p><b>Requires</b>: <tt>s.rdbuf()</tt> is not null.</p>
</blockquote>
<hr>
<a name="114"><h3>114.&nbsp;Placement forms example in error twice</h3></a><p><b>Section:</b>&nbsp;18.5.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.placement"> [lib.new.delete.placement]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;28 Oct 1998</p>
<p>Section 18.5.1.3 contains the following example: </p>

<pre>[Example: This can be useful for constructing an object at a known address:
        char place[sizeof(Something)];
        Something* p = new (place) Something();
 -end example]</pre>

<p>First code line: "place" need not have any special alignment, and the
following constructor could fail due to misaligned data.</p>

<p>Second code line: Aren't the parens on Something() incorrect?&nbsp; [Dublin: the LWG
believes the () are correct.]</p>

<p>Examples are not normative, but nevertheless should not show code that is invalid or
likely to fail.</p>
<p><b>Proposed resolution:</b></p>
<p>Replace the <u> first line of code</u> in the example in 
18.5.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.placement"> [lib.new.delete.placement]</a> with:
</p>

<blockquote>
  <pre>void* place = operator new(sizeof(Something));</pre>
</blockquote>
<hr>
<a name="115"><h3>115.&nbsp;Typo in strstream constructors</h3></a><p><b>Section:</b>&nbsp;D.7.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstream.cons"> [depr.strstream.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;2 Nov 1998</p>
<p>D.7.4.1 strstream constructors paragraph 2 says: </p>

<blockquote>
  <p>Effects: Constructs an object of class strstream, initializing the base class with
  iostream(&amp; sb) and initializing sb with one of the two constructors: </p>
  <p>- If mode&amp;app==0, then s shall designate the first element of an array of n
  elements. The constructor is strstreambuf(s, n, s). </p>
  <p>- If mode&amp;app==0, then s shall designate the first element of an array of n
  elements that contains an NTBS whose first element is designated by s. The constructor is
  strstreambuf(s, n, s+std::strlen(s)).</p>
</blockquote>

<p>Notice the second condition is the same as the first. I think the second condition
should be "If mode&amp;app==app", or "mode&amp;app!=0", meaning that
the append bit is set.</p>
<p><b>Proposed resolution:</b></p>
<p>In D.7.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.ostrstream.cons"> [depr.ostrstream.cons]</a> paragraph 2 and D.7.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.strstream.cons"> [depr.strstream.cons]</a>
paragraph 2, change the first condition to <tt>(mode&amp;app)==0</tt>
and the second condition to <tt>(mode&amp;app)!=0</tt>.</p>
<hr>
<a name="117"><h3>117.&nbsp;<tt>basic_ostream</tt> uses nonexistent <tt>num_put</tt> member functions</h3></a><p><b>Section:</b>&nbsp;27.6.2.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters.arithmetic"> [lib.ostream.inserters.arithmetic]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;20 Nov 1998</p>
<p>The <b>effects</b> clause for numeric inserters says that
insertion of a value <tt>x</tt>, whose type is either <tt>bool</tt>,
<tt>short</tt>, <tt>unsigned short</tt>, <tt>int</tt>, <tt>unsigned
int</tt>, <tt>long</tt>, <tt>unsigned long</tt>, <tt>float</tt>,
<tt>double</tt>, <tt>long double</tt>, or <tt>const void*</tt>, is
delegated to <tt>num_put</tt>, and that insertion is performed as if
through the following code fragment: </p>

<pre>bool failed = use_facet&lt;
   num_put&lt;charT,ostreambuf_iterator&lt;charT,traits&gt; &gt; 
   &gt;(getloc()).put(*this, *this, fill(), val). failed();</pre>

<p>This doesn't work, because <tt>num_put&lt;&gt;</tt>::put is only
overloaded for the types <tt>bool</tt>, <tt>long</tt>, <tt>unsigned
long</tt>, <tt>double</tt>, <tt>long double</tt>, and <tt>const
void*</tt>. That is, the code fragment in the standard is incorrect
(it is diagnosed as ambiguous at compile time) for the types
<tt>short</tt>, <tt>unsigned short</tt>, <tt>int</tt>, <tt>unsigned
int</tt>, and <tt>float</tt>. </p>

<p>We must either add new member functions to <tt>num_put</tt>, or
else change the description in <tt>ostream</tt> so that it only calls
functions that are actually there. I prefer the latter. </p>
<p><b>Proposed resolution:</b></p>
<p>Replace 27.6.2.5.2, paragraph 1 with the following: </p>

<blockquote>
<p>
The classes num_get&lt;&gt; and num_put&lt;&gt; handle locale­dependent numeric
formatting and parsing.  These inserter functions use the imbued
locale value to perform numeric formatting.  When val is of type bool,
long, unsigned long, double, long double, or const void*, the
formatting conversion occurs as if it performed the following code
fragment:
</p>

<pre>bool failed = use_facet&lt;
   num_put&lt;charT,ostreambuf_iterator&lt;charT,traits&gt; &gt;
   &gt;(getloc()).put(*this, *this, fill(), val). failed();
</pre>

<p>
When val is of type short the formatting conversion occurs as if it
performed the following code fragment:
</p>

<pre>ios_base::fmtflags baseflags = ios_base::flags() &amp; ios_base::basefield;
bool failed = use_facet&lt;
   num_put&lt;charT,ostreambuf_iterator&lt;charT,traits&gt; &gt;
   &gt;(getloc()).put(*this, *this, fill(),
      baseflags == ios_base::oct || baseflags == ios_base::hex
         ? static_cast&lt;long&gt;(static_cast&lt;unsigned short&gt;(val))
         : static_cast&lt;long&gt;(val)). failed();
</pre>

<p>
When val is of type int the formatting conversion occurs as if it performed
the following code fragment:
</p>

<pre>ios_base::fmtflags baseflags = ios_base::flags() &amp; ios_base::basefield;
bool failed = use_facet&lt;
   num_put&lt;charT,ostreambuf_iterator&lt;charT,traits&gt; &gt;
   &gt;(getloc()).put(*this, *this, fill(),
      baseflags == ios_base::oct || baseflags == ios_base::hex
         ? static_cast&lt;long&gt;(static_cast&lt;unsigned int&gt;(val))
         : static_cast&lt;long&gt;(val)). failed();
</pre>

<p>
When val is of type unsigned short or unsigned int the formatting conversion
occurs as if it performed the following code fragment:
</p>

<pre>bool failed = use_facet&lt;
   num_put&lt;charT,ostreambuf_iterator&lt;charT,traits&gt; &gt;
   &gt;(getloc()).put(*this, *this, fill(), static_cast&lt;unsigned long&gt;(val)).
failed();
</pre>

<p>
When val is of type float the formatting conversion occurs as if it
performed the following code fragment:
</p>

<pre>bool failed = use_facet&lt;
   num_put&lt;charT,ostreambuf_iterator&lt;charT,traits&gt; &gt;
   &gt;(getloc()).put(*this, *this, fill(), static_cast&lt;double&gt;(val)).
failed();
</pre>

</blockquote>

<p><i>[post-Toronto: This differs from the previous proposed
resolution; PJP provided the new wording.  The differences are in
signed short and int output.]</i></p>
<p><b>Rationale:</b></p>
<p>The original proposed resolution was to cast int and short to long,
unsigned int and unsigned short to unsigned long, and float to double,
thus ensuring that we don't try to use nonexistent num_put&lt;&gt;
member functions.  The current proposed resolution is more
complicated, but gives more expected results for hex and octal output
of signed short and signed int.  (On a system with 16-bit short, for
example, printing short(-1) in hex format should yield 0xffff.)</p>
<hr>
<a name="118"><h3>118.&nbsp;<tt>basic_istream</tt> uses nonexistent <tt>num_get</tt> member functions</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.arithmetic"> [lib.istream.formatted.arithmetic]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;20 Nov 1998</p>
<p>Formatted input is defined for the types <tt>short</tt>, <tt>unsigned short</tt>, <tt>int</tt>,
<tt>unsigned int</tt>, <tt>long</tt>, <tt>unsigned long</tt>, <tt>float</tt>, <tt>double</tt>,
<tt>long double</tt>, <tt>bool</tt>, and <tt>void*</tt>. According to section 27.6.1.2.2,
formatted input of a value <tt>x</tt> is done as if by the following code fragment: </p>

<pre>typedef num_get&lt; charT,istreambuf_iterator&lt;charT,traits&gt; &gt; numget; 
iostate err = 0; 
use_facet&lt; numget &gt;(loc).get(*this, 0, *this, err, val); 
setstate(err);</pre>

<p>According to section 22.2.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.members"> [lib.facet.num.get.members]</a>, however,
<tt>num_get&lt;&gt;::get()</tt> is only overloaded for the types
<tt>bool</tt>, <tt>long</tt>, <tt>unsigned short</tt>, <tt>unsigned
int</tt>, <tt>unsigned long</tt>, <tt>unsigned long</tt>,
<tt>float</tt>, <tt>double</tt>, <tt>long double</tt>, and
<tt>void*</tt>. Comparing the lists from the two sections, we find
that 27.6.1.2.2 is using a nonexistent function for types
<tt>short</tt> and <tt>int</tt>. </p>
<p><b>Proposed resolution:</b></p>
<p>In 27.6.1.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.arithmetic"> [lib.istream.formatted.arithmetic]</a> Arithmetic Extractors, remove the
two lines (1st and 3rd) which read:</p>
<blockquote>
  <pre>operator&gt;&gt;(short&amp; val);
...
operator&gt;&gt;(int&amp; val);</pre>
</blockquote>

<p>And add the following at the end of that section (27.6.1.2.2) :</p>

<blockquote>
  <pre>operator&gt;&gt;(short&amp; val);</pre>
  <p>The conversion occurs as if performed by the following code fragment (using
  the same notation as for the preceding code fragment):</p>
  <pre>  typedef num_get&lt; charT,istreambuf_iterator&lt;charT,traits&gt; &gt; numget;
  iostate err = 0;
  long lval;
  use_facet&lt; numget &gt;(loc).get(*this, 0, *this, err, lval);
        if (err == 0
                &amp;&amp; (lval &lt; numeric_limits&lt;short&gt;::min() || numeric_limits&lt;short&gt;::max() &lt; lval))
                err = ios_base::failbit;
  setstate(err);</pre>
  <pre>operator&gt;&gt;(int&amp; val);</pre>
  <p>The conversion occurs as if performed by the following code fragment (using
  the same notation as for the preceding code fragment):</p>
  <pre>  typedef num_get&lt; charT,istreambuf_iterator&lt;charT,traits&gt; &gt; numget;
  iostate err = 0;
  long lval;
  use_facet&lt; numget &gt;(loc).get(*this, 0, *this, err, lval);
        if (err == 0
                &amp;&amp; (lval &lt; numeric_limits&lt;int&gt;::min() || numeric_limits&lt;int&gt;::max() &lt; lval))
                err = ios_base::failbit;
  setstate(err);</pre>
</blockquote>

<p><i>[Post-Tokyo: PJP provided the above wording.]</i></p>
<hr>
<a name="119"><h3>119.&nbsp;Should virtual functions be allowed to strengthen the exception specification?</h3></a><p><b>Section:</b>&nbsp;17.4.4.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.exception.handling"> [lib.res.on.exception.handling]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;15 Dec 1998</p>
<p>Section 17.4.4.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.exception.handling"> [lib.res.on.exception.handling]</a> states: </p>

<p>"An implementation may strengthen the exception-specification
for a function by removing listed exceptions." </p>

<p>The problem is that if an implementation is allowed to do this for
virtual functions, then a library user cannot write a class that
portably derives from that class. </p>

<p>For example, this would not compile if ios_base::failure::~failure
had an empty exception specification: </p>

<pre>#include &lt;ios&gt;
#include &lt;string&gt;

class D : public std::ios_base::failure {
public:
        D(const std::string&amp;);
        ~D(); // error - exception specification must be compatible with 
              // overridden virtual function ios_base::failure::~failure()
};</pre>
<p><b>Proposed resolution:</b></p>
<p>Change Section 17.4.4.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.exception.handling"> [lib.res.on.exception.handling]</a> from:</p>

<p>&nbsp;&nbsp;&nbsp;&nbsp; "may strengthen the
exception-specification for a function"</p>

<p>to:</p>

<p>&nbsp;&nbsp;&nbsp;&nbsp; "may strengthen the
exception-specification for a non-virtual function". </p>
<hr>
<a name="120"><h3>120.&nbsp;Can an implementor add specializations?</h3></a><p><b>Section:</b>&nbsp;17.4.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.reserved.names"> [lib.reserved.names]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;15 Dec 1998</p>

<p>The original issue asked whether a library implementor could
specialize standard library templates for built-in types.  (This was
an issue because users are permitted to explicitly instantiate
standard library templates.)</p>

<p>Specializations are no longer a problem, because of the resolution
to core issue 259.  Under the proposed resolution, it will be legal
for a translation unit to contain both a specialization and an
explicit instantiation of the same template, provided that the
specialization comes first.  In such a case, the explicit
instantiation will be ignored.  Further discussion of library issue
120 assumes that the core 259 resolution will be adopted.</p>

<p>However, as noted in lib-7047, one piece of this issue still
remains: what happens if a standard library implementor explicitly
instantiates a standard library templates?  It's illegal for a program
to contain two different explicit instantiations of the same template
for the same type in two different translation units (ODR violation),
and the core working group doesn't believe it is practical to relax
that restriction.</p>

<p>The issue, then, is: are users allowed to explicitly instantiate
standard library templates for non-user defined types?  The status quo
answer is 'yes'.  Changing it to 'no' would give library implementors
more freedom.</p>

<p>This is an issue because, for performance reasons, library
implementors often need to explicitly instantiate standard library
templates.  (for example, std::basic_string&lt;char&gt;)  Does giving
users freedom to explicitly instantiate standard library templates for
non-user defined types make it impossible or painfully difficult for
library implementors to do this?</p>

<p>John Spicer suggests, in lib-8957, that library implementors have a
mechanism they can use for explicit instantiations that doesn't
prevent users from performing their own explicit instantiations: put
each explicit instantiation in its own object file.  (Different
solutions might be necessary for Unix DSOs or MS-Windows DLLs.)  On
some platforms, library implementors might not need to do anything
special: the "undefined behavior" that results from having two
different explicit instantiations might be harmless.</p>

<p><b>Proposed resolution:</b></p>
  <p>Append to 17.4.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.reserved.names"> [lib.reserved.names]</a> paragraph 1: </p>
  <blockquote>
    A program may explicitly instantiate any templates in the standard
    library only if the declaration depends on the name of a user-defined
    type of external linkage and the instantiation meets the standard library
    requirements for the original template.
  </blockquote>

<p><i>[Kona: changed the wording from "a user-defined name" to "the name of
  a user-defined type"]</i></p>

<p><b>Rationale:</b></p>
<p>The LWG considered another possible resolution:</p>
<blockquote>
  <p>In light of the resolution to core issue 259, no normative changes
  in the library clauses are necessary.  Add the following non-normative
  note to the end of 17.4.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.reserved.names"> [lib.reserved.names]</a> paragraph 1:</p>
  <blockquote>
    [<i>Note:</i> A program may explicitly instantiate standard library
    templates, even when an explicit instantiation does not depend on
    a user-defined name. <i>--end note</i>]
  </blockquote>
</blockquote>

<p>The LWG rejected this because it was believed that it would make
  it unnecessarily difficult for library implementors to write
  high-quality implementations.  A program may not include an
  explicit instantiation of the same template, for the same template
  arguments, in two different translation units.  If users are
  allowed to provide explicit instantiations of Standard Library
  templates for built-in types, then library implementors aren't,
  at least not without nonportable tricks.</p>

<p>The most serious problem is a class template that has writeable
  static member variables.  Unfortunately, such class templates are
  important and, in existing Standard Library implementations, are
  often explicitly specialized by library implementors: locale facets,
  which have a writeable static member variable <tt>id</tt>.  If a
  user's explicit instantiation collided with the implementations
  explicit instantiation, iostream initialization could cause locales
  to be constructed in an inconsistent state.</p>

<p>One proposed implementation technique was for Standard Library
  implementors to provide explicit instantiations in separate object
  files, so that they would not be picked up by the linker when the
  user also provides an explicit instantiation.  However, this
  technique only applies for Standard Library implementations that
  are packaged as static archives.  Most Standard Library
  implementations nowadays are packaged as dynamic libraries, so this
  technique would not apply.</p>

<p>The Committee is now considering standardization of dynamic
  linking.  If there are such changes in the future, it may be
  appropriate to revisit this issue later.</p>
<hr>
<a name="122"><h3>122.&nbsp;streambuf/wstreambuf description should not say they are specializations</h3></a><p><b>Section:</b>&nbsp;27.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf"> [lib.streambuf]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;15 Dec 1998</p>
<p>Section 27.5.2 describes the streambuf classes this way: </p>

<blockquote>

<p>The class streambuf is a specialization of the template class basic_streambuf
specialized for the type char. </p>

<p>The class wstreambuf is a specialization of the template class basic_streambuf
specialized for the type wchar_t. </p>

</blockquote>

<p>This implies that these classes must be template specializations, not typedefs. </p>

<p>It doesn't seem this was intended, since Section 27.5 has them declared as typedefs. </p>
<p><b>Proposed resolution:</b></p>
<p>Remove 27.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf"> [lib.streambuf]</a> paragraphs 2 and 3 (the above two
sentences). </p>
<p><b>Rationale:</b></p>
<p>The <tt>streambuf</tt>  synopsis already has a declaration for the
typedefs and that is sufficient. </p>
<hr>
<a name="123"><h3>123.&nbsp;Should valarray helper arrays fill functions be const?</h3></a><p><b>Section:</b>&nbsp;26.5.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.slice.arr.fill"> [lib.slice.arr.fill]</a>, 26.5.7.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.gslice.array.fill"> [lib.gslice.array.fill]</a>, 26.5.8.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.mask.array.fill"> [lib.mask.array.fill]</a>, 26.5.9.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.indirect.array.fill"> [lib.indirect.array.fill]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;15 Dec 1998 </p>
<p>One of the operator= in the valarray helper arrays is const and one
is not. For example, look at slice_array. This operator= in Section
26.5.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.slice.arr.assign"> [lib.slice.arr.assign]</a> is const: </p>

<p>&nbsp;&nbsp;&nbsp; <tt>void operator=(const valarray&lt;T&gt;&amp;) const;</tt> </p>

<p>but this one in Section 26.5.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.slice.arr.fill"> [lib.slice.arr.fill]</a> is not: </p>

<p>&nbsp;&nbsp;&nbsp; <tt>void operator=(const T&amp;); </tt></p>

<p>The description of the semantics for these two functions is similar. </p>
<p><b>Proposed resolution:</b></p>

<p>26.5.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.slice.array"> [lib.template.slice.array]</a> Template class slice_array</p>
<blockquote>

   <p>In the class template definition for slice_array, replace the member
   function declaration</p>
    <pre>      void operator=(const T&amp;);
    </pre>
   <p>with</p>
    <pre>      void operator=(const T&amp;) const;
    </pre>
</blockquote>

<p>26.5.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.slice.arr.fill"> [lib.slice.arr.fill]</a> slice_array fill function</p>
<blockquote>

   <p>Change the function declaration</p>
    <pre>      void operator=(const T&amp;);
    </pre>
   <p>to</p>
    <pre>      void operator=(const T&amp;) const;
    </pre>
</blockquote>

<p>26.5.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.gslice.array"> [lib.template.gslice.array]</a> Template class gslice_array</p>
<blockquote>

   <p>In the class template definition for gslice_array, replace the member
   function declaration</p>
    <pre>      void operator=(const T&amp;);
    </pre>
   <p>with</p>
    <pre>      void operator=(const T&amp;) const;
    </pre>
</blockquote>

<p>26.5.7.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.gslice.array.fill"> [lib.gslice.array.fill]</a> gslice_array fill function</p>
<blockquote>

   <p>Change the function declaration</p>
    <pre>      void operator=(const T&amp;);
    </pre>
   <p>to</p>
    <pre>      void operator=(const T&amp;) const;
    </pre>
</blockquote>

<p>26.5.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.mask.array"> [lib.template.mask.array]</a> Template class mask_array</p>
<blockquote>

   <p>In the class template definition for mask_array, replace the member
   function declaration</p>
    <pre>      void operator=(const T&amp;);
    </pre>
   <p>with</p>
    <pre>      void operator=(const T&amp;) const;
    </pre>
</blockquote>

<p>26.5.8.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.mask.array.fill"> [lib.mask.array.fill]</a> mask_array fill function</p>
<blockquote>

   <p>Change the function declaration</p>
    <pre>      void operator=(const T&amp;);
    </pre>
   <p>to</p>
    <pre>      void operator=(const T&amp;) const;
    </pre>
</blockquote>

<p>26.5.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.indirect.array"> [lib.template.indirect.array]</a> Template class indirect_array</p>
<blockquote>

   <p>In the class template definition for indirect_array, replace the member
   function declaration</p>
    <pre>      void operator=(const T&amp;);
    </pre>
   <p>with</p>
    <pre>      void operator=(const T&amp;) const;
    </pre>
</blockquote>

<p>26.5.9.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.indirect.array.fill"> [lib.indirect.array.fill]</a> indirect_array fill function</p>
<blockquote>

   <p>Change the function declaration</p>
    <pre>      void operator=(const T&amp;);
    </pre>
   <p>to</p>
    <pre>      void operator=(const T&amp;) const;
    </pre>
</blockquote>


<p><i>[Redmond: Robert provided wording.]</i></p>

<p><b>Rationale:</b></p>
<p>There's no good reason for one version of operator= being const and
another one not.  Because of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#253">253</a>, this now
matters: these functions are now callable in more circumstances.  In
many existing implementations, both versions are already const.</p>
<hr>
<a name="124"><h3>124.&nbsp;ctype_byname&lt;charT&gt;::do_scan_is &amp; do_scan_not return type should be const charT*</h3></a><p><b>Section:</b>&nbsp;22.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.byname"> [lib.locale.ctype.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;15 Dec 1998</p>
<p>In Section 22.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.byname"> [lib.locale.ctype.byname]</a>
ctype_byname&lt;charT&gt;::do_scan_is() and do_scan_not() are declared
to return a const char* not a const charT*. </p>
<p><b>Proposed resolution:</b></p>
<p>Change Section 22.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.byname"> [lib.locale.ctype.byname]</a> <tt>do_scan_is()</tt> and
<tt>do_scan_not()</tt> to return a <tt> const
charT*</tt>. </p>
<hr>
<a name="125"><h3>125.&nbsp;valarray&lt;T&gt;::operator!() return type is inconsistent</h3></a><p><b>Section:</b>&nbsp;26.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex"> [lib.complex]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;15 Dec 1998</p>
<p>In Section 26.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex"> [lib.complex]</a> valarray&lt;T&gt;::operator!() is
declared to return a valarray&lt;T&gt;, but in Section <font color="red">26.3.2.5</font> it is declared to return a valarray&lt;bool&gt;. The
latter appears to be correct. </p>
<p><b>Proposed resolution:</b></p>
<p>Change in Section 26.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex"> [lib.complex]</a> the declaration of
<tt>operator!()</tt> so that the return type is
<tt>valarray&lt;bool&gt;</tt>. </p>
<hr>
<a name="126"><h3>126.&nbsp;typos in Effects clause of ctype::do_narrow()</h3></a><p><b>Section:</b>&nbsp;22.2.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;15 Dec 1998</p>
<p>Typos in 22.2.1.1.2 need to be fixed.</p>
<p><b>Proposed resolution:</b></p>
<p>In Section 22.2.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a> change: </p>

<pre>   do_widen(do_narrow(c),0) == c</pre>

<p>to:</p>

<pre>   do_widen(do_narrow(c,0)) == c</pre>

<p>and change:</p>

<pre>   (is(M,c) || !ctc.is(M, do_narrow(c),dfault) )</pre>

<p>to:</p>

<pre>   (is(M,c) || !ctc.is(M, do_narrow(c,dfault)) )</pre>
<hr>
<a name="127"><h3>127.&nbsp;auto_ptr&lt;&gt; conversion issues</h3></a><p><b>Section:</b>&nbsp;20.4.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary"> [lib.meta.unary]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Greg Colvin&nbsp; <b>Date:</b>&nbsp;17 Feb 1999</p>
<p>There are two problems with the current <tt>auto_ptr</tt> wording
in the standard: </p>

<p>First, the <tt>auto_ptr_ref</tt> definition cannot be nested
because <tt>auto_ptr&lt;Derived&gt;::auto_ptr_ref</tt> is unrelated to
<tt>auto_ptr&lt;Base&gt;::auto_ptr_ref</tt>.  <i>Also submitted by
Nathan Myers, with the same proposed resolution.</i></p>

<p>Second, there is no <tt>auto_ptr</tt> assignment operator taking an
<tt>auto_ptr_ref</tt> argument. </p>

<p>I have discussed these problems with my proposal coauthor, Bill
Gibbons, and with some compiler and library implementors, and we
believe that these problems are not desired or desirable implications
of the standard. </p>

<p>25 Aug 1999: The proposed resolution now reflects changes suggested
by Dave Abrahams, with Greg Colvin's concurrence; 1) changed
"assignment operator" to "public assignment
operator", 2) changed effects to specify use of release(), 3)
made the conversion to auto_ptr_ref const. </p>

<p>2 Feb 2000: Lisa Lippincott comments: [The resolution of] this issue
states that the conversion from auto_ptr to auto_ptr_ref should
be const.  This is not acceptable, because it would allow
initialization and assignment from _any_ const auto_ptr!  It also
introduces an implementation difficulty in writing this conversion
function -- namely, somewhere along the line, a const_cast will be
necessary to remove that const so that release() may be called.  This
may result in undefined behavior [7.1.5.1/4]. The conversion
operator does not have to be const, because a non-const implicit
object parameter may be bound to an rvalue [13.3.3.1.4/3]
[13.3.1/5]. </p>

  <p>Tokyo: The LWG removed the following from the proposed resolution:</p>

  <p>In 20.4.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary"> [lib.meta.unary]</a>, paragraph 2, and 20.4.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary.prop"> [lib.meta.unary.prop]</a>, 
  paragraph 2, make the conversion to auto_ptr_ref const:</p>
  <blockquote>
    <pre>template&lt;class Y&gt; operator auto_ptr_ref&lt;Y&gt;() const throw();</pre>
  </blockquote>
<p><b>Proposed resolution:</b></p>
<p>In 20.4.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary"> [lib.meta.unary]</a>, paragraph 2, move
the <tt>auto_ptr_ref</tt> definition to namespace scope.</p>

<p>In 20.4.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary"> [lib.meta.unary]</a>, paragraph 2, add
a public assignment operator to the <tt>auto_ptr</tt> definition: </p>

<blockquote>
  <pre>auto_ptr&amp; operator=(auto_ptr_ref&lt;X&gt; r) throw();</pre>
</blockquote>

<p>Also add the assignment operator to 20.4.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.unary.prop"> [lib.meta.unary.prop]</a>: </p>

<blockquote>
  <pre>auto_ptr&amp; operator=(auto_ptr_ref&lt;X&gt; r) throw()</pre>

  <b>Effects:</b> Calls <tt>reset(p.release())</tt> for the <tt>auto_ptr
  p</tt> that <tt>r</tt> holds a reference to.<br>
  <b>Returns: </b><tt>*this</tt>.

</blockquote>
<hr>
<a name="129"><h3>129.&nbsp;Need error indication from seekp() and seekg()</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>, 27.6.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.seeks"> [lib.ostream.seeks]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;22 Feb 1999</p>
<p>Currently, the standard does not specify how seekg() and seekp()
indicate failure. They are not required to set failbit, and they can't
return an error indication because they must return *this, i.e. the
stream. Hence, it is undefined what happens if they fail. And they
<i>can</i> fail, for instance, when a file stream is disconnected from the
underlying file (is_open()==false) or when a wide character file
stream must perform a state-dependent code conversion, etc. </p>

<p>The stream functions seekg() and seekp() should set failbit in the
stream state in case of failure.</p>
<p><b>Proposed resolution:</b></p>
<p>Add to the Effects: clause of&nbsp; seekg() in 
27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> and to the Effects: clause of seekp() in
27.6.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.seeks"> [lib.ostream.seeks]</a>: </p>

<blockquote>
  <p>In case of failure, the function calls <tt>setstate(failbit)</tt> (which may throw <tt>ios_base::failure</tt>).
  </p>
</blockquote>
<p><b>Rationale:</b></p>
<p>Setting failbit is the usual error reporting mechanism for streams</p>
<hr>
<a name="130"><h3>130.&nbsp;Return type of container::erase(iterator) differs for associative containers</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>, 23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;2 Mar 1999</p>
<p>Table 67 (23.1.1) says that container::erase(iterator) returns an
iterator. Table 69 (23.1.2) says that in addition to this requirement,
associative containers also say that container::erase(iterator)
returns void.  That's not an addition; it's a change to the
requirements, which has the effect of making associative containers
fail to meet the requirements for containers.</p>
<p><b>Proposed resolution:</b></p>

<p>
In 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>, in Table 69 Associative container
requirements, change the return type of <tt>a.erase(q)</tt> from
<tt>void</tt> to <tt>iterator</tt>.  Change the
assertion/not/pre/post-condition from "erases the element pointed to
by <tt>q</tt>" to "erases the element pointed to by <tt>q</tt>.
Returns an iterator pointing to the element immediately following q
prior to the element being erased. If no such element exists, a.end()
is returned."
</p>

<p>
In 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>, in Table 69 Associative container
requirements, change the return type of <tt>a.erase(q1, q2)</tt>
from <tt>void</tt> to <tt>iterator</tt>.  Change the
assertion/not/pre/post-condition from "erases the elements in the
range <tt>[q1, q2)</tt>" to "erases the elements in the range <tt>[q1,
q2)</tt>.  Returns q2."
</p>

<p>
In 23.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map"> [lib.map]</a>, in the <tt>map</tt> class synopsis; and 
in 23.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.multimap"> [lib.multimap]</a>, in the <tt>multimap</tt> class synopsis; and
in 23.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.set"> [lib.set]</a>, in the <tt>set</tt> class synopsis; and
in 23.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.multiset"> [lib.multiset]</a>, in the <tt>multiset</tt> class synopsis:
change the signature of the first <tt>erase</tt> overload to
</p>
<pre>   iterator erase(iterator position);
</pre>
<p>and change the signature of the third <tt>erase</tt> overload to</p>
<pre>  iterator erase(iterator first, iterator last); 
</pre>


<p><i>[Pre-Kona: reopened at the request of Howard Hinnant]</i></p>

<p><i>[Post-Kona: the LWG agrees the return type should be
<tt>iterator</tt>, not <tt>void</tt>.  (Alex Stepanov agrees too.)
Matt provided wording.]</i></p>

<p><i>[
 Sydney: the proposed wording went in the right direction, but it
 wasn't good enough. We want to return an iterator from the range form
 of erase as well as the single-iterator form. Also, the wording is
 slightly different from the wording we have for sequences; there's no
 good reason for having a difference.  Matt provided new wording,
 which we will review at the next meeting.
]</i></p>

<hr>
<a name="132"><h3>132.&nbsp;list::resize description uses random access iterators</h3></a><p><b>Section:</b>&nbsp;23.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.capacity"> [lib.deque.capacity]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;6 Mar 1999</p>
<p>The description reads:</p>

<p>-1- Effects:</p>

<pre>         if (sz &gt; size())
           insert(end(), sz-size(), c);
         else if (sz &lt; size())
           erase(begin()+sz, end());
         else
           ;                           //  do nothing</pre>

<p>Obviously list::resize should not be specified in terms of random access iterators.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 23.2.2.2 paragraph 1 to:</p>

<p>Effects:</p>

<pre>         if (sz &gt; size())
           insert(end(), sz-size(), c);
         else if (sz &lt; size())
         {
           iterator i = begin();
           advance(i, sz);
           erase(i, end());
         }</pre>

<p><i>[Dublin: The LWG asked Howard to discuss exception safety offline
with David Abrahams. They had a discussion and believe there is
no issue of exception safety with the proposed resolution.]</i></p>
<hr>
<a name="133"><h3>133.&nbsp;map missing get_allocator()</h3></a><p><b>Section:</b>&nbsp;23.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map"> [lib.map]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;6 Mar 1999</p>
<p>The title says it all.</p>
<p><b>Proposed resolution:</b></p>
<p>Insert in 23.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map"> [lib.map]</a>, paragraph 2,
after operator= in the map declaration:</p>

<pre>    allocator_type get_allocator() const;</pre>
<hr>
<a name="134"><h3>134.&nbsp;vector constructors over specified</h3></a><p><b>Section:</b>&nbsp;23.2.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.queue"> [lib.queue]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;6 Mar 1999</p>
<p>The complexity description says: "It does at most 2N calls to the copy constructor
of T and logN reallocations if they are just input iterators ...".</p>

<p>This appears to be overly restrictive, dictating the precise memory/performance
tradeoff for the implementor.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 23.2.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.queue"> [lib.queue]</a>, paragraph 1 to:</p>

<p>-1- Complexity: The constructor template &lt;class
InputIterator&gt; vector(InputIterator first, InputIterator last)
makes only N calls to the copy constructor of T (where N is the
distance between first and last) and no reallocations if iterators
first and last are of forward, bidirectional, or random access
categories. It makes order N calls to the copy constructor of T and
order logN reallocations if they are just input iterators.
</p>
<p><b>Rationale:</b></p>
<p>"at most 2N calls" is correct only if the growth factor
is greater than or equal to 2.
</p>
<hr>
<a name="136"><h3>136.&nbsp;seekp, seekg setting wrong streams?</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;6 Mar 1999</p>
<p>I may be misunderstanding the intent, but should not seekg set only
the input stream and seekp set only the output stream? The description
seems to say that each should set both input and output streams. If
that's really the intent, I withdraw this proposal.</p>
<p><b>Proposed resolution:</b></p>
<p>In section 27.6.1.3 change:</p>

<pre>basic_istream&lt;charT,traits&gt;&amp; seekg(pos_type pos);
Effects: If fail() != true, executes rdbuf()-&gt;pubseekpos(pos). </pre>

<p>To:</p>

<pre>basic_istream&lt;charT,traits&gt;&amp; seekg(pos_type pos);
Effects: If fail() != true, executes rdbuf()-&gt;pubseekpos(pos, ios_base::in). </pre>

<p>In section 27.6.1.3 change:</p>

<pre>basic_istream&lt;charT,traits&gt;&amp; seekg(off_type&amp; off, ios_base::seekdir dir);
Effects: If fail() != true, executes rdbuf()-&gt;pubseekoff(off, dir). </pre>

<p>To:</p>

<pre>basic_istream&lt;charT,traits&gt;&amp; seekg(off_type&amp; off, ios_base::seekdir dir);
Effects: If fail() != true, executes rdbuf()-&gt;pubseekoff(off, dir, ios_base::in). </pre>

<p>In section 27.6.2.4, paragraph 2 change:</p>

<pre>-2- Effects: If fail() != true, executes rdbuf()-&gt;pubseekpos(pos). </pre>

<p>To:</p>

<pre>-2- Effects: If fail() != true, executes rdbuf()-&gt;pubseekpos(pos, ios_base::out). </pre>

<p>In section 27.6.2.4, paragraph 4 change:</p>

<pre>-4- Effects: If fail() != true, executes rdbuf()-&gt;pubseekoff(off, dir). </pre>

<p>To:</p>

<pre>-4- Effects: If fail() != true, executes rdbuf()-&gt;pubseekoff(off, dir, ios_base::out). </pre>

<p><i>[Dublin: Dietmar Kühl thinks this is probably correct, but would
like the opinion of more iostream experts before taking action.]</i></p>

<p><i>[Tokyo: Reviewed by the LWG. PJP noted that although his docs are
incorrect, his implementation already implements the Proposed
Resolution.]</i></p>

<p><i>[Post-Tokyo: Matt Austern comments:<br>
Is it a problem with basic_istream and basic_ostream, or is it a problem
with basic_stringbuf?
We could resolve the issue either by changing basic_istream and
basic_ostream, or by changing basic_stringbuf. I prefer the latter
change (or maybe both changes): I don't see any reason for the standard to
require that std::stringbuf s(std::string("foo"), std::ios_base::in);
s.pubseekoff(0, std::ios_base::beg); must fail.<br>
This requirement is a bit weird. There's no similar requirement
for basic_streambuf&lt;&gt;::seekpos, or for basic_filebuf&lt;&gt;::seekoff or
basic_filebuf&lt;&gt;::seekpos.]</i></p>
<hr>
<a name="137"><h3>137.&nbsp;Do use_facet and has_facet look in the global locale?</h3></a><p><b>Section:</b>&nbsp;22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;17 Mar 1999</p>
<p>Section 22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a> says:</p>

<p>-4- In the call to use_facet&lt;Facet&gt;(loc), the type argument
chooses a facet, making available all members of the named type. If
Facet is not present in a locale (or, failing that, in the global
locale), it throws the standard exception bad_cast. A C++ program can
check if a locale implements a particular facet with the template
function has_facet&lt;Facet&gt;(). </p>

<p>This contradicts the specification given in section 
22.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.global.templates"> [lib.locale.global.templates]</a>:
<br><br>
template &lt;class&nbsp; Facet&gt; const&nbsp; Facet&amp; use_facet(const
locale&amp;&nbsp; loc); <br>
<br>
-1- Get a reference to a facet of a locale. <br>
-2- Returns: a reference to the corresponding facet of loc, if present. <br>
-3- Throws: bad_cast if has_facet&lt;Facet&gt;(loc) is false. <br>
-4- Notes: The reference returned remains valid at least as long as any copy of loc exists
</p>
<p><b>Proposed resolution:</b></p>
<p>Remove the phrase "(or, failing that, in the global locale)"
from section 22.1.1. </p>
<p><b>Rationale:</b></p>
<p>Needed for consistency with the way locales are handled elsewhere
in the standard.</p>
<hr>
<a name="139"><h3>139.&nbsp;Optional sequence operation table description unclear</h3></a><p><b>Section:</b>&nbsp;23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;30 Mar 1999</p>
<p>The sentence introducing the Optional sequence operation table
(23.1.1 paragraph 12) has two problems:</p>

<p>A. It says ``The operations in table 68 are provided only for the containers for which
they take constant time.''<br>
<br>
That could be interpreted in two ways, one of them being ``Even though table 68 shows
particular operations as being provided, implementations are free to omit them if they
cannot implement them in constant time.''<br>
<br>
B. That paragraph says nothing about amortized constant time, and it should.&nbsp;</p>
<p><b>Proposed resolution:</b></p>
<p>Replace the wording in 23.1.1 paragraph 12&nbsp; which begins ``The operations in table 68 are provided only..."
with:</p>

<blockquote>
  <p>Table 68 lists sequence operations that are provided for some types of sequential
  containers but not others. An implementation shall provide these operations for all
  container types shown in the ``container'' column, and shall implement them so as to take
  amortized constant time.</p>
</blockquote>
<hr>
<a name="141"><h3>141.&nbsp;basic_string::find_last_of, find_last_not_of say pos instead of xpos</h3></a><p><b>Section:</b>&nbsp;21.3.6.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::find.last.of"> [lib.string::find.last.of]</a>, 21.3.6.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::find.last.not.of"> [lib.string::find.last.not.of]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Arch Robison&nbsp; <b>Date:</b>&nbsp;28 Apr 1999</p>
<p>Sections 21.3.6.4 paragraph 1 and 21.3.6.6 paragraph 1 surely have misprints where they
say:<br>
<br>
&#8212; <tt>xpos &lt;= pos</tt> and <tt>pos &lt; size();</tt></p>

<p>Surely the document meant to say ``<tt>xpos &lt; size()</tt>'' in both places.</p>

<p><i>[Judy Ward also sent in this issue for 21.3.6.4 with the same
proposed resolution.]</i></p>
<p><b>Proposed resolution:</b></p>
<p>Change Sections 21.3.6.4 paragraph 1 and 21.3.6.6 paragraph 1, the line which says:<br>
<br>
&#8212; <tt>xpos &lt;= pos</tt> and <tt>pos &lt; size();<br>
<br>
</tt>to:<br>
<tt><br>
</tt>&#8212; <tt>xpos &lt;= pos</tt> and <tt>xpos &lt; size();</tt></p>
<hr>
<a name="142"><h3>142.&nbsp;lexicographical_compare complexity wrong</h3></a><p><b>Section:</b>&nbsp;25.3.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.lex.comparison"> [lib.alg.lex.comparison]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;20 Jun 1999</p>
<p>The lexicographical_compare complexity is specified as:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp; "At most min((last1 - first1), (last2 - first2))
applications of the corresponding comparison."<br>
<br>
The best I can do is twice that expensive.</p>

<p>Nicolai Josuttis comments in lib-6862: You mean, to check for
equality you have to check both &lt; and &gt;? Yes, IMO you are
right! (and Matt states this complexity in his book)</p>

<p><b>Proposed resolution:</b></p>
<p>Change 25.3.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.lex.comparison"> [lib.alg.lex.comparison]</a> complexity to:</p>
    <blockquote>
    At most <tt>2*min((last1 - first1), (last2 - first2))</tt>
    applications of the corresponding comparison.
    </blockquote>

<p>Change the example at the end of paragraph 3 to read:</p>
    <blockquote>
    [Example:<br>
    <br>
    &nbsp;&nbsp;&nbsp; for ( ; first1 != last1 &amp;&amp; first2 != last2 ;
    ++first1, ++first2) {<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (*first1 &lt; *first2) return true;<br>
    &nbsp;&nbsp;&nbsp;&nbsp;&nbsp; if (*first2 &lt; *first1) return false;<br>
    &nbsp;&nbsp;&nbsp; }<br>
    &nbsp;&nbsp;&nbsp; return first1 == last1 &amp;&amp; first2 != last2;<br>
    &nbsp;&nbsp;&nbsp;<br>
    --end example]
    </blockquote>
<hr>
<a name="144"><h3>144.&nbsp;Deque constructor complexity wrong </h3></a><p><b>Section:</b>&nbsp;23.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.array.cons"> [lib.array.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Herb Sutter&nbsp; <b>Date:</b>&nbsp;9 May 1999</p>
<p>In 23.2.1.1 paragraph 6, the deque ctor that takes an iterator range appears
to have complexity requirements which are incorrect, and which contradict the
complexity requirements for insert(). I suspect that the text in question,
below, was taken from vector:</p>
<blockquote>
  <p>Complexity: If the iterators first and last are forward iterators,
  bidirectional iterators, or random access iterators the constructor makes only
  N calls to the copy constructor, and performs no reallocations, where N is
  last - first.</p>
</blockquote>
<p>The word "reallocations" does not really apply to deque. Further,
all of the following appears to be spurious:</p>
<blockquote>
  <p>It makes at most 2N calls to the copy constructor of T and log N
  reallocations if they are input iterators.1)</p>
  <p>1) The complexity is greater in the case of input iterators because each
  element must be added individually: it is impossible to determine the distance
  between first abd last before doing the copying.</p>
</blockquote>
<p>This makes perfect sense for vector, but not for deque. Why should deque gain
an efficiency advantage from knowing in advance the number of elements to
insert?</p>
<p><b>Proposed resolution:</b></p>
<p>In 23.2.1.1 paragraph 6, replace the Complexity description, including the
footnote, with the following text (which also corrects the "abd"
typo):</p>
<blockquote>
  <p>Complexity: Makes last - first calls to the copy constructor of T.</p>
</blockquote>
<hr>
<a name="146"><h3>146.&nbsp;complex&lt;T&gt; Inserter and Extractor need sentries</h3></a><p><b>Section:</b>&nbsp;26.3.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.ops"> [lib.complex.ops]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;12 May 1999</p>
<p>The <u> extractor</u> for complex numbers is specified as:&nbsp;</p>

<blockquote>

<p>     template&lt;class T, class charT, class traits&gt;&nbsp;<br>
     basic_istream&lt;charT, traits&gt;&amp;&nbsp;<br>
     operator&gt;&gt;(basic_istream&lt;charT, traits&gt;&amp;  is, complex&lt;T&gt;&amp;  x);<br>
&nbsp;<br>
Effects: Extracts a complex number x of the form: u, (u), or (u,v),
where u is the real part and v is the imaginary part
(lib.istream.formatted).&nbsp;<br>
Requires: The input values be convertible to T. If bad input is
encountered, calls is.setstate(ios::failbit) (which may throw
ios::failure (lib.iostate.flags).&nbsp;<br>
Returns: is .</p>

</blockquote>
<p>Is it intended that the extractor for complex numbers does not skip
whitespace, unlike all other extractors in the standard library do?
Shouldn't a sentry be used?&nbsp;<br>
<br>
The <u>inserter</u> for complex numbers is specified as:</p>

<blockquote>

<p>     template&lt;class T, class charT, class traits&gt;&nbsp;<br>
     basic_ostream&lt;charT, traits&gt;&amp;&nbsp;<br>
     operator&lt;&lt;(basic_ostream&lt;charT, traits&gt;&amp;  o, const complex&lt;T&gt;&amp;  x);<br>
<br>
Effects: inserts the complex number x onto the stream o as if it were implemented as follows:<br>
<br>
     template&lt;class T, class charT, class traits&gt;&nbsp;<br>
     basic_ostream&lt;charT, traits&gt;&amp;&nbsp;<br>
     operator&lt;&lt;(basic_ostream&lt;charT, traits&gt;&amp; o, const complex&lt;T&gt;&amp; x)&nbsp;<br>
     {&nbsp;<br>
             basic_ostringstream&lt;charT, traits&gt; s;&nbsp;<br>
             s.flags(o.flags());&nbsp;<br>
             s.imbue(o.getloc());&nbsp;<br>
             s.precision(o.precision());&nbsp;<br>
             s &lt;&lt; '(' &lt;&lt; x.real() &lt;&lt; "," &lt;&lt; x.imag() &lt;&lt; ')';&nbsp;<br>
             return o &lt;&lt; s.str();&nbsp;<br>
     }</p>

</blockquote>

<p>Is it intended that the inserter for complex numbers ignores the
field width and does not do any padding? If, with the suggested
implementation above, the field width were set in the stream then the
opening parentheses would be adjusted, but the rest not, because the
field width is reset to zero after each insertion.</p>

<p>I think that both operations should use sentries, for sake of
consistency with the other inserters and extractors in the
library. Regarding the issue of padding in the inserter, I don't know
what the intent was.&nbsp;</p>
<p><b>Proposed resolution:</b></p>
<p>After 26.3.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex.ops"> [lib.complex.ops]</a> paragraph 14 (operator&gt;&gt;), add a
Notes clause:</p>

<blockquote>

<p>Notes: This extraction is performed as a series of simpler
extractions. Therefore, the skipping of whitespace is specified to be the
same for each of the simpler extractions.</p>

</blockquote>
<p><b>Rationale:</b></p>
<p>For extractors, the note is added to make it clear that skipping whitespace
follows an "all-or-none" rule.</p>

<p>For inserters, the LWG believes there is no defect; the standard is correct
as written.</p>
<hr>
<a name="147"><h3>147.&nbsp;Library Intro refers to global functions that aren't global</h3></a><p><b>Section:</b>&nbsp;17.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.global.functions"> [lib.global.functions]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Lois Goldthwaite&nbsp; <b>Date:</b>&nbsp;4 Jun 1999</p>
<p>The library had many global functions until 17.4.1.1 [lib.contents]
paragraph 2 was added: </p>

<blockquote>

<p>All library entities except macros, operator new and operator
delete are defined within the namespace std or namespaces nested
within namespace std. </p>

</blockquote>

<p>It appears "global function" was never updated in the following: </p>

<blockquote>

<p>17.4.4.3 - Global functions [lib.global.functions]<br>
<br>
-1- It is unspecified whether any global functions in the C++ Standard
Library are defined as inline (dcl.fct.spec).<br>
<br>
-2- A call to a global function signature described in Clauses
lib.language.support through lib.input.output behaves the same as if
the implementation declares no additional global function
signatures.*<br>
<br>
    [Footnote: A valid C++ program always calls the expected library
    global function. An implementation may also define additional
    global functions that would otherwise not be called by a valid C++
    program. --- end footnote]<br>
<br>
-3- A global function cannot be declared by the implementation as
taking additional default arguments.&nbsp;<br>
<br>
17.4.4.4 - Member functions [lib.member.functions]<br>
<br>
-2- An implementation can declare additional non-virtual member
function signatures within a class: </p>

  <blockquote>

<p>-- by adding arguments with default values to a member function
signature; The same latitude does not extend to the implementation of
virtual or global functions, however. </p>

  </blockquote>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>     Change "global" to "global or non-member" in:</p>
<blockquote>
  <p>17.4.4.3 [lib.global.functions] section title,<br>
  17.4.4.3 [lib.global.functions] para 1,<br>
  17.4.4.3 [lib.global.functions] para 2 in 2 places plus 2 
           places in the footnote,<br>
  17.4.4.3 [lib.global.functions] para 3,<br>
  17.4.4.4 [lib.member.functions] para 2</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>
Because operator new and delete are global, the proposed resolution
was changed from "non-member" to "global or non-member.
</p>
<hr>
<a name="148"><h3>148.&nbsp;Functions in the example facet BoolNames should be const</h3></a><p><b>Section:</b>&nbsp;22.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Jeremy Siek&nbsp; <b>Date:</b>&nbsp;3 Jun 1999</p>
<p>In 22.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a> paragraph 13, the do_truename() and
do_falsename() functions in the example facet BoolNames should be
const. The functions they are overriding in
numpunct_byname&lt;char&gt; are const. </p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a> paragraph 13, insert "const" in
two places:</p>
<blockquote>
  <p><tt>string do_truename() const { return "Oui Oui!"; }<br>
  string do_falsename() const { return "Mais Non!"; }</tt></p>
</blockquote>
<hr>
<a name="150"><h3>150.&nbsp;Find_first_of says integer instead of iterator </h3></a><p><b>Section:</b>&nbsp;25.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.find.first.of"> [lib.alg.find.first.of]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt McClure&nbsp; <b>Date:</b>&nbsp;30 Jun 1999</p>
<p><b>Proposed resolution:</b></p>
<p>Change 25.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.find.first.of"> [lib.alg.find.first.of]</a> paragraph 2 from:</p>

<blockquote>
<p>Returns: The first iterator i in the range [first1, last1) such
that for some <u>integer</u> j in the range [first2, last2) ...</p>
</blockquote>

<p>to:</p>

<blockquote>
<p>Returns: The first iterator i in the range [first1, last1) such
that for some iterator j in the range [first2, last2) ...</p>
</blockquote>
<hr>
<a name="151"><h3>151.&nbsp;Can't currently clear() empty container</h3></a><p><b>Section:</b>&nbsp;23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Ed Brey&nbsp; <b>Date:</b>&nbsp;21 Jun 1999</p>
<p>For both sequences and associative containers, a.clear() has the
semantics of erase(a.begin(),a.end()), which is undefined for an empty
container since erase(q1,q2) requires that q1 be dereferenceable
(23.1.1,3 and 23.1.2,7).  When the container is empty, a.begin() is
not dereferenceable.<br>
<br>
The requirement that q1 be unconditionally dereferenceable causes many
operations to be intuitively undefined, of which clearing an empty
container is probably the most dire.<br>
<br>
Since q1 and q2 are only referenced in the range [q1, q2), and [q1,
q2) is required to be a valid range, stating that q1 and q2 must be
iterators or certain kinds of iterators is unnecessary.
</p>
<p><b>Proposed resolution:</b></p>
<p>In 23.1.1, paragraph 3, change:</p>
<blockquote>
  <p>p and q2 denote valid iterators to a, q <u> and q1</u> denote valid dereferenceable iterators to a, [q1, q2) denotes a valid range</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>p denotes a valid iterator to a, q denotes a valid dereferenceable iterator to a, [q1, q2) denotes a valid range<u>
  in a</u></p>
</blockquote>
<p>In 23.1.2, paragraph 7, change:</p>
<blockquote>
  <p>p and q2 are valid iterators to a, q <u> and q1</u> are valid dereferenceable
  iterators to a, [q1, q2) is a valid range</p>
</blockquote>
<p>to</p>
<blockquote>
  <p>p is a valid iterator to a, q is a valid dereferenceable iterator to a, [q1, q2) is a valid range
  <u>into a</u></p>
</blockquote>
<hr>
<a name="152"><h3>152.&nbsp;Typo in <tt>scan_is()</tt> semantics</h3></a><p><b>Section:</b>&nbsp;22.2.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The semantics of <tt>scan_is()</tt> (paragraphs 4 and 6) is not exactly described
because there is no function <tt>is()</tt> which only takes a character as
argument. Also, in the effects clause (paragraph 3), the semantic is also kept
vague.</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a> paragraphs 4 and 6, change the returns
clause from:</p>
<blockquote>
  <p>"... such that <tt>is(*p)</tt>
would..."</p>
</blockquote>
<p>to:&nbsp; "... such that <tt>is(m, *p)</tt>
 would...."</p>
<hr>
<a name="153"><h3>153.&nbsp;Typo in <tt>narrow()</tt> semantics</h3></a><p><b>Section:</b>&nbsp;22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The description of the array version of <tt>narrow()</tt> (in
paragraph 11) is flawed: There is no member <tt>do_narrow()</tt> which
takes only three arguments because in addition to the range a default
character is needed.</p>

<p>Additionally, for both <tt>widen</tt> and <tt>narrow</tt> we have
two signatures followed by a <b>Returns</b> clause that only addresses
one of them.</p>

<p><b>Proposed resolution:</b></p>
<p>Change the returns clause in 22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a>
paragraph 10 from:</p>
<p>&nbsp;&nbsp;&nbsp; Returns: do_widen(low, high, to).</p>

<p>to:</p>
<p>&nbsp;&nbsp;&nbsp; Returns: do_widen(c) or do_widen(low, high, to), 
respectively.</p>

<p>Change 22.2.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.ctype.char.members"> [lib.facet.ctype.char.members]</a> paragraph 10 and 11 from:</p>
<pre>        char        narrow(char c, char /*dfault*/) const;
        const char* narrow(const char* low, const char* high,
                           char /*dfault*/, char* to) const;</pre>
<pre>        Returns: do_narrow(low, high, to).</pre>
<p>to:</p>
<pre>        char        narrow(char c, char dfault) const;
        const char* narrow(const char* low, const char* high,
                           char dfault, char* to) const;</pre>
<pre>        Returns: do_narrow(c, dfault) or
                 do_narrow(low, high, dfault, to), respectively.</pre>

<p><i>[Kona: 1) the problem occurs in additional places, 2) a user
defined version could be different.]</i></p>

<p><i>[Post-Tokyo: Dietmar provided the above wording at the request of
the LWG. He could find no other places the problem occurred. He
asks for clarification of the Kona "a user defined
version..." comment above.  Perhaps it was a circuitous way of
saying "dfault" needed to be uncommented?]</i></p>

<p><i>[Post-Toronto: the issues list maintainer has merged in the
proposed resolution from issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#207">207</a>, which addresses the
same paragraphs.]</i></p>
<hr>
<a name="154"><h3>154.&nbsp;Missing <tt>double</tt> specifier for <tt>do_get()</tt>
</h3></a><p><b>Section:</b>&nbsp;22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The table in paragraph 7 for the length modifier does not list the length
modifier <tt>l</tt> to be applied if the type is <tt>double</tt>. Thus, the
standard asks the implementation to do undefined things when using <tt>scanf()</tt>
(the missing length modifier for <tt>scanf()</tt> when scanning <tt>double</tt>s
is actually a problem I found quite often in production code, too).</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>, paragraph 7, add a row in the Length
Modifier table to say that for <tt>double</tt> a length modifier
<tt>l</tt> is to be used.</p>
<p><b>Rationale:</b></p>
<p>The standard makes an embarrassing beginner's mistake.</p>
<hr>
<a name="155"><h3>155.&nbsp;Typo in naming the class defining the class <tt>Init</tt>
</h3></a><p><b>Section:</b>&nbsp;27.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostream.objects"> [lib.iostream.objects]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>There are conflicting statements about where the class
<tt>Init</tt> is defined. According to 27.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostream.objects"> [lib.iostream.objects]</a> paragraph 2
it is defined as <tt>basic_ios::Init</tt>, according to 27.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a> it is defined as <tt>ios_base::Init</tt>.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 27.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostream.objects"> [lib.iostream.objects]</a> paragraph 2 from
"<tt>basic_ios::Init"</tt> to
"<tt>ios_base::Init"</tt>.</p>
<p><b>Rationale:</b></p>
<p>Although not strictly wrong, the standard was misleading enough to warrant
the change.</p>
<hr>
<a name="156"><h3>156.&nbsp;Typo in <tt>imbue()</tt> description</h3></a><p><b>Section:</b>&nbsp;27.4.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.locales"> [lib.ios.base.locales]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>There is a small discrepancy between the declarations of
<tt>imbue()</tt>: in 27.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base"> [lib.ios.base]</a> the argument is passed as
<tt>locale const&amp;</tt> (correct), in 27.4.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.locales"> [lib.ios.base.locales]</a> it
is passed as <tt>locale const</tt> (wrong).</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.4.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.locales"> [lib.ios.base.locales]</a> change the <tt>imbue</tt> argument
from "<tt>locale const" to "locale
const&amp;".</tt></p>
<hr>
<a name="158"><h3>158.&nbsp;Underspecified semantics for <tt>setbuf()</tt>
</h3></a><p><b>Section:</b>&nbsp;27.5.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.buffer"> [lib.streambuf.virt.buffer]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The default behavior of <tt>setbuf()</tt> is described only for the
situation that <tt>gptr() != 0 &amp;&amp; gptr() != egptr()</tt>:
namely to do nothing.  What has to be done in other situations&nbsp;
is not described although there is actually only one reasonable
approach, namely to do nothing, too.</p> 

<p>Since changing the buffer would almost certainly mess up most
buffer management of derived classes unless these classes do it
themselves, the default behavior of <tt>setbuf()</tt> should always be
to do nothing.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 27.5.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.buffer"> [lib.streambuf.virt.buffer]</a>, paragraph 3, Default behavior,
to: "Default behavior: Does nothing. Returns this."</p>
<hr>
<a name="159"><h3>159.&nbsp;Strange use of <tt>underflow()</tt>
</h3></a><p><b>Section:</b>&nbsp;27.5.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.get"> [lib.streambuf.virt.get]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The description of the meaning of the result of
<tt>showmanyc()</tt> seems to be rather strange: It uses calls to
<tt>underflow()</tt>. Using <tt>underflow()</tt> is strange because
this function only reads the current character but does not extract
it, <tt>uflow()</tt> would extract the current character. This should
be fixed to use <tt>sbumpc()</tt> instead.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 27.5.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.get"> [lib.streambuf.virt.get]</a> paragraph 1,
<tt>showmanyc()</tt>returns clause, by replacing the word
"supplied" with the words "extracted from the
stream".</p>
<hr>
<a name="160"><h3>160.&nbsp;Typo: Use of non-existing function <tt>exception()</tt>
</h3></a><p><b>Section:</b>&nbsp;27.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream"> [lib.istream]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The paragraph 4 refers to the function <tt>exception()</tt> which
is not defined. Probably, the referred function is
<tt>basic_ios&lt;&gt;::exceptions()</tt>.</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream"> [lib.istream]</a>, 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>, paragraph 1,
27.6.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream"> [lib.ostream]</a>, paragraph 3, and 27.6.2.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.formatted.reqmts"> [lib.ostream.formatted.reqmts]</a>,
paragraph 1, change "<tt>exception()" to
"exceptions()"</tt>.</p>

<p><i>[Note to Editor: "exceptions" with an "s"
is the correct spelling.]</i></p>
<hr>
<a name="161"><h3>161.&nbsp;Typo: <tt>istream_iterator</tt> vs. <tt>istreambuf_iterator</tt>
</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.arithmetic"> [lib.istream.formatted.arithmetic]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The note in the second paragraph pretends that the first argument
is an object of type <tt>istream_iterator</tt>. This is wrong: It is
an object of type <tt>istreambuf_iterator</tt>.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 27.6.1.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.arithmetic"> [lib.istream.formatted.arithmetic]</a> from:</p>
<blockquote>
  <p>The first argument provides an object of the istream_iterator class...</p>
</blockquote>
<p>to</p>
<blockquote>
  <p>The first argument provides an object of the istreambuf_iterator class...</p>
</blockquote>
<hr>
<a name="164"><h3>164.&nbsp;do_put() has apparently unused fill argument</h3></a><p><b>Section:</b>&nbsp;22.2.5.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.time.put.virtuals"> [lib.locale.time.put.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;23 Jul 1999</p>
<p>In 22.2.5.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.time.put.virtuals"> [lib.locale.time.put.virtuals]</a> the do_put() function is specified
as taking a fill character as an argument, but the description of the
function does not say whether the character is used at all and, if so,
in which way. The same holds for any format control parameters that
are accessible through the ios_base&amp; argument, such as the
adjustment or the field width. Is strftime() supposed to use the fill
character in any way? In any case, the specification of
time_put.do_put() looks inconsistent to me.<br> <br> Is the
signature of do_put() wrong, or is the effects clause incomplete?</p>
<p><b>Proposed resolution:</b></p>
<p>Add the following note after 22.2.5.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.time.put.virtuals"> [lib.locale.time.put.virtuals]</a>
paragraph 2:</p>
<blockquote>
  <p>  [Note: the <tt>fill</tt> argument may be used in the implementation-defined  formats, or by derivations.  A space character is a reasonable default
  for this argument. --end Note]</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>The LWG felt that while the normative text was correct,
users need some guidance on what to pass for the <tt>fill</tt>
argument since the standard doesn't say how it's used.</p>
<hr>
<a name="165"><h3>165.&nbsp;<tt>xsputn()</tt>, <tt>pubsync()</tt> never called by <tt>basic_ostream</tt> members?</h3></a><p><b>Section:</b>&nbsp;27.6.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream"> [lib.ostream]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>Paragraph 2 explicitly states that none of the <tt>basic_ostream</tt>
functions falling into one of the groups "formatted output functions"
and "unformatted output functions" calls any stream buffer function
which might call a virtual function other than <tt>overflow()</tt>. Basically
this is fine but this implies that <tt>sputn()</tt> (this function would call
the virtual function <tt>xsputn()</tt>) is never called by any of the standard
output functions. Is this really intended? At minimum it would be convenient to
call <tt>xsputn()</tt> for strings... Also, the statement that <tt>overflow()</tt>
is the only virtual member of <tt>basic_streambuf</tt> called is in conflict
with the definition of <tt>flush()</tt> which calls <tt>rdbuf()-&gt;pubsync()</tt>
and thereby the virtual function <tt>sync()</tt> (<tt>flush()</tt> is listed
under "unformatted output functions").</p>
<p>In addition, I guess that the sentence starting with "They may use other
public members of <tt>basic_ostream</tt> ..." probably was intended to
start with "They may use other public members of <tt>basic_streamuf</tt>..."
although the problem with the virtual members exists in both cases.</p>
<p>I see two obvious resolutions:</p>
<ol>
  <li>state in a footnote that this means that <tt>xsputn()</tt> will never be
    called by any ostream member and that this is intended.</li>
  <li>relax the restriction and allow calling <tt>overflow()</tt> and <tt>xsputn()</tt>.
    Of course, the problem with <tt>flush()</tt> has to be resolved in some way.</li>
</ol>
<p><b>Proposed resolution:</b></p>
<p>Change the last sentence of 27.6.2.1 (lib.ostream) paragraph 2 from:</p>
<blockquote>
  <p>They may use other public members of basic_ostream except that they do not
  invoke any virtual members of rdbuf() except overflow().</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>They may use other public members of basic_ostream except that they shall
  not invoke any virtual members of rdbuf() except overflow(), xsputn(), and
  sync().</p>
</blockquote>

<p><i>[Kona: the LWG believes this is a problem. Wish to ask Jerry or
PJP why the standard is written this way.]</i></p>

<p><i>[Post-Tokyo: Dietmar supplied wording at the request of the
LWG. He comments: The rules can be made a little bit more specific if
necessary be explicitly spelling out what virtuals are allowed to be
called from what functions and eg to state specifically that flush()
is allowed to call sync() while other functions are not.]</i></p>
<hr>
<a name="167"><h3>167.&nbsp;Improper use of <tt>traits_type::length()</tt>
</h3></a><p><b>Section:</b>&nbsp;27.6.2.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters.character"> [lib.ostream.inserters.character]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>Paragraph 4 states that the length is determined using
<tt>traits::length(s)</tt>.  Unfortunately, this function is not
defined for example if the character type is <tt>wchar_t</tt> and the
type of <tt>s</tt> is <tt>char const*</tt>. Similar problems exist if
the character type is <tt>char</tt> and the type of <tt>s</tt> is
either <tt>signed char const*</tt> or <tt>unsigned char
const*</tt>.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 27.6.2.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters.character"> [lib.ostream.inserters.character]</a> paragraph 4 from:</p>
<blockquote>
  <p>Effects: Behaves like an formatted inserter (as described in
  lib.ostream.formatted.reqmts) of out. After a sentry object is
  constructed it inserts characters. The number of characters starting
  at s to be inserted is traits::length(s). Padding is determined as
  described in lib.facet.num.put.virtuals. The traits::length(s)
  characters starting at s are widened using out.widen
  (lib.basic.ios.members). The widened characters and any required
  padding are inserted into out. Calls width(0).</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>Effects: Behaves like a formatted inserter (as described in
  lib.ostream.formatted.reqmts) of out. After a sentry object is
  constructed it inserts <i>n</i> characters starting at <i>s</i>,
  where <i>n</i> is the number that would be computed as if by:</p>
  <ul>
  <li>traits::length(s) for the overload where the first argument is of
    type basic_ostream&lt;charT, traits&gt;&amp; and the second is
    of type const charT*, and also for the overload where the first
    argument is of type basic_ostream&lt;char, traits&gt;&amp; and
    the second is of type const char*.</li>
  <li>std::char_traits&lt;char&gt;::length(s) 
    for the overload where the first argument is of type 
    basic_ostream&lt;charT, traits&gt;&amp; and the second is of type
    const char*.</li>
  <li>traits::length(reinterpret_cast&lt;const char*&gt;(s)) 
    for the other two overloads.</li>
  </ul>
  <p>Padding is determined as described in
  lib.facet.num.put.virtuals. The <i>n</i> characters starting at
  <i>s</i> are widened using out.widen (lib.basic.ios.members).  The
  widened characters and any required padding are inserted into
  out. Calls width(0).</p>
</blockquote>

<p><i>[Santa Cruz: Matt supplied new wording]</i></p>

<p><i>[Kona: changed "where <i>n</i> is" to " where <i>n</i> is the
  number that would be computed as if by"]</i></p> 

<p><b>Rationale:</b></p>
<p>We have five separate cases.  In two of them we can use the
user-supplied traits class without any fuss.  In the other three we
try to use something as close to that user-supplied class as possible.
In two cases we've got a traits class that's appropriate for
char and what we've got is a const signed char* or a const
unsigned char*; that's close enough so we can just use a reinterpret
cast, and continue to use the user-supplied traits class.  Finally,
there's one case where we just have to give up: where we've got a
traits class for some arbitrary charT type, and we somehow have to
deal with a const char*.  There's nothing better to do but fall back
to char_traits&lt;char&gt;</p>
<hr>
<a name="168"><h3>168.&nbsp;Typo: formatted vs. unformatted</h3></a><p><b>Section:</b>&nbsp;27.6.2.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.unformatted"> [lib.ostream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The first paragraph begins with a descriptions what has to be done
in <i>formatted</i> output functions. Probably this is a typo and the
paragraph really want to describe unformatted output functions...</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.6.2.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.unformatted"> [lib.ostream.unformatted]</a> paragraph 1, the first and last
sentences, change the word "formatted" to
"unformatted":</p>
<blockquote>
  <p>"Each <b>unformatted </b> output function begins ..."<br>
  "... value specified for the <b>unformatted </b>  output 
  function."</p>
</blockquote>
<hr>
<a name="169"><h3>169.&nbsp;Bad efficiency of <tt>overflow()</tt> mandated</h3></a><p><b>Section:</b>&nbsp;27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>Paragraph 8, Notes, of this section seems to mandate an extremely
inefficient way of buffer handling for <tt>basic_stringbuf</tt>,
especially in view of the restriction that <tt>basic_ostream</tt>
member functions are not allowed to use <tt>xsputn()</tt> (see 27.6.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream"> [lib.ostream]</a>): For each character to be inserted, a new buffer
is to be created.</p> 
<p>Of course, the resolution below requires some handling of
simultaneous input and output since it is no longer possible to update
<tt>egptr()</tt> whenever <tt>epptr()</tt> is changed. A possible
solution is to handle this in <tt>underflow()</tt>.</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a> paragraph 8, Notes, insert the words
"at least" as in the following:</p>
<blockquote>
  <p>To make a write position available, the function reallocates (or initially
  allocates) an array object with a sufficient number of elements to hold the
  current array object (if any), plus <b>at least</b> one additional write
  position.</p>
</blockquote>
<hr>
<a name="170"><h3>170.&nbsp;Inconsistent definition of <tt>traits_type</tt>
</h3></a><p><b>Section:</b>&nbsp;27.7.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringstream"> [lib.stringstream]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>The classes <tt>basic_stringstream</tt> (27.7.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringstream"> [lib.stringstream]</a>),
<tt>basic_istringstream</tt> (27.7.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istringstream"> [lib.istringstream]</a>), and
<tt>basic_ostringstream</tt> (27.7.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostringstream"> [lib.ostringstream]</a>) are inconsistent
in their definition of the type <tt>traits_type</tt>: For
<tt>istringstream</tt>, this type is defined, for the other two it is
not. This should be consistent.</p>
<p><b>Proposed resolution:</b></p>
<p><b>Proposed resolution:</b></p> <p>To the declarations of
<tt>basic_ostringstream</tt> (27.7.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostringstream"> [lib.ostringstream]</a>) and
<tt>basic_stringstream</tt> (27.7.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringstream"> [lib.stringstream]</a>) add:</p>
<blockquote>
<pre>typedef traits traits_type;</pre>
</blockquote>
<hr>
<a name="171"><h3>171.&nbsp;Strange <tt>seekpos()</tt> semantics due to joint position</h3></a><p><b>Section:</b>&nbsp;27.8.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Jul 1999</p>
<p>Overridden virtual functions, seekpos()</p> <p>In 27.8.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf"> [lib.filebuf]</a> paragraph 3, it is stated that a joint input and
output position is maintained by <tt>basic_filebuf</tt>. Still, the
description of <tt>seekpos()</tt> seems to talk about different file
positions. In particular, it is unclear (at least to me) what is
supposed to happen to the output buffer (if there is one) if only the
input position is changed. The standard seems to mandate that the
output buffer is kept and processed as if there was no positioning of
the output position (by changing the input position). Of course, this
can be exactly what you want if the flag <tt>ios_base::ate</tt> is
set. However, I think, the standard should say something like
this:</p>
<ul>
  <li>If <tt>(which &amp; mode) == 0</tt> neither read nor write position is
    changed and the call fails. Otherwise, the joint read and write position is
    altered to correspond to <tt>sp</tt>.</li>
  <li>If there is an output buffer, the output sequences is updated and any
    unshift sequence is written before the position is altered.</li>
  <li>If there is an input buffer, the input sequence is updated after the
    position is altered.</li>
</ul>
<p>Plus the appropriate error handling, that is...</p>
<p><b>Proposed resolution:</b></p>
<p>Change the unnumbered paragraph in 27.8.1.4 (lib.filebuf.virtuals) before
paragraph 14 from:</p>
<blockquote>
  <p>pos_type seekpos(pos_type sp, ios_base::openmode = ios_base::in |
  ios_base::out);</p>
  <p>Alters the file position, if possible, to correspond to the position stored
  in sp (as described below).</p>
  <p>- if (which&amp;ios_base::in)!=0, set the file position to sp, then update
  the input sequence</p>
  <p>- if (which&amp;ios_base::out)!=0, then update the output sequence, write
  any unshift sequence, and set the file position to sp.</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>pos_type seekpos(pos_type sp, ios_base::openmode = ios_base::in |
  ios_base::out);</p>
  <p>Alters the file position, if possible, to correspond to the position stored
  in sp (as described below). Altering the file position performs as follows:</p>
  <p>1. if (om &amp; ios_base::out)!=0, then update the output sequence and
  write any unshift sequence;</p>
  <p>2. set the file position to sp;</p>
  <p>3. if (om &amp; ios_base::in)!=0, then update the input sequence;</p>
  <p>where om is the open mode passed to the last call to open(). The operation
  fails if is_open() returns false.</p>
</blockquote>

<p><i>[Kona: Dietmar is working on a proposed resolution.]</i></p>
<p><i>[Post-Tokyo: Dietmar supplied the above wording.]</i></p>
<hr>
<a name="172"><h3>172.&nbsp;Inconsistent types for <tt>basic_istream::ignore()</tt>
</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Greg Comeau, Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;23 Jul 1999</p>
<p>In 27.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream"> [lib.istream]</a> the function
<tt>ignore()</tt> gets an object of type <tt>streamsize</tt> as first
argument. However, in 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>
paragraph 23 the first argument is of type <tt>int.</tt></p>

<p>As far as I can see this is not really a contradiction because
everything is consistent if <tt>streamsize</tt> is typedef to be
<tt>int</tt>. However, this is almost certainly not what was
intended. The same thing happened to <tt>basic_filebuf::setbuf()</tt>,
as described in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#173">173</a>.</p>

<p>Darin Adler also
submitted this issue, commenting: Either 27.6.1.1 should be modified
to show a first parameter of type int, or 27.6.1.3 should be modified
to show a first parameter of type streamsize and use
numeric_limits&lt;streamsize&gt;::max.</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a> paragraph 23 and 24, change both uses
of <tt>int</tt> in the description of <tt>ignore()</tt> to
<tt>streamsize</tt>.</p>
<hr>
<a name="173"><h3>173.&nbsp;Inconsistent types for <tt>basic_filebuf::setbuf()</tt>
</h3></a><p><b>Section:</b>&nbsp;27.8.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Greg Comeau, Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;23 Jul 1999</p>

<p>
In 27.8.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf"> [lib.filebuf]</a> the function <tt>setbuf()</tt> gets an
object of type <tt>streamsize</tt> as second argument. However, in
27.8.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a> paragraph 9 the second argument is of type
<tt>int</tt>.
</p>

<p>
As far as I can see this is not really a contradiction because
everything is consistent if <tt>streamsize</tt> is typedef to be
<tt>int</tt>. However, this is almost certainly not what was
intended. The same thing happened to <tt>basic_istream::ignore()</tt>,
as described in issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#172">172</a>.
</p>

<p><b>Proposed resolution:</b></p>
<p>In 27.8.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.virtuals"> [lib.filebuf.virtuals]</a> paragraph 9, change all uses of
<tt>int</tt> in the description of <tt>setbuf()</tt> to
<tt>streamsize</tt>.</p>
<hr>
<a name="174"><h3>174.&nbsp;Typo: <tt>OFF_T</tt> vs. <tt>POS_T</tt>
</h3></a><p><b>Section:</b>&nbsp;D.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.ios.members"> [depr.ios.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;23 Jul 1999</p>
<p>According to paragraph 1 of this section, <tt>streampos</tt> is the
type <tt>OFF_T</tt>, the same type as <tt>streamoff</tt>. However, in
paragraph 6 the <tt>streampos</tt> gets the type <tt>POS_T</tt></p>
<p><b>Proposed resolution:</b></p>
<p>Change D.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.ios.members"> [depr.ios.members]</a> paragraph 1 from "<tt>typedef
OFF_T streampos;</tt>" to "<tt>typedef POS_T
streampos;</tt>"</p>
<hr>
<a name="175"><h3>175.&nbsp;Ambiguity for <tt>basic_streambuf::pubseekpos()</tt> and a few other functions.</h3></a><p><b>Section:</b>&nbsp;D.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.ios.members"> [depr.ios.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;23 Jul 1999</p>
<p>According to paragraph 8 of this section, the methods
<tt>basic_streambuf::pubseekpos()</tt>,
<tt>basic_ifstream::open()</tt>, and <tt>basic_ofstream::open</tt>
"may" be overloaded by a version of this function taking the
type <tt>ios_base::open_mode</tt> as last argument argument instead of
<tt>ios_base::openmode</tt> (<tt>ios_base::open_mode</tt> is defined
in this section to be an alias for one of the integral types). The
clause specifies, that the last argument has a default argument in
three cases.  However, this generates an ambiguity with the overloaded
version because now the arguments are absolutely identical if the last
argument is not specified.</p>
<p><b>Proposed resolution:</b></p>
<p>In D.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.ios.members"> [depr.ios.members]</a> paragraph 8, remove the default arguments for
<tt>basic_streambuf::pubseekpos()</tt>,
<tt>basic_ifstream::open()</tt>, and
<tt>basic_ofstream::open().</tt></p>
<hr>
<a name="176"><h3>176.&nbsp;<tt>exceptions()</tt> in <tt>ios_base</tt>...?</h3></a><p><b>Section:</b>&nbsp;D.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.ios.members"> [depr.ios.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;23 Jul 1999</p>
<p>The "overload" for the function <tt>exceptions()</tt> in
paragraph 8 gives the impression that there is another function of
this function defined in class <tt>ios_base</tt>. However, this is not
the case. Thus, it is hard to tell how the semantics (paragraph 9) can
be implemented: "Call the corresponding member function specified
in clause 27 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.input.output"> [lib.input.output]</a>."</p>
<p><b>Proposed resolution:</b></p>
<p>In D.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.ios.members"> [depr.ios.members]</a> paragraph 8, move the declaration of the
function <tt>exceptions()</tt>into class <tt>basic_ios</tt>.</p>
<hr>
<a name="179"><h3>179.&nbsp;Comparison of const_iterators to iterators doesn't work</h3></a><p><b>Section:</b>&nbsp;23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;2 Jul 1998</p>
<p>Currently the following will not compile on two well-known standard
library implementations:</p>

<blockquote>
  <pre>#include &lt;set&gt;
using namespace std;

void f(const set&lt;int&gt; &amp;s)
{
  set&lt;int&gt;::iterator i;
  if (i==s.end()); // s.end() returns a const_iterator
}</pre>
</blockquote>

<p>
The reason this doesn't compile is because operator== was implemented
as a member function of the nested classes set:iterator and
set::const_iterator, and there is no conversion from const_iterator to
iterator. Surprisingly, (s.end() == i) does work, though, because of
the conversion from iterator to const_iterator.
</p>

<p>
I don't see a requirement anywhere in the standard that this must
work. Should there be one?  If so, I think the requirement would need
to be added to the tables in section 24.1.1. I'm not sure about the
wording.  If this requirement existed in the standard, I would think
that implementors would have to make the comparison operators
non-member functions.</p>

<p>This issues was also raised on comp.std.c++ by Darin
Adler.&nbsp; The example given was:</p>

<blockquote>
  <pre>bool check_equal(std::deque&lt;int&gt;::iterator i,
std::deque&lt;int&gt;::const_iterator ci)
{
return i == ci;
}</pre>
</blockquote>

<p>Comment from John Potter:</p>
<blockquote>
    <p>
    In case nobody has noticed, accepting it will break reverse_iterator.
    </p>

    <p>
    The fix is to make the comparison operators templated on two types.
    </p>

    <pre>    template &lt;class Iterator1, class Iterator2&gt;
    bool operator== (reverse_iterator&lt;Iterator1&gt; const&amp; x,
                     reverse_iterator&lt;Iterator2&gt; const&amp; y);
    </pre>

    <p>
    Obviously:  return x.base() == y.base();
    </p>

    <p>
    Currently, no reverse_iterator to const_reverse_iterator compares are
    valid.
    </p>

    <p>
    BTW, I think the issue is in support of bad code.  Compares should be
    between two iterators of the same type.  All std::algorithms require
    the begin and end iterators to be of the same type. 
    </p>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Insert this paragraph after 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> paragraph 7:</p>
<blockquote>
  <p>In the expressions</p>
  <pre>    i == j
    i != j
    i &lt; j
    i &lt;= j
    i &gt;= j
    i &gt; j
    i - j
  </pre>
  <p>Where i and j denote objects of a container's iterator type,
  either or both may be replaced by an object of the container's
  const_iterator type referring to the same element with no
  change in semantics.</p>
</blockquote>

<p><i>[post-Toronto: Judy supplied a proposed resolution saying that
<tt>iterator</tt> and <tt>const_iterator</tt> could be freely mixed in
iterator comparison and difference operations.]</i></p>

<p><i>[Redmond: Dave and Howard supplied a new proposed resolution which
explicitly listed expressions; there was concern that the previous
proposed resolution was too informal.]</i></p>
<p><b>Rationale:</b></p>
<p>
The LWG believes it is clear that the above wording applies only to
the nested types <tt>X::iterator</tt> and <tt>X::const_iterator</tt>,
where <tt>X</tt> is a container.  There is no requirement that
<tt>X::reverse_iterator</tt> and <tt>X::const_reverse_iterator</tt>
can be mixed.  If mixing them is considered important, that's a
separate issue.  (Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#280">280</a>.)
</p>
<hr>
<a name="181"><h3>181.&nbsp;make_pair() unintended behavior</h3></a><p><b>Section:</b>&nbsp;20.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.pairs"> [lib.pairs]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;3 Aug 1999</p>
<p>The claim has surfaced in Usenet that expressions such as<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <tt>make_pair("abc", 3)</tt><br>
<br>
are illegal, notwithstanding their use in examples, because template instantiation tries to bind the first template
parameter to <tt> const char (&amp;)[4]</tt>, which type is uncopyable.<br>
<br>
I doubt anyone intended that behavior...
</p>
<p><b>Proposed resolution:</b></p>
<p>In 20.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.utility"> [lib.utility]</a>, paragraph 1 change the following
declaration of make_pair():</p>
<blockquote>
  <pre>template &lt;class T1, class T2&gt; pair&lt;T1,T2&gt; make_pair(const T1&amp;, const T2&amp;);</pre>
</blockquote>
<p>to:</p>
<blockquote>
  <pre>template &lt;class T1, class T2&gt; pair&lt;T1,T2&gt; make_pair(T1, T2);</pre>
</blockquote>
<p>  In 20.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.pairs"> [lib.pairs]</a> paragraph 7 and the line before, change:</p>
<blockquote>
<pre>template &lt;class T1, class T2&gt;
pair&lt;T1, T2&gt; make_pair(const T1&amp; x, const T2&amp; y);</pre>
</blockquote>
<p>to:</p>
<blockquote>
<pre>template &lt;class T1, class T2&gt;
pair&lt;T1, T2&gt; make_pair(T1 x, T2 y);</pre>
</blockquote>
<p>and add the following footnote to the effects clause:</p>
<blockquote>
  <p> According to 12.8 [class.copy], an implementation is permitted
  to not perform a copy of an argument, thus avoiding unnecessary
  copies.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>Two potential fixes were suggested by Matt Austern and Dietmar
Kühl, respectively, 1) overloading with array arguments, and 2) use of
a reference_traits class with a specialization for arrays.  Andy
Koenig suggested changing to pass by value. In discussion, it appeared
that this was a much smaller change to the standard that the other two
suggestions, and any efficiency concerns were more than offset by the
advantages of the solution. Two implementors reported that the
proposed resolution passed their test suites.</p>
<hr>
<a name="182"><h3>182.&nbsp;Ambiguous references to size_t</h3></a><p><b>Section:</b>&nbsp;17 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.library"> [lib.library]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Al Stevens&nbsp; <b>Date:</b>&nbsp;15 Aug 1999</p>
<p>Many references to <tt> size_t</tt> throughout the document
omit the <tt> std::</tt> namespace qualification.</p> <p>For
example, 17.4.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.replacement.functions"> [lib.replacement.functions]</a> paragraph 2:</p>
<blockquote>
<pre>&#8212; operator new(size_t)
&#8212; operator new(size_t, const std::nothrow_t&amp;)
&#8212; operator new[](size_t)
&#8212; operator new[](size_t, const std::nothrow_t&amp;)</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>   In 17.4.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.replacement.functions"> [lib.replacement.functions]</a> paragraph 2: replace:</p>
<blockquote>
<p><tt>     - operator new(size_t)<br>
     - operator new(size_t, const std::nothrow_t&amp;)<br>
     - operator new[](size_t)<br>
     - operator new[](size_t, const std::nothrow_t&amp;)</tt></p>
</blockquote>
<p>    by:</p>
<blockquote>
<pre>- operator new(std::size_t)
- operator new(std::size_t, const std::nothrow_t&amp;)
- operator new[](std::size_t)
- operator new[](std::size_t, const std::nothrow_t&amp;)</pre>
</blockquote>
<p>In [lib.allocator.requirements] 20.1.5, paragraph 4: replace:</p>
<blockquote>
  <p>The typedef members pointer, const_pointer, size_type, and difference_type
  are required to be T*, T const*, size_t, and ptrdiff_t, respectively.</p>
</blockquote>
<p>&nbsp;by:</p>
<blockquote>
  <p>The typedef members pointer, const_pointer, size_type, and difference_type
  are required to be T*, T const*, std::size_t, and std::ptrdiff_t,
  respectively.</p>
</blockquote>
<p>In [lib.allocator.members] 20.4.1.1, paragraphs 3 and 6: replace:</p>
<blockquote>
  <p>3 Notes: Uses ::operator new(size_t) (18.4.1).</p>
  <p>6 Note: the storage is obtained by calling ::operator new(size_t), but it
  is unspecified when or how often this function is called. The use of hint is
  unspecified, but intended as an aid to locality if an implementation so
  desires.</p>
</blockquote>
<p>by:</p>
<blockquote>
  <p>3 Notes: Uses ::operator new(std::size_t) (18.4.1).</p>
  <p>6 Note: the storage is obtained by calling ::operator new(std::size_t), but
  it is unspecified when or how often this function is called. The use of hint
  is unspecified, but intended as an aid to locality if an implementation so
  desires.</p>
</blockquote>
<p>In [lib.char.traits.require] 21.1.1, paragraph 1: replace:</p>
<blockquote>
  <p>In Table 37, X denotes a Traits class defining types and functions for the
  character container type CharT; c and d denote values of type CharT; p and q
  denote values of type const CharT*; s denotes a value of type CharT*; n, i and
  j denote values of type size_t; e and f denote values of type X::int_type; pos
  denotes a value of type X::pos_type; and state denotes a value of type X::state_type.</p>
</blockquote>
<p>by:</p>
<blockquote>
  <p>In Table 37, X denotes a Traits class defining types and functions for the
  character container type CharT; c and d denote values of type CharT; p and q
  denote values of type const CharT*; s denotes a value of type CharT*; n, i and
  j denote values of type std::size_t; e and f denote values of type X::int_type;
  pos denotes a value of type X::pos_type; and state denotes a value of type X::state_type.</p>
</blockquote>
<p>In [lib.char.traits.require] 21.1.1, table 37: replace the return type of
X::length(p): "size_t" by "std::size_t".</p>
<p>   In [lib.std.iterator.tags] 24.3.3, paragraph 2:    replace:<br>
&nbsp;&nbsp;&nbsp; typedef ptrdiff_t difference_type;<br>
    by:<br>
&nbsp;&nbsp;&nbsp; typedef std::ptrdiff_t difference_type;</p>
<p> In [lib.locale.ctype] 22.2.1.1 put namespace std { ...} around the
declaration of template &lt;class charT&gt; class ctype.<br>
<br>
   In [lib.iterator.traits] 24.3.1, paragraph 2    put namespace std { ...} around the declaration of:<br>
<br>
&nbsp;&nbsp;&nbsp; template&lt;class Iterator&gt; struct iterator_traits<br>
&nbsp;&nbsp;&nbsp; template&lt;class T&gt; struct iterator_traits&lt;T*&gt;<br>
&nbsp;&nbsp;&nbsp; template&lt;class T&gt; struct iterator_traits&lt;const T*&gt;</p>
<p><b>Rationale:</b></p>
<p>The LWG believes correcting names like <tt>size_t</tt> and
<tt>ptrdiff_t</tt> to <tt>std::size_t</tt> and <tt>std::ptrdiff_t</tt>
to be essentially editorial.  There there can't be another size_t or
ptrdiff_t meant anyway because, according to 17.4.3.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.extern.types"> [lib.extern.types]</a>,</p>

<blockquote>
For each type T from the Standard C library, the types ::T and std::T
are reserved to the implementation and, when defined, ::T shall be
identical to std::T.
</blockquote>

<p>The issue is treated as a Defect Report to make explicit the Project
Editor's authority to make this change.</p>

<p><i>[Post-Tokyo: Nico Josuttis provided the above wording at the
request of the LWG.]</i></p>

<p><i>[Toronto: This is tangentially related to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a>, but only tangentially: the intent of this issue is to
address use of the name <tt>size_t</tt> in contexts outside of
namespace std, such as in the description of <tt>::operator new</tt>.
The proposed changes should be reviewed to make sure they are
correct.]</i></p>

<p><i>[pre-Copenhagen: Nico has reviewed the changes and believes
them to be correct.]</i></p>

<hr>
<a name="183"><h3>183.&nbsp;I/O stream manipulators don't work for wide character streams</h3></a><p><b>Section:</b>&nbsp;27.6.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.std.manip"> [lib.std.manip]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andy Sawyer&nbsp; <b>Date:</b>&nbsp;7 Jul 1999</p>
<p>27.6.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.std.manip"> [lib.std.manip]</a> paragraph 3 says (clause numbering added for
exposition):</p>
<blockquote>
<p>Returns: An object s of unspecified type such that if [1] out is an (instance
of) basic_ostream then the expression out&lt;&lt;s behaves as if f(s) were
called, and if [2] in is an (instance of) basic_istream then the expression
in&gt;&gt;s behaves as if f(s) were called. Where f can be defined as: ios_base&amp;
f(ios_base&amp; str, ios_base::fmtflags mask) { // reset specified flags
str.setf(ios_base::fmtflags(0), mask); return str; } [3] The expression
out&lt;&lt;s has type ostream&amp; and value out. [4] The expression in&gt;&gt;s
has type istream&amp; and value in.</p>
</blockquote>
<p>Given the definitions [1] and [2] for out and in, surely [3] should read:
"The expression out &lt;&lt; s has type basic_ostream&amp; ..." and
[4] should read: "The expression in &gt;&gt; s has type basic_istream&amp;
..."</p>
<p>If the wording in the standard is correct, I can see no way of implementing
any of the manipulators so that they will work with wide character streams.</p>
<p>e.g. wcout &lt;&lt; setbase( 16 );</p>
<p>Must have value 'wcout' (which makes sense) and type 'ostream&amp;' (which
doesn't).</p>
<p>The same "cut'n'paste" type also seems to occur in Paras 4,5,7 and
8. In addition, Para 6 [setfill] has a similar error, but relates only to
ostreams.</p>
<p>I'd be happier if there was a better way of saying this, to make it clear
that the value of the expression is "the same specialization of
basic_ostream as out"&amp;</p>
<p><b>Proposed resolution:</b></p>
<p>Replace section 27.6.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.std.manip"> [lib.std.manip]</a> except paragraph 1 with the
following:</p>
<blockquote>
<p>2- The type designated smanip in each of the following function
descriptions is implementation-specified and may be different for each
function.<br>
<br>
<tt>smanip resetiosflags(ios_base::fmtflags mask);</tt><br>
<br>
-3- Returns: An object s of unspecified type such that if out is an
instance of basic_ostream&lt;charT,traits&gt; then the expression
out&lt;&lt;s behaves
as if f(s, mask) were called, or if in is an instance of
basic_istream&lt;charT,traits&gt; then the expression in&gt;&gt;s
behaves as if
f(s, mask) were called. The function f can be defined as:*<br>
<br>
[Footnote: The expression cin &gt;&gt; resetiosflags(ios_base::skipws)
clears ios_base::skipws in the format flags stored in the
basic_istream&lt;charT,traits&gt; object cin (the same as cin &gt;&gt;
noskipws), and the expression cout &lt;&lt;
resetiosflags(ios_base::showbase) clears
ios_base::showbase in the format flags stored in the
basic_ostream&lt;charT,traits&gt; object cout (the same as cout
&lt;&lt;
noshowbase). --- end footnote]<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp; <tt>ios_base&amp; f(ios_base&amp; str, ios_base::fmtflags mask)<br>
&nbsp;&nbsp; {<br>
&nbsp;&nbsp; //  reset specified flags<br>
&nbsp;&nbsp; str.setf(ios_base::fmtflags(0), mask);<br>
&nbsp;&nbsp; return str;<br>
&nbsp;&nbsp; }<br>
</tt><br>
The expression out&lt;&lt;s has type basic_ostream&lt;charT,traits&gt;&amp; and value out.
The expression in&gt;&gt;s has type basic_istream&lt;charT,traits&gt;&amp; and value in.<br>
<br>
&nbsp;<tt>smanip setiosflags(ios_base::fmtflags mask);</tt><br>
<br>
-4- Returns: An object s of unspecified type such that if out is an
instance of basic_ostream&lt;charT,traits&gt; then the expression
out&lt;&lt;s behaves
as if f(s, mask) were called, or if in is an instance of
basic_istream&lt;charT,traits&gt; then the expression in&gt;&gt;s
behaves as if f(s,
mask) were called. The function f can be defined as:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp; <tt>ios_base&amp; f(ios_base&amp; str, ios_base::fmtflags mask)<br>
&nbsp;&nbsp; {<br>
&nbsp;&nbsp; //  set specified flags<br>
&nbsp;&nbsp; str.setf(mask);<br>
&nbsp;&nbsp; return str;<br>
&nbsp;&nbsp; }<br>
</tt><br>
The expression out&lt;&lt;s has type basic_ostream&lt;charT,traits&gt;&amp; and value out.
The expression in&gt;&gt;s has type basic_istream&lt;charT,traits&gt;&amp; and value in.<br>
<br>
<tt>smanip setbase(int base);</tt><br>
<br>
-5- Returns: An object s of unspecified type such that if out is an
instance of basic_ostream&lt;charT,traits&gt; then the expression
out&lt;&lt;s behaves
as if f(s, base) were called, or if in is an instance of
basic_istream&lt;charT,traits&gt; then the expression in&gt;&gt;s
behaves as if f(s,
base) were called. The function f can be defined as:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp; <tt>ios_base&amp; f(ios_base&amp; str, int base)<br>
&nbsp;&nbsp; {<br>
&nbsp;&nbsp; //  set  basefield<br>
&nbsp;&nbsp; str.setf(base ==  8 ? ios_base::oct :<br>
&nbsp;&nbsp; base == 10 ? ios_base::dec :<br>
&nbsp;&nbsp; base == 16 ? ios_base::hex :<br>
&nbsp;&nbsp; ios_base::fmtflags(0), ios_base::basefield);<br>
&nbsp;&nbsp; return str;<br>
&nbsp;&nbsp; }<br>
</tt><br>
The expression out&lt;&lt;s has type basic_ostream&lt;charT,traits&gt;&amp; and value out.
The expression in&gt;&gt;s has type basic_istream&lt;charT,traits&gt;&amp; and value in.<br>
<br>
<tt>smanip setfill(char_type c);<br>
</tt><br>
-6- Returns: An object s of unspecified type such that if out is (or is
derived from) basic_ostream&lt;charT,traits&gt; and c has type charT
then the
expression out&lt;&lt;s behaves as if f(s, c) were called. The function
f can be
defined as:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <tt>template&lt;class charT, class traits&gt;<br>
&nbsp;&nbsp; basic_ios&lt;charT,traits&gt;&amp; f(basic_ios&lt;charT,traits&gt;&amp; str, charT c)<br>
&nbsp;&nbsp; {<br>
&nbsp;&nbsp; //  set fill character<br>
&nbsp;&nbsp; str.fill(c);<br>
&nbsp;&nbsp; return str;<br>
&nbsp;&nbsp; }<br>
</tt><br>
The expression out&lt;&lt;s has type basic_ostream&lt;charT,traits&gt;&amp; and value out.<br>
<br>
<tt>smanip setprecision(int n);</tt><br>
<br>
-7- Returns: An object s of unspecified type such that if out is an
instance of basic_ostream&lt;charT,traits&gt; then the expression
out&lt;&lt;s behaves
as if f(s, n) were called, or if in is an instance of
basic_istream&lt;charT,traits&gt; then the expression in&gt;&gt;s
behaves as if f(s, n)
were called. The function f can be defined as:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <tt>ios_base&amp; f(ios_base&amp; str, int n)<br>
&nbsp;&nbsp; {<br>
&nbsp;&nbsp; //  set precision<br>
&nbsp;&nbsp; str.precision(n);<br>
&nbsp;&nbsp; return str;<br>
&nbsp;&nbsp; }<br>
</tt><br>
The expression out&lt;&lt;s has type basic_ostream&lt;charT,traits&gt;&amp; and value out.
The expression in&gt;&gt;s has type basic_istream&lt;charT,traits&gt;&amp; and value in<br>
.<br>
<tt>smanip setw(int n);<br>
</tt><br>
-8- Returns: An object s of unspecified type such that if out is an
instance of basic_ostream&lt;charT,traits&gt; then the expression
out&lt;&lt;s behaves
as if f(s, n) were called, or if in is an instance of
basic_istream&lt;charT,traits&gt; then the expression in&gt;&gt;s
behaves as if f(s, n)
were called. The function f can be defined as:<br>
<br>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <tt>ios_base&amp; f(ios_base&amp; str, int n)<br>
&nbsp;&nbsp; {<br>
&nbsp;&nbsp; //  set width<br>
&nbsp;&nbsp; str.width(n);<br>
&nbsp;&nbsp; return str;<br>
&nbsp;&nbsp; }<br>
</tt><br>
The expression out&lt;&lt;s has type
basic_ostream&lt;charT,traits&gt;&amp; and value out.  The expression
in&gt;&gt;s has type basic_istream&lt;charT,traits&gt;&amp; and value
in.
</p>
</blockquote>

<p><i>[Kona: Andy Sawyer and Beman Dawes will work to improve the wording of
the proposed resolution.]</i></p>

<p><i>[Tokyo - The LWG noted that issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#216">216</a> involves
the same paragraphs.]</i></p>

<p><i>[Post-Tokyo: The issues list maintainer combined the proposed
resolution of this issue with the proposed resolution for issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#216">216</a> as they both involved the same paragraphs, and were so
intertwined that dealing with them separately appear fraught with
error.  The full text was supplied by Bill Plauger; it was cross
checked against changes supplied by Andy Sawyer. It should be further
checked by the LWG.]</i></p>
<hr>
<a name="184"><h3>184.&nbsp;numeric_limits&lt;bool&gt; wording problems</h3></a><p><b>Section:</b>&nbsp;18.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.numeric.special"> [lib.numeric.special]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Gabriel Dos Reis&nbsp; <b>Date:</b>&nbsp;21 Jul 1999</p>
<p>bools are defined by the standard to be of integer types, as per
3.9.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/basic.html#basic.fundamental"> [basic.fundamental]</a> paragraph 7.  However "integer types"
seems to have a special meaning for the author of 18.2. The net effect
is an unclear and confusing specification for
numeric_limits&lt;bool&gt; as evidenced below.</p>

<p>18.2.1.2/7 says numeric_limits&lt;&gt;::digits is, for built-in integer
types, the number of non-sign bits in the representation.</p>

<p>4.5/4 states that a bool promotes to int ; whereas 4.12/1 says any non zero
arithmetical value converts to true.</p>

<p>I don't think it makes sense at all to require
numeric_limits&lt;bool&gt;::digits and numeric_limits&lt;bool&gt;::digits10 to
be meaningful.</p>

<p>The standard defines what constitutes a signed (resp. unsigned) integer
types. It doesn't categorize bool as being signed or unsigned. And the set of
values of bool type has only two elements.</p>

<p>I don't think it makes sense to require numeric_limits&lt;bool&gt;::is_signed
to be meaningful.</p>

<p>18.2.1.2/18 for numeric_limits&lt;integer_type&gt;::radix&nbsp; says:</p>
<blockquote>
  <p>For integer types, specifies the base of the representation.186)</p>
</blockquote>

<p>This disposition is at best misleading and confusing for the standard
requires a "pure binary numeration system" for integer types as per
3.9.1/7</p>

<p>The footnote 186) says: "Distinguishes types with base other than 2 (e.g
BCD)."&nbsp; This also erroneous as the standard never defines any integer
types with base representation other than 2.</p>

<p>Furthermore, numeric_limits&lt;bool&gt;::is_modulo and
numeric_limits&lt;bool&gt;::is_signed have similar problems.</p>
<p><b>Proposed resolution:</b></p>
<p>Append to the end of 18.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.numeric.special"> [lib.numeric.special]</a>:</p>
<blockquote>
  <p>The specialization for bool shall be provided as follows:</p>
  <pre>    namespace std {
       template&lt;&gt; class numeric_limits&lt;bool&gt; {
       public:
         static const bool is_specialized = true;
         static bool min() throw() { return false; }
         static bool max() throw() { return true; }

         static const int  digits = 1;
         static const int  digits10 = 0;
         static const bool is_signed = false;
         static const bool is_integer = true;
         static const bool is_exact = true;
         static const int  radix = 2;
         static bool epsilon() throw() { return 0; }
         static bool round_error() throw() { return 0; }

         static const int  min_exponent = 0;
         static const int  min_exponent10 = 0;
         static const int  max_exponent = 0;
         static const int  max_exponent10 = 0;

         static const bool has_infinity = false;
         static const bool has_quiet_NaN = false;
         static const bool has_signaling_NaN = false;
         static const float_denorm_style has_denorm = denorm_absent;
         static const bool has_denorm_loss = false;
         static bool infinity() throw() { return 0; }
         static bool quiet_NaN() throw() { return 0; }
         static bool signaling_NaN() throw() { return 0; }
         static bool denorm_min() throw() { return 0; }

         static const bool is_iec559 = false;
         static const bool is_bounded = true;
         static const bool is_modulo = false;

         static const bool traps = false;
         static const bool tinyness_before = false;
         static const float_round_style round_style = round_toward_zero;
       };
     }</pre>
</blockquote>

<p><i>[Tokyo:&nbsp; The LWG desires wording that specifies exact values
rather than more general wording in the original proposed
resolution.]</i></p>

<p><i>[Post-Tokyo:&nbsp; At the request of the LWG in Tokyo, Nico
Josuttis provided the above wording.]</i></p>
<hr>
<a name="185"><h3>185.&nbsp;Questionable use of term "inline"</h3></a><p><b>Section:</b>&nbsp;20.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple"> [lib.tuple]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;UK Panel&nbsp; <b>Date:</b>&nbsp;26 Jul 1999</p>
<p>Paragraph 4 of 20.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple"> [lib.tuple]</a> says:</p>
<blockquote>
  <p>&nbsp;[Example: To negate every element of a: transform(a.begin(), a.end(),
  a.begin(), negate&lt;double&gt;()); The corresponding functions will inline
  the addition and the negation. end example]</p>
</blockquote>
<p>(Note: The "addition" referred to in the above is in para 3) we can
find no other wording, except this (non-normative) example which suggests that
any "inlining" will take place in this case.</p>
<p>Indeed both:</p>
<blockquote>
  <p>17.4.4.3 Global Functions [lib.global.functions] 1 It is
  unspecified whether any global functions in the C++ Standard Library
  are defined as inline (7.1.2).</p>
</blockquote>
<p>and</p>
<blockquote>
  <p>17.4.4.4 Member Functions [lib.member.functions] 1 It is
  unspecified whether any member functions in the C++ Standard Library
  are defined as inline (7.1.2).</p>
</blockquote>
<p>take care to state that this may indeed NOT be the case.</p>
<p>Thus the example "mandates" behavior that is explicitly
not required elsewhere.</p>
<p><b>Proposed resolution:</b></p>
<p>In 20.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple"> [lib.tuple]</a> paragraph 1, remove the sentence:</p>
<blockquote>
<p>They are important for the effective use of the library.</p>
</blockquote>
<p>Remove 20.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple"> [lib.tuple]</a> paragraph 2, which reads:</p>
<blockquote>
  <p> Using function objects together with function templates
  increases the expressive power of the library as well as making the
  resulting code much more efficient.</p>
</blockquote>
<p>In 20.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.tuple"> [lib.tuple]</a> paragraph 4, remove the sentence:</p>
<blockquote>
  <p>The corresponding functions will inline the addition and the
  negation.</p>
</blockquote>

<p><i>[Kona: The LWG agreed there was a defect.]</i></p>
<p><i>[Tokyo: The LWG crafted the proposed resolution.]</i></p>
<hr>
<a name="186"><h3>186.&nbsp;bitset::set() second parameter should be bool</h3></a><p><b>Section:</b>&nbsp;23.3.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.members"> [lib.bitset.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Darin Adler&nbsp; <b>Date:</b>&nbsp;13 Aug 1999</p>
<p>In section 23.3.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.members"> [lib.bitset.members]</a>, paragraph 13 defines the
bitset::set operation to take a second parameter of type int. The
function tests whether this value is non-zero to determine whether to
set the bit to true or false. The type of this second parameter should
be bool. For one thing, the intent is to specify a Boolean value. For
another, the result type from test() is bool. In addition, it's
possible to slice an integer that's larger than an int. This can't
happen with bool, since conversion to bool has the semantic of
translating 0 to false and any non-zero value to true.</p>
<p><b>Proposed resolution:</b></p>
<p>In 23.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.template.bitset"> [lib.template.bitset]</a> Para 1 Replace:</p>
<blockquote>
<pre>bitset&lt;N&gt;&amp; set(size_t pos, int val = true ); </pre>
</blockquote>
<p>With:</p>
<blockquote>
  <pre>bitset&lt;N&gt;&amp; set(size_t pos, bool val = true );</pre>
</blockquote>
<p>In 23.3.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.members"> [lib.bitset.members]</a> Para 12(.5) Replace:</p>
<blockquote>
  <pre>bitset&lt;N&gt;&amp; set(size_t pos, int val = 1 );</pre>
</blockquote>
<p>With:</p>
<blockquote>
  <pre>bitset&lt;N&gt;&amp; set(size_t pos, bool val = true );</pre>
</blockquote>

<p><i>[Kona: The LWG agrees with the description.&nbsp; Andy Sawyer will work
on better P/R wording.]</i></p>
<p><i>[Post-Tokyo: Andy provided the above wording.]</i></p>
<p><b>Rationale:</b></p>
<p><tt>bool</tt> is a better choice.  It is believed that binary
compatibility is not an issue, because this member function is
usually implemented as <tt>inline</tt>, and because it is already
the case that users cannot rely on the type of a pointer to a
nonvirtual member of a standard library class.</p>
<hr>
<a name="187"><h3>187.&nbsp;iter_swap underspecified</h3></a><p><b>Section:</b>&nbsp;25.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.swap"> [lib.alg.swap]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;14 Aug 1999</p>
<p>The description of iter_swap in 25.2.2 paragraph 7,says that it
``exchanges the values'' of the objects to which two iterators
refer.<br> <br> What it doesn't say is whether it does so using swap
or using the assignment operator and copy constructor.<br> <br> This
question is an important one to answer, because swap is specialized to
work efficiently for standard containers.<br> For example:</p>
<blockquote>
<pre>vector&lt;int&gt; v1, v2;
iter_swap(&amp;v1, &amp;v2);</pre>
</blockquote>
<p>Is this call to iter_swap equivalent to calling swap(v1, v2)?&nbsp;
Or is it equivalent to</p>
<blockquote>
<pre>{
vector&lt;int&gt; temp = v1;
v1 = v2;
v2 = temp;
}</pre>
</blockquote>
<p>The first alternative is O(1); the second is O(n).</p>
<p>A LWG member, Dave Abrahams, comments:</p>
<blockquote>
<p>Not an objection necessarily, but I want to point out the cost of
that requirement:</p>
  <blockquote>
<p><tt>iter_swap(list&lt;T&gt;::iterator, list&lt;T&gt;::iterator)</tt></p>
  </blockquote>
<p>can currently be specialized to be more efficient than
iter_swap(T*,T*) for many T (by using splicing). Your proposal would
make that optimization illegal.&nbsp;</p>
</blockquote>

<p><i>[Kona: The LWG notes the original need for iter_swap was proxy iterators
which are no longer permitted.]</i></p>
<p><b>Proposed resolution:</b></p>
<p>Change the effect clause of iter_swap in 25.2.2 paragraph 7 from:</p>
<blockquote>
<p>Exchanges the values pointed to by the two iterators a and b.</p>
</blockquote>
<p>to</p>
<blockquote>
<p><tt>swap(*a, *b)</tt>.</p>
</blockquote>

<p><b>Rationale:</b></p>
<p>It's useful to say just what <tt>iter_swap</tt> does.  There may be
  some iterators for which we want to specialize <tt>iter_swap</tt>,
  but the fully general version should have a general specification.</p>

<p>Note that in the specific case of <tt>list&lt;T&gt;::iterator</tt>,
iter_swap should not be specialized as suggested above.  That would do
much more than exchanging the two iterators' values: it would change
predecessor/successor relationships, possibly moving the iterator from
one list to another.  That would surely be inappropriate.</p>
<hr>
<a name="189"><h3>189.&nbsp;setprecision() not specified correctly</h3></a><p><b>Section:</b>&nbsp;27.4.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fmtflags.state"> [lib.fmtflags.state]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;25 Aug 1999</p>
<p>27.4.2.2 paragraph 9 claims that setprecision() sets the precision,
and includes a parenthetical note saying that it is the number of
digits after the decimal point.<br>
<br>
This claim is not strictly correct.  For example, in the default
floating-point output format, setprecision sets the number of
significant digits printed, not the number of digits after the decimal
point.<br>
<br>
I would like the committee to look at the definition carefully and
correct the statement in 27.4.2.2</p>
<p><b>Proposed resolution:</b></p>
<p>Remove from 27.4.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fmtflags.state"> [lib.fmtflags.state]</a>, paragraph 9, the text
"(number of digits after the decimal point)".</p>
<hr>
<a name="193"><h3>193.&nbsp;Heap operations description incorrect</h3></a><p><b>Section:</b>&nbsp;25.3.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.heap.operations"> [lib.alg.heap.operations]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Markus Mauhart&nbsp; <b>Date:</b>&nbsp;24 Sep 1999</p>
<p>25.3.6 [lib.alg.heap.operations] states two key properties of a heap [a,b), the first of them
is<br>
<br>
&nbsp;&nbsp;&nbsp; `"(1) *a is the largest element"<br>
<br>
I think this is incorrect and should be changed to the wording in the proposed
resolution.</p>
<p>Actually there are two independent changes:</p>
<blockquote>
  <p>A-"part of largest equivalence class" instead of "largest", cause 25.3
  [lib.alg.sorting] asserts "strict weak ordering" for all its sub clauses.</p>
  <p>B-Take
'an oldest' from that equivalence class, otherwise the heap functions
could not be used for a priority queue as explained in 23.2.3.2.2
[lib.priqueue.members] (where I assume that a "priority queue" respects
priority AND time).</p>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Change 25.3.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.heap.operations"> [lib.alg.heap.operations]</a> property (1) from:</p>
<blockquote>
  <p>(1) *a is the largest element</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>(1) There is no element greater than <tt>*a</tt></p>
</blockquote>
<hr>
<a name="195"><h3>195.&nbsp;Should <tt>basic_istream::sentry</tt>'s constructor ever set eofbit?</h3></a><p><b>Section:</b>&nbsp;27.6.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::sentry"> [lib.istream::sentry]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;13 Oct 1999</p>
<p>Suppose that <tt>is.flags() &amp; ios_base::skipws</tt> is nonzero.
What should <tt>basic_istream&lt;&gt;::sentry</tt>'s constructor do if it
reaches eof while skipping whitespace?  27.6.1.1.2/5 suggests it
should set failbit. Should it set eofbit as well?  The standard
doesn't seem to answer that question.</p>

<p>On the one hand, nothing in 27.6.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::sentry"> [lib.istream::sentry]</a> says that
<tt>basic_istream&lt;&gt;::sentry</tt> should ever set eofbit.  On the
other hand, 27.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream"> [lib.istream]</a> paragraph 4 says that if
extraction from a <tt>streambuf</tt> "returns
<tt>traits::eof()</tt>, then the input function, except as explicitly
noted otherwise, completes its actions and does
<tt>setstate(eofbit)"</tt>.  So the question comes down to
whether <tt>basic_istream&lt;&gt;::sentry</tt>'s constructor is an
input function.</p>

<p>Comments from Jerry Schwarz:</p>
<blockquote>
<p>It was always my intention that eofbit should be set any time that a
virtual returned something to indicate eof, no matter what reason
iostream code had for calling the virtual.</p>
<p>
The motivation for this is that I did not want to require streambufs
to behave consistently if their virtuals are called after they have
signaled eof.</p>
<p>
The classic case is a streambuf reading from a UNIX file.  EOF isn't
really a state for UNIX file descriptors.  The convention is that a
read on UNIX returns 0 bytes to indicate "EOF", but the file
descriptor isn't shut down in any way and future reads do not
necessarily also return 0 bytes.  In particular, you can read from
tty's on UNIX even after they have signaled "EOF".  (It
isn't always understood that a ^D on UNIX is not an EOF indicator, but
an EOL indicator.  By typing a "line" consisting solely of
^D you cause a read to return 0 bytes, and by convention this is
interpreted as end of file.)</p>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Add a sentence to the end of 27.6.1.1.2 paragraph 2:</p>
<blockquote>
<p>If <tt>is.rdbuf()-&gt;sbumpc()</tt> or <tt>is.rdbuf()-&gt;sgetc()</tt>
returns <tt>traits::eof()</tt>, the function calls
<tt>setstate(failbit | eofbit)</tt> (which may throw
<tt>ios_base::failure</tt>).
</p>
</blockquote>
<hr>
<a name="198"><h3>198.&nbsp;Validity of pointers and references unspecified after iterator destruction</h3></a><p><b>Section:</b>&nbsp;24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;3 Nov 1999</p>
<p>
Is a pointer or reference obtained from an iterator still valid after
destruction of the iterator?
</p>
<p>
Is a pointer or reference obtained from an iterator still valid after the value
of the iterator changes?
</p>
<blockquote>
<pre>#include &lt;iostream&gt;
#include &lt;vector&gt;
#include &lt;iterator&gt;

int main()
{
    typedef std::vector&lt;int&gt; vec_t;
    vec_t v;
    v.push_back( 1 );

    // Is a pointer or reference obtained from an iterator still
    // valid after destruction of the iterator?
    int * p = &amp;*v.begin();
    std::cout &lt;&lt; *p &lt;&lt; '\n';  // OK?

    // Is a pointer or reference obtained from an iterator still
    // valid after the value of the iterator changes?
    vec_t::iterator iter( v.begin() );
    p = &amp;*iter++;
    std::cout &lt;&lt; *p &lt;&lt; '\n';  // OK?

    return 0;
}
</pre>
</blockquote>

<p>The standard doesn't appear to directly address these
questions. The standard needs to be clarified. At least two real-world
cases have been reported where library implementors wasted
considerable effort because of the lack of clarity in the
standard. The question is important because requiring pointers and
references to remain valid has the effect for practical purposes of
prohibiting iterators from pointing to cached rather than actual
elements of containers.</p>

<p>The standard itself assumes that pointers and references obtained
from an iterator are still valid after iterator destruction or
change. The definition of reverse_iterator::operator*(), 24.4.1.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.conv"> [lib.reverse.iter.conv]</a>, which returns a reference, defines
effects:</p>

<blockquote>
  <pre>Iterator tmp = current;
return *--tmp;</pre>
</blockquote>
<p>The definition of reverse_iterator::operator-&gt;(), 24.4.1.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.op.star"> [lib.reverse.iter.op.star]</a>, which returns a pointer, defines effects:</p>
<blockquote>
  <pre>return &amp;(operator*());</pre>
</blockquote>

<p>Because the standard itself assumes pointers and references remain
valid after iterator destruction or change, the standard should say so
explicitly. This will also reduce the chance of user code breaking
unexpectedly when porting to a different standard library
implementation.</p>
<p><b>Proposed resolution:</b></p>
<p>Add a new paragraph to 24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>:</p>
<blockquote>
Destruction of an iterator may invalidate pointers and references
previously obtained from that iterator.
</blockquote>

<p>Replace paragraph 1 of 24.4.1.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.conv"> [lib.reverse.iter.conv]</a> with:</p>

<blockquote>
<p><b>Effects:</b></p>
<pre>  this-&gt;tmp = current;
  --this-&gt;tmp;
  return *this-&gt;tmp;
</pre>

<p>
[<i>Note:</i> This operation must use an auxiliary member variable,
rather than a temporary variable, to avoid returning a reference that
persists beyond the lifetime of its associated iterator.  (See
24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>.)  The name of this member variable is shown for
exposition only.  <i>--end note</i>]
</p>
</blockquote>

<p><i>[Post-Tokyo: The issue has been reformulated purely
in terms of iterators.]</i></p>

<p><i>[Pre-Toronto: Steve Cleary pointed out the no-invalidation
assumption by reverse_iterator. The issue and proposed resolution was
reformulated yet again to reflect this reality.]</i></p>

<p><i>[Copenhagen: Steve Cleary pointed out that reverse_iterator
assumes its underlying iterator has persistent pointers and
references.  Andy Koenig pointed out that it is possible to rewrite
reverse_iterator so that it no longer makes such an assupmption.
However, this issue is related to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#299">299</a>.  If we
decide it is intentional that <tt>p[n]</tt> may return by value
instead of reference when <tt>p</tt> is a Random Access Iterator,
other changes in reverse_iterator will be necessary.]</i></p>
<p><b>Rationale:</b></p>
<p>This issue has been discussed extensively.  Note that it is
<i>not</i> an issue about the behavior of predefined iterators.  It is
asking whether or not user-defined iterators are permitted to have
transient pointers and references.  Several people presented examples
of useful user-defined iterators that have such a property; examples
include a B-tree iterator, and an "iota iterator" that doesn't point
to memory.  Library implementors already seem to be able to cope with
such iterators: they take pains to avoid forming references to memory
that gets iterated past.  The only place where this is a problem is
<tt>reverse_iterator</tt>, so this issue changes
<tt>reverse_iterator</tt> to make it work.</p>

<p>This resolution does not weaken any guarantees provided by
predefined iterators like <tt>list&lt;int&gt;::iterator</tt>.
Clause 23 should be reviewed to make sure that guarantees for
predefined iterators are as strong as users expect.</p>

<hr>
<a name="199"><h3>199.&nbsp;What does <tt>allocate(0)</tt> return?</h3></a><p><b>Section:</b>&nbsp;20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;19 Nov 1999</p>
<p>
Suppose that <tt>A</tt> is a class that conforms to the
Allocator requirements of Table 32, and <tt>a</tt> is an
object of class <tt>A</tt>  What should be the return
value of <tt>a.allocate(0)</tt>?  Three reasonable
possibilities: forbid the argument <tt>0</tt>, return
a null pointer, or require that the return value be a
unique non-null pointer.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add a note to the <tt>allocate</tt> row of Table 32:
"[<i>Note:</i> If <tt>n == 0</tt>, the return value is unspecified. <i>--end note</i>]"</p>
<p><b>Rationale:</b></p>
<p>A key to understanding this issue is that the ultimate use of
allocate() is to construct an iterator, and that iterator for zero
length sequences must be the container's past-the-end
representation.  Since this already implies special case code, it
would be over-specification to mandate the return value.
</p>
<hr>
<a name="200"><h3>200.&nbsp;Forward iterator requirements don't allow constant iterators</h3></a><p><b>Section:</b>&nbsp;24.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.forward.iterators"> [lib.forward.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;19 Nov 1999</p>
<p>
In table 74, the return type of the expression <tt>*a</tt> is given
as <tt>T&amp;</tt>, where <tt>T</tt> is the iterator's value type.
For constant iterators, however, this is wrong.  ("Value type"
is never defined very precisely, but it is clear that the value type
of, say, <tt>std::list&lt;int&gt;::const_iterator</tt> is supposed to be
<tt>int</tt>, not <tt>const int</tt>.)
</p>
<p><b>Proposed resolution:</b></p>
<p>
In table 74, in the <tt>*a</tt> and <tt>*r++</tt> rows, change the
return type from "<tt>T&amp;</tt>" to "<tt>T&amp;</tt>
if <tt>X</tt> is mutable, otherwise <tt>const T&amp;</tt>".
In the <tt>a-&gt;m</tt> row, change the return type from
"<tt>U&amp;</tt>" to "<tt>U&amp;</tt> if <tt>X</tt> is mutable,
otherwise <tt>const U&amp;</tt>".
</p>

<p><i>[Tokyo: The LWG believes this is the tip of a larger iceberg;
there are multiple const problems with the STL portion of the library
and that these should be addressed as a single package.&nbsp; Note
that issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#180">180</a> has already been declared NAD Future for
that very reason.]</i></p>

<p><i>[Redmond: the LWG thinks this is separable from other constness
issues.  This issue is just cleanup; it clarifies language that was
written before we had iterator_traits.  Proposed resolution was
modified: the original version only discussed *a.  It was pointed out
that we also need to worry about *r++ and a-&gt;m.]</i></p>

<hr>
<a name="202"><h3>202.&nbsp;unique() effects unclear when predicate not an equivalence relation</h3></a><p><b>Section:</b>&nbsp;25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Koenig&nbsp; <b>Date:</b>&nbsp;13 Jan 2000</p>
<p>
What should unique() do if you give it a predicate that is not an
equivalence relation?  There are at least two plausible answers:
</p>

<blockquote>

<p>
   1. You can't, because 25.2.8 says that it it "eliminates all but
   the first element from every consecutive group of equal
   elements..." and it wouldn't make sense to interpret "equal" as
   meaning anything but an equivalence relation.  [It also doesn't
   make sense to interpret "equal" as meaning ==, because then there
   would never be any sense in giving a predicate as an argument at
   all.]
</p>

<p>
   2. The word "equal" should be interpreted to mean whatever the
   predicate says, even if it is not an equivalence relation
   (and in particular, even if it is not transitive).
</p>

</blockquote>

<p>
The example that raised this question is from Usenet:
</p>

<blockquote>

<pre>int f[] = { 1, 3, 7, 1, 2 };
int* z = unique(f, f+5, greater&lt;int&gt;());</pre>

</blockquote>

<p>
If one blindly applies the definition using the predicate
greater&lt;int&gt;, and ignore the word "equal", you get:
</p>

<blockquote>

<p>
    Eliminates all but the first element from every consecutive group    
    of elements referred to by the iterator i in the range [first, last)    
    for which *i &gt; *(i - 1).
</p>

</blockquote>

<p>
The first surprise is the order of the comparison.  If we wanted to
allow for the predicate not being an equivalence relation, then we
should surely compare elements the other way: pred(*(i - 1), *i).  If
we do that, then the description would seem to say: "Break the
sequence into subsequences whose elements are in strictly increasing
order, and keep only the first element of each subsequence".  So the
result would be 1, 1, 2.  If we take the description at its word, it
would seem to call for strictly DEcreasing order, in which case the
result should be 1, 3, 7, 2.<br>
<br>
In fact, the SGI implementation of unique() does neither: It yields 1,
3, 7.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change 25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a> paragraph 1 to:</p>
<blockquote>
For a nonempty range, eliminates all but the first element from every
consecutive group of equivalent elements referred to by the iterator
<tt>i</tt> in the range [first+1, last) for which the following
conditions hold: <tt>*(i-1) == *i</tt> or <tt>pred(*(i-1), *i) !=
false</tt>.
</blockquote>

<p>
Also insert a new paragraph, paragraph 2a, that reads: "Requires: The
comparison function must be an equivalence relation."
</p>

<p><i>[Redmond: discussed arguments for and against requiring the
comparison function to be an equivalence relation.  Straw poll:
14-2-5.  First number is to require that it be an equivalence
relation, second number is to explicitly not require that it be an
equivalence relation, third number is people who believe they need
more time to consider the issue.  A separate issue: Andy Sawyer
pointed out that "i-1" is incorrect, since "i" can refer to the first
iterator in the range.  Matt provided wording to address this
problem.]</i></p>

<p><i>[Curaçao: The LWG changed "... the range (first,
last)..." to "...  the range [first+1, last)..." for
clarity. They considered this change close enough to editorial to not
require another round of review.]</i></p>

<p><b>Rationale:</b></p>
<p>The LWG also considered an alternative resolution: change 
25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a> paragraph 1 to:</p>

<blockquote>
For a nonempty range, eliminates all but the first element from every
consecutive group of elements referred to by the iterator
<tt>i</tt> in the range (first, last) for which the following
conditions hold: <tt>*(i-1) == *i</tt> or <tt>pred(*(i-1), *i) !=
false</tt>.
</blockquote>

<p>
Also insert a new paragraph, paragraph 1a, that reads: "Notes: The
comparison function need not be an equivalence relation."
</p>


<p>Informally: the proposed resolution imposes an explicit requirement
that the comparison function be an equivalence relation.  The
alternative resolution does not, and it gives enough information so
that the behavior of unique() for a non-equivalence relation is
specified.  Both resolutions are consistent with the behavior of
existing implementations.</p>
<hr>
<a name="208"><h3>208.&nbsp;Unnecessary restriction on past-the-end iterators</h3></a><p><b>Section:</b>&nbsp;24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Stephen Cleary&nbsp; <b>Date:</b>&nbsp;02 Feb 2000</p>
<p>In 24.1 paragraph 5, it is stated ". . . Dereferenceable and
past-the-end values are always non-singular."</p>
<p>This places an unnecessary restriction on past-the-end iterators for
containers with forward iterators (for example, a singly-linked list). If the
past-the-end value on such a container was a well-known singular value, it would
still satisfy all forward iterator requirements.</p>
<p>Removing this restriction would allow, for example, a singly-linked list
without a "footer" node.</p>
<p>This would have an impact on existing code that expects past-the-end
iterators obtained from different (generic) containers being not equal.</p>
<p><b>Proposed resolution:</b></p>
<p>Change 24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a> paragraph 5, the last sentence, from:</p>
<blockquote>
<p>Dereferenceable and past-the-end values are always non-singular.</p>
</blockquote>
<p>to:</p>
<blockquote>
<p>Dereferenceable values are always non-singular.&nbsp;</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>For some kinds of containers, including singly linked lists and
zero-length vectors, null pointers are perfectly reasonable past-the-end
iterators.  Null pointers are singular.
</p>
<hr>
<a name="209"><h3>209.&nbsp;basic_string declarations inconsistent</h3></a><p><b>Section:</b>&nbsp;21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Igor Stauder&nbsp; <b>Date:</b>&nbsp;11 Feb 2000</p>
<p>In Section 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a> the basic_string member function
declarations use a consistent style except for the following functions:</p>
<blockquote>
  <pre>void push_back(const charT);
basic_string&amp; assign(const basic_string&amp;);
void swap(basic_string&lt;charT,traits,Allocator&gt;&amp;);</pre>
</blockquote>
<p>- push_back, assign, swap: missing argument name&nbsp;<br>
- push_back: use of const with charT (i.e. POD type passed by value
not by reference - should be charT or const charT&amp; )<br>
- swap: redundant use of template parameters in argument
basic_string&lt;charT,traits,Allocator&gt;&amp;</p>
<p><b>Proposed resolution:</b></p>
<p>In Section 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a> change the basic_string member
function declarations push_back, assign, and swap to:</p>
<blockquote>
  <pre>void push_back(charT c); 

basic_string&amp; assign(const basic_string&amp; str);
void swap(basic_string&amp; str);</pre>
</blockquote>
<p><b>Rationale:</b></p>
<p>Although the standard is in general not consistent in declaration
style, the basic_string declarations are consistent other than the
above.  The LWG felt that this was sufficient reason to merit the
change.
</p>
<hr>
<a name="210"><h3>210.&nbsp;distance first and last confused</h3></a><p><b>Section:</b>&nbsp;25 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.algorithms"> [lib.algorithms]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Lisa Lippincott&nbsp; <b>Date:</b>&nbsp;15 Feb 2000</p>
<p>In paragraph 9 of section 25 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.algorithms"> [lib.algorithms]</a>, it is written:</p>
<blockquote>
  <p>      In the description of the algorithms operators + and - are used
           for some of the iterator categories for which they do not have to
           be defined. In these cases the semantics of [...] a-b is the same
           as of<br>
  <br>
  &nbsp;&nbsp;&nbsp;&nbsp; <tt>return distance(a, b);</tt></p>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>On the last line of paragraph 9 of section 25 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.algorithms"> [lib.algorithms]</a> change
<tt>"a-b"</tt> to <tt>"b-a".</tt></p>
<p><b>Rationale:</b></p>
<p>There are two ways to fix the defect; change the description to b-a
or change the return to distance(b,a).  The LWG preferred the
former for consistency.</p>
<hr>
<a name="211"><h3>211.&nbsp;operator&gt;&gt;(istream&amp;, string&amp;) doesn't set failbit</h3></a><p><b>Section:</b>&nbsp;21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Scott Snyder&nbsp; <b>Date:</b>&nbsp;4 Feb 2000</p>
<p>The description of the stream extraction operator for std::string (section
21.3.7.9 [lib.string.io]) does not contain a requirement that failbit be set in
the case that the operator fails to extract any characters from the input
stream.</p>
<p>This implies that the typical construction</p>
<blockquote>
  <pre>std::istream is;
std::string str;
...
while (is &gt;&gt; str) ... ;</pre>
</blockquote>
<p>(which tests failbit) is not required to terminate at EOF.</p>
<p>Furthermore, this is inconsistent with other extraction operators,
which do include this requirement. (See sections 27.6.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted"> [lib.istream.formatted]</a> and 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>), where this
requirement is present, either explicitly or implicitly, for the
extraction operators. It is also present explicitly in the description
of getline (istream&amp;, string&amp;, charT) in section 21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a> paragraph 8.)</p>
<p><b>Proposed resolution:</b></p>
<p>Insert new paragraph after paragraph 2 in section 21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>:</p>
<blockquote>

<p>If the function extracts no characters, it calls
is.setstate(ios::failbit) which may throw ios_base::failure
(27.4.4.3).</p>
</blockquote>
<hr>
<a name="212"><h3>212.&nbsp;Empty range behavior unclear for several algorithms</h3></a><p><b>Section:</b>&nbsp;25.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.min.max"> [lib.alg.min.max]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Nico Josuttis&nbsp; <b>Date:</b>&nbsp;26 Feb 2000</p>
<p>The standard doesn't specify what min_element() and max_element() shall
return if the range is empty (first equals last). The usual implementations
return last. This problem seems also apply to partition(), stable_partition(),
next_permutation(), and prev_permutation().</p>
<p><b>Proposed resolution:</b></p>
<p>In 25.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.min.max"> [lib.alg.min.max]</a> - Minimum and maximum, paragraphs 7 and
9, append: Returns last if first==last.</p>
<p><b>Rationale:</b></p>
<p>The LWG looked in some detail at all of the above mentioned
algorithms, but believes that except for min_element() and
max_element() it is already clear that last is returned if first ==
last.</p>
<hr>
<a name="214"><h3>214.&nbsp;set::find() missing const overload</h3></a><p><b>Section:</b>&nbsp;23.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.set"> [lib.set]</a>, 23.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.multiset"> [lib.multiset]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;28 Feb 2000</p>
<p>The specification for the associative container requirements in
Table 69 state that the find member function should "return
iterator; const_iterator for constant a". The map and multimap
container descriptions have two overloaded versions of find, but set
and multiset do not, all they have is:</p>
<blockquote>
  <pre>iterator find(const key_type &amp; x) const;</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Change the prototypes for find(), lower_bound(), upper_bound(), and
equal_range() in section 23.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.set"> [lib.set]</a> and section 23.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.multiset"> [lib.multiset]</a> to each have two overloads:</p>
<blockquote>
  <pre>iterator find(const key_type &amp; x);
const_iterator find(const key_type &amp; x) const;</pre>
  <pre>iterator lower_bound(const key_type &amp; x);
const_iterator lower_bound(const key_type &amp; x) const;</pre>
  <pre>iterator upper_bound(const key_type &amp; x);
const_iterator upper_bound(const key_type &amp; x) const;</pre>
  <pre>pair&lt;iterator, iterator&gt; equal_range(const key_type &amp; x);
pair&lt;const_iterator, const_iterator&gt; equal_range(const key_type &amp; x) const;</pre>
</blockquote>

<p><i>[Tokyo: At the request of the LWG, Judy Ward provided wording
extending the proposed resolution to lower_bound, upper_bound, and
equal_range.]</i></p>
<hr>
<a name="217"><h3>217.&nbsp;Facets example (Classifying Japanese characters) contains errors</h3></a><p><b>Section:</b>&nbsp;22.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facets.examples"> [lib.facets.examples]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;29 Feb 2000</p>
<p>The example in 22.2.8, paragraph 11 contains the following errors:</p>
<p>1) The member function `My::JCtype::is_kanji()' is non-const; the function
must be const in order for it to be callable on a const object (a reference to
which which is what std::use_facet&lt;&gt;() returns).</p>
<p>2) In file filt.C, the definition of `JCtype::id' must be qualified with the
name of the namespace `My'.</p>
<p>3) In the definition of `loc' and subsequently in the call to use_facet&lt;&gt;()
in main(), the name of the facet is misspelled: it should read `My::JCtype'
rather than `My::JCType'.</p>
<p><b>Proposed resolution:</b></p>
<p>Replace the "Classifying Japanese characters" example in 22.2.8,
paragraph 11 with the following:</p>
<pre>#include &lt;locale&gt;</pre>
<pre>namespace My {
    using namespace std;
    class JCtype : public locale::facet {
    public:
        static locale::id id;     //  required for use as a new locale facet
        bool is_kanji (wchar_t c) const;
        JCtype() {}
    protected:
        ~JCtype() {}
    };
}</pre>
<pre>//  file:  filt.C
#include &lt;iostream&gt;
#include &lt;locale&gt;
#include "jctype"                 //  above
std::locale::id My::JCtype::id;   //  the static  JCtype  member
declared above.</pre>
<pre>int main()
{
    using namespace std;
    typedef ctype&lt;wchar_t&gt; wctype;
    locale loc(locale(""),              //  the user's preferred locale...
               new My::JCtype);         //  and a new feature ...
    wchar_t c = use_facet&lt;wctype&gt;(loc).widen('!');
    if (!use_facet&lt;My::JCtype&gt;(loc).is_kanji(c))
        cout &lt;&lt; "no it isn't!" &lt;&lt; endl;
    return 0;
}</pre>
<hr>
<a name="220"><h3>220.&nbsp;~ios_base() usage valid?</h3></a><p><b>Section:</b>&nbsp;27.4.2.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios.base.cons"> [lib.ios.base.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Jonathan Schilling, Howard Hinnant&nbsp; <b>Date:</b>&nbsp;13 Mar 2000</p>
<p>The pre-conditions for the ios_base destructor are described in 27.4.2.7
paragraph 2:</p>
<blockquote>
  <p>Effects: Destroys an object of class ios_base. Calls each registered
  callback pair (fn,index) (27.4.2.6) as (*fn)(erase_event,*this,index) at such
  time that any ios_base member function called from within fn has well defined
  results.</p>
</blockquote>
<p>But what is not clear is: If no callback functions were ever registered, does
it matter whether the ios_base members were ever initialized?</p>
<p>For instance, does this program have defined behavior:</p>
<blockquote>
  <pre>#include &lt;ios&gt;</pre>
  <pre>class D : public std::ios_base { };</pre>
  <pre>int main() { D d; }</pre>
</blockquote>
<p>It seems that registration of a callback function would surely affect the
state of an ios_base. That is, when you register a callback function with an
ios_base, the ios_base must record that fact somehow.</p>
<p>But if after construction the ios_base is in an indeterminate state, and that
state is not made determinate before the destructor is called, then how would
the destructor know if any callbacks had indeed been registered? And if the
number of callbacks that had been registered is indeterminate, then is not the
behavior of the destructor undefined?</p>
<p>By comparison, the basic_ios class description in 27.4.4.1 paragraph 2 makes
it explicit that destruction before initialization results in undefined
behavior.</p>
<p><b>Proposed resolution:</b></p>
<p>Modify 27.4.2.7 paragraph 1 from</p>
<blockquote>
  <p>Effects: Each ios_base member has an indeterminate value after
  construction.</p>
</blockquote>
<p>to</p>
<blockquote>
  <p>Effects: Each ios_base member has an indeterminate
value after construction. These members must be initialized by calling
basic_ios::init. If an ios_base object is destroyed before these
initializations have taken place, the behavior is undefined.</p>
</blockquote>
<hr>
<a name="221"><h3>221.&nbsp;num_get&lt;&gt;::do_get stage 2 processing broken</h3></a><p><b>Section:</b>&nbsp;22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;14 Mar 2000</p>
<p>Stage 2 processing of numeric conversion is broken.</p>

<p>Table 55 in 22.2.2.1.2 says that when basefield is 0 the integral
conversion specifier is %i. A %i specifier determines a number's base
by its prefix (0 for octal, 0x for hex), so the intention is clearly
that a 0x prefix is allowed.  Paragraph 8 in the same section,
however, describes very precisely how characters are processed. (It
must be done "as if" by a specified code fragment.) That
description does not allow a 0x prefix to be recognized.</p>

<p>Very roughly, stage 2 processing reads a char_type ct. It converts
ct to a char, not by using narrow but by looking it up in a
translation table that was created by widening the string literal
"0123456789abcdefABCDEF+-". The character "x" is
not found in that table, so it can't be recognized by stage 2
processing.</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.2.1.2 paragraph 8, replace the line:</p>
<blockquote>
  <pre>static const char src[] = "0123456789abcdefABCDEF+-";</pre>
</blockquote>
<p>with the line:</p>
<blockquote>
  <pre>static const char src[] = "0123456789abcdefxABCDEFX+-";</pre>
</blockquote>
<p><b>Rationale:</b></p>
<p>If we're using the technique of widening a string literal, the
string literal must contain every character we wish to recognize.
This technique has the consequence that alternate representations
of digits will not be recognized.  This design decision was made
deliberately, with full knowledge of that limitation.</p>
<hr>
<a name="222"><h3>222.&nbsp;Are throw clauses necessary if a throw is already implied by the effects clause?</h3></a><p><b>Section:</b>&nbsp;17.3.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.structure.specifications"> [lib.structure.specifications]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;17 Mar 2000</p>
<p>Section 21.3.6.8 describes the basic_string::compare function this way:</p>
<blockquote>
  <pre>21.3.6.8 - basic_string::compare [lib.string::compare]

int compare(size_type pos1, size_type n1,
                const basic_string&lt;charT,traits,Allocator&gt;&amp;  str ,
                size_type  pos2 , size_type  n2 ) const;

-4- Returns: 

    basic_string&lt;charT,traits,Allocator&gt;(*this,pos1,n1).compare(
                 basic_string&lt;charT,traits,Allocator&gt;(str,pos2,n2)) .</pre>
</blockquote>
<p>and the constructor that's implicitly called by the above is
defined to throw an out-of-range exception if pos &gt; str.size(). See
section 21.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.cons"> [lib.string.cons]</a> paragraph 4.</p>

<p>On the other hand, the compare function descriptions themselves don't have
"Throws: " clauses and according to 17.3.1.3, paragraph 3, elements
that do not apply to a function are omitted.</p>
<p>So it seems there is an inconsistency in the standard -- are the
"Effects" clauses correct, or are the "Throws" clauses
missing?</p>
<p><b>Proposed resolution:</b></p>
<p>In 17.3.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.structure.specifications"> [lib.structure.specifications]</a> paragraph 3, the footnote 148 attached to
the sentence "Descriptions of function semantics contain the
following elements (as appropriate):", insert the word
"further" so that the foot note reads:</p>
<blockquote>
  <p>To save space, items that do not apply to a function are
  omitted. For example, if a function does not specify any further
  preconditions, there will be no "Requires" paragraph.</p>
</blockquote>
<p><b>Rationale:</b></p>
<p>The standard is somewhat inconsistent, but a failure to note a
throw condition in a throws clause does not grant permission not to
throw.  The inconsistent wording is in a footnote, and thus
non-normative. The proposed resolution from the LWG clarifies the
footnote.</p>
<hr>
<a name="223"><h3>223.&nbsp;reverse algorithm should use iter_swap rather than swap</h3></a><p><b>Section:</b>&nbsp;25.2.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.reverse"> [lib.alg.reverse]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;21 Mar 2000</p>
<p>Shouldn't the effects say "applies iter_swap to all pairs..."?</p>
<p><b>Proposed resolution:</b></p>
<p>In 25.2.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.reverse"> [lib.alg.reverse]</a>, replace:</p>
  <blockquote>
  Effects: For each non-negative integer i &lt;= (last - first)/2, 
  applies swap to all pairs of iterators first + i, (last - i) - 1.
  </blockquote>
<p>with:</p>
  <blockquote>
  Effects: For each non-negative integer i &lt;= (last - first)/2, 
  applies iter_swap to all pairs of iterators first + i, (last - i) - 1.
  </blockquote>
<hr>
<a name="224"><h3>224.&nbsp;clear() complexity for associative containers refers to undefined N</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Ed Brey&nbsp; <b>Date:</b>&nbsp;23 Mar 2000</p>
<p>In the associative container requirements table in 23.1.2 paragraph 7,
a.clear() has complexity "log(size()) + N". However, the meaning of N
is not defined.</p>
<p><b>Proposed resolution:</b></p>
<p>In the associative container requirements table in 23.1.2 paragraph
7, the complexity of a.clear(), change "log(size()) + N" to
"linear in <tt>size()</tt>".</p>
<p><b>Rationale:</b></p>
<p>It's the "log(size())", not the "N", that is in
error: there's no difference between <i>O(N)</i> and <i>O(N +
log(N))</i>.  The text in the standard is probably an incorrect
cut-and-paste from the range version of <tt>erase</tt>.</p>
<hr>
<a name="225"><h3>225.&nbsp;std:: algorithms use of other unqualified algorithms</h3></a><p><b>Section:</b>&nbsp;17.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.global.functions"> [lib.global.functions]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;01 Apr 2000</p>
<p>Are algorithms in std:: allowed to use other algorithms without qualification, so functions in
user namespaces might be found through Koenig lookup?</p>
<p>For example, a popular standard library implementation includes this
implementation of std::unique:</p>
<blockquote>
<pre>namespace std {
    template &lt;class _ForwardIter&gt;
    _ForwardIter unique(_ForwardIter __first, _ForwardIter __last) {
      __first = adjacent_find(__first, __last);
      return unique_copy(__first, __last, __first);
    }
    }</pre>
</blockquote>
<p>Imagine two users on opposite sides of town, each using unique on his own
sequences bounded by my_iterators . User1 looks at his standard library
implementation and says, "I know how to implement a more efficient
unique_copy for my_iterators", and writes:</p>
<blockquote>
<pre>namespace user1 {
    class my_iterator;
    // faster version for my_iterator
    my_iterator unique_copy(my_iterator, my_iterator, my_iterator);
    }</pre>
</blockquote>
<p>user1::unique_copy() is selected by Koenig lookup, as he intended.</p>
<p>User2 has other needs, and writes:</p>
<blockquote>
<pre>namespace user2 {
    class my_iterator;
    // Returns true iff *c is a unique copy of *a and *b.
    bool unique_copy(my_iterator a, my_iterator b, my_iterator c);
    }</pre>
</blockquote>
<p>User2 is shocked to find later that his fully-qualified use of
std::unique(user2::my_iterator, user2::my_iterator, user2::my_iterator) fails to
compile (if he's lucky). Looking in the standard, he sees the following Effects
clause for unique():</p>
<blockquote>
  <p>Effects: Eliminates all but the first element from every consecutive group
  of equal elements referred to by the iterator i in the range [first, last) for
  which the following corresponding conditions hold: *i == *(i - 1) or pred(*i,
  *(i - 1)) != false</p>
</blockquote>
<p>The standard gives user2 absolutely no reason to think he can interfere with
std::unique by defining names in namespace user2. His standard library has been
built with the template export feature, so he is unable to inspect the
implementation. User1 eventually compiles his code with another compiler, and
his version of unique_copy silently stops being called. Eventually, he realizes
that he was depending on an implementation detail of his library and had no
right to expect his unique_copy() to be called portably.</p>
<p>On the face of it, and given above scenario, it may seem obvious that the
implementation of unique() shown is non-conforming because it uses unique_copy()
rather than ::std::unique_copy(). Most standard library implementations,
however, seem to disagree with this notion.</p>
<p> <i>[Tokyo:&nbsp; Steve Adamczyk from
the core working group indicates that "std::" is sufficient;&nbsp;
leading "::" qualification is not required because any namespace
qualification is sufficient to suppress Koenig lookup.]</i></p>
<p><b>Proposed resolution:</b></p>
<p>Add a paragraph and a note at the end of 
17.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.global.functions"> [lib.global.functions]</a>:</p>
<blockquote>

<p>Unless otherwise specified, no global or non-member function in the
standard library shall use a function from another namespace which is
found through <i>argument-dependent name lookup</i> (3.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/basic.html#basic.lookup.koenig"> [basic.lookup.koenig]</a>).</p>

<p>[Note: the phrase "unless otherwise specified" is intended to
allow Koenig lookup in cases like that of ostream_iterators:<br>

<br>
  Effects:</p>
  <blockquote>
<p>*out_stream &lt;&lt; value;<br>
      if(delim != 0) *out_stream &lt;&lt; delim;<br>
      return (*this);</p>
    <p>--end note]</p>
  </blockquote>
</blockquote>

<p><i>[Tokyo: The LWG agrees that this is a defect in the standard, but
is as yet unsure if the proposed resolution is the best
solution. Furthermore, the LWG believes that the same problem of
unqualified library names applies to wording in the standard itself,
and has opened issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a> accordingly. Any resolution of
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a> should be coordinated with the resolution of
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#229">229</a>.]</i></p>

<p><i>[Toronto: The LWG is not sure if this is a defect in the
standard.  Most LWG members believe that an implementation of
<tt>std::unique</tt> like the one quoted in this issue is already
illegal, since, under certain circumstances, its semantics are not
those specified in the standard.  The standard's description of
<tt>unique</tt> does not say that overloading <tt>adjacent_find</tt>
should have any effect.]</i></p>

<p><i>[Curaçao: An LWG-subgroup spent an afternoon working on issues
225, 226, and 229.  Their conclusion was that the issues should be
separated into an LWG portion (Howard's paper, N1387=02-0045), and a
EWG portion (Dave will write a proposal). The LWG and EWG had
(separate) discussions of this plan the next day.  The proposed
resolution for this issue is in accordance with Howard's paper.]</i></p>

<p><b>Rationale:</b></p>
<p>It could be argued that this proposed isn't strictly necessary,
  that the Standard doesn't grant implementors license to write a
  standard function that behaves differently than specified in the
  Standard just because of an unrelated user-defined name in some
  other namespace.  However, this is at worst a clarification.  It is
  surely right that algorithsm shouldn't pick up random names, that
  user-defined names should have no effect unless otherwise specified.
  Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#226">226</a> deals with the question of when it is
  appropriate for the standard to explicitly specify otherwise.</p>
<hr>
<a name="226"><h3>226.&nbsp;User supplied specializations or overloads of namespace std function templates</h3></a><p><b>Section:</b>&nbsp;17.4.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.reserved.names"> [lib.reserved.names]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;01 Apr 2000</p>
<p>The issues are:&nbsp;</p>
<p>1. How can a 3rd party library implementor (lib1) write a version of a standard
algorithm which is specialized to work with his own class template?&nbsp;</p>
<p>2. How can another library implementor (lib2) write a generic algorithm which 
will take advantage of the specialized algorithm in lib1?</p>
<p>This appears to be the only viable answer under current language rules:</p>
<blockquote>
  <pre>namespace lib1
{
    // arbitrary-precision numbers using T as a basic unit
    template &lt;class T&gt;
    class big_num { //...
    };
    </pre>
  <pre>    // defining this in namespace std is illegal (it would be an
    // overload), so we hope users will rely on Koenig lookup
    template &lt;class T&gt;
    void swap(big_int&lt;T&gt;&amp;, big_int&lt;T&gt;&amp;);
}</pre>
  <pre>#include &lt;algorithm&gt;
namespace lib2
{
    template &lt;class T&gt;
    void generic_sort(T* start, T* end)
    {
            ...
        // using-declaration required so we can work on built-in types
        using std::swap;
        // use Koenig lookup to find specialized algorithm if available
        swap(*x, *y);
    }
}</pre>
</blockquote>
<p>This answer has some drawbacks. First of all, it makes writing lib2 difficult
and somewhat slippery. The implementor needs to remember to write the
using-declaration, or generic_sort will fail to compile when T is a built-in
type. The second drawback is that the use of this style in lib2 effectively
"reserves" names in any namespace which defines types which may
eventually be used with lib2. This may seem innocuous at first when applied to
names like swap, but consider more ambiguous names like unique_copy() instead.
It is easy to imagine the user wanting to define these names differently in his
own namespace. A definition with semantics incompatible with the standard
library could cause serious problems (see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a>).</p>
<p>Why, you may ask, can't we just partially specialize std::swap()? It's
because the language doesn't allow for partial specialization of function
templates. If you write:</p>
<blockquote>
  <pre>namespace std
{
    template &lt;class T&gt;
    void swap(lib1::big_int&lt;T&gt;&amp;, lib1::big_int&lt;T&gt;&amp;);
}</pre>
</blockquote>
<p>You have just overloaded std::swap, which is illegal under the current
language rules. On the other hand, the following full specialization is legal:</p>
<blockquote>
  <pre>namespace std
{
    template &lt;&gt;
    void swap(lib1::other_type&amp;, lib1::other_type&amp;);
}</pre>
</blockquote>

<p>This issue reflects concerns raised by the "Namespace issue
with specialized swap" thread on comp.lang.c++.moderated. A
similar set of concerns was earlier raised on the boost.org mailing
list and the ACCU-general mailing list.  Also see library reflector
message c++std-lib-7354.</p>

<p>
J. C. van Winkel points out (in c++std-lib-9565) another unexpected
fact: it's impossible to output a container of std::pair's using copy
and an ostream_iterator, as long as both pair-members are built-in or
std:: types.  That's because a user-defined operator&lt;&lt; for (for
example) std::pair&lt;const std::string, int&gt; will not be found:
lookup for operator&lt;&lt; will be performed only in namespace std.
Opinions differed on whether or not this was a defect, and, if so,
whether the defect is that something is wrong with user-defined
functionality and std, or whether it's that the standard library does
not provide an operator&lt;&lt; for std::pair&lt;&gt;.
</p>

<p><b>Proposed resolution:</b></p>

<p>Adopt the wording proposed in Howard Hinnant's paper
  N1523=03-0106, "Proposed Resolution To LWG issues 225, 226, 229".</p>


<p><i>[Tokyo: Summary, "There is no conforming way to extend
std::swap for user defined templates."&nbsp; The LWG agrees that
there is a problem.  Would like more information before
proceeding. This may be a core issue.  Core issue 229 has been opened
to discuss the core aspects of this problem. It was also noted that
submissions regarding this issue have been received from several
sources, but too late to be integrated into the issues list.
]</i></p>

<p><i>[Post-Tokyo: A paper with several proposed resolutions,
J16/00-0029==WG21/N1252, "Shades of namespace std functions
" by Alan Griffiths, is in the Post-Tokyo mailing. It
should be considered a part of this issue.]</i></p>

<p><i>[Toronto: Dave Abrahams and Peter Dimov have proposed a
resolution that involves core changes: it would add partial
specialization of function template.  The Core Working Group is
reluctant to add partial specialization of function templates.  It is
viewed as a large change, CWG believes that proposal presented leaves
some syntactic issues unanswered; if the CWG does add partial
specialization of function templates, it wishes to develop its own
proposal.  The LWG continues to believe that there is a serious
problem: there is no good way for users to force the library to use
user specializations of generic standard library functions, and in
certain cases (e.g. transcendental functions called by
<tt>valarray</tt> and <tt>complex</tt>) this is important.  Koenig
lookup isn't adequate, since names within the library must be
qualified with <tt>std</tt> (see issue 225), specialization doesn't
work (we don't have partial specialization of function templates), and
users aren't permitted to add overloads within namespace std.
]</i></p>

<p><i>[Copenhagen: Discussed at length, with no consensus.  Relevant
papers in the pre-Copenhagen mailing: N1289, N1295, N1296.  Discussion
focused on four options. (1) Relax restrictions on overloads within
namespace std. (2) Mandate that the standard library use unqualified
calls for <tt>swap</tt> and possibly other functions.  (3) Introduce
helper class templates for <tt>swap</tt> and possibly other functions.
(4) Introduce partial specialization of function templates.  Every
option had both support and opposition.  Straw poll (first number is
support, second is strongly opposed): (1) 6, 4; (2) 6, 7; (3) 3, 8;
(4) 4, 4.]</i></p>

<p><i>[Redmond: Discussed, again no consensus.  Herb presented an
argument that a user who is defining a type <tt>T</tt> with an
associated <tt>swap</tt> should not be expected to put that
<tt>swap</tt> in namespace std, either by overloading or by partial
specialization.  The argument is that <tt>swap</tt> is part of
<tt>T</tt>'s interface, and thus should to in the same namespace as
<tt>T</tt> and only in that namespace.  If we accept this argument,
the consequence is that standard library functions should use
unqualified call of <tt>swap</tt>.  (And which other functions? Any?)
A small group (Nathan, Howard, Jeremy, Dave, Matt, Walter, Marc) will
try to put together a proposal before the next meeting.]</i></p>

<p><i>[Curaçao: An LWG-subgroup spent an afternoon working on issues
225, 226, and 229.  Their conclusion was that the issues should be
separated into an LWG portion (Howard's paper, N1387=02-0045), and a
EWG portion (Dave will write a proposal). The LWG and EWG had
(separate) discussions of this plan the next day.  The proposed
resolution is the one proposed by Howard.]</i></p>

<p><i>[Santa Cruz: the LWG agreed with the general direction of
  Howard's paper, N1387.  (Roughly: Koenig lookup is disabled unless
  we say otherwise; this issue is about when we do say otherwise.)
  However, there were concerns about wording.  Howard will provide new
  wording.  Bill and Jeremy will review it.]</i></p>

<p><i>[Kona: Howard proposed the new wording.  The LWG accepted his
  proposed resolution.]</i></p>

<p><b>Rationale:</b></p>
<p>Informally: introduce a Swappable concept, and specify that the
  value types of the iterators passed to certain standard algorithms
  (such as iter_swap, swap_ranges, reverse, rotate, and sort) conform
  to that concept.  The Swappable concept will make it clear that
  these algorithms use unqualified lookup for the calls
  to <tt>swap</tt>.  Also, in <font color="red">26.3.3.3</font> paragraph 1,
  state that the valarray transcendentals use unqualified lookup.</p>
<hr>
<a name="227"><h3>227.&nbsp;std::swap() should require CopyConstructible or DefaultConstructible arguments</h3></a><p><b>Section:</b>&nbsp;25.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.swap"> [lib.alg.swap]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#TC">TC</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;09 Apr 2000</p>
<p>25.2.2 reads:</p>
<blockquote>
  <p><tt>  template&lt;class T&gt; void swap(T&amp; a, T&amp; b);</tt><br>
  <br>
  Requires:    Type T is Assignable (_lib.container.requirements_).<br>
  Effects:    Exchanges values stored in two locations.</p>
</blockquote>
<p>The only reasonable** generic implementation of swap requires construction of a 
   new temporary copy of one of its arguments:</p>
<blockquote>
<pre>template&lt;class T&gt; void swap(T&amp; a, T&amp; b);
  {
      T tmp(a);
      a = b;
      b = tmp;
  }</pre>
</blockquote>
<p>But a type which is only Assignable cannot be swapped by this implementation.</p>
<p>**Yes, there's also an unreasonable implementation which would require T to be 
   DefaultConstructible instead of CopyConstructible. I don't think this is worthy 
   of consideration:</p>
<blockquote>
<pre>template&lt;class T&gt; void swap(T&amp; a, T&amp; b);
{
    T tmp;
    tmp = a;
    a = b;
    b = tmp;
}</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Change 25.2.2 paragraph 1 from:</p>
<blockquote>
<p>  Requires: Type T is Assignable (23.1).</p>
</blockquote>
<p>to:</p>
<blockquote>
<p>  Requires: Type T is CopyConstructible (20.1.3) and Assignable (23.1)</p>
</blockquote>
<hr>
<a name="228"><h3>228.&nbsp;Incorrect specification of "..._byname" facets</h3></a><p><b>Section:</b>&nbsp;22.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.categories"> [lib.locale.categories]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;20 Apr 2000</p>
<p>The sections 22.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.byname"> [lib.locale.ctype.byname]</a>, 22.2.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt"> [lib.locale.codecvt]</a>,
<font color="red">22.2.1.6</font>, 22.2.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.numpunct.byname"> [lib.locale.numpunct.byname]</a>, 22.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.collate.byname"> [lib.locale.collate.byname]</a>, 22.2.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.time.put.byname"> [lib.locale.time.put.byname]</a>, 22.2.6.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.moneypunct.byname"> [lib.locale.moneypunct.byname]</a>, and 22.2.7.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.messages.byname"> [lib.locale.messages.byname]</a> overspecify the
definitions of the "..._byname" classes by listing a bunch
of virtual functions. At the same time, no semantics of these
functions are defined. Real implementations do not define these
functions because the functional part of the facets is actually
implemented in the corresponding base classes and the constructor of
the "..._byname" version just provides suitable date used by
these implementations. For example, the 'numpunct' methods just return
values from a struct. The base class uses a statically initialized
struct while the derived version reads the contents of this struct
from a table.  However, no virtual function is defined in
'numpunct_byname'.</p>

<p>For most classes this does not impose a problem but specifically
for 'ctype' it does: The specialization for 'ctype_byname&lt;char&gt;'
is required because otherwise the semantics would change due to the
virtual functions defined in the general version for 'ctype_byname':
In 'ctype&lt;char&gt;' the method 'do_is()' is not virtual but it is
made virtual in both 'ctype&lt;cT&gt;' and 'ctype_byname&lt;cT&gt;'.
Thus, a class derived from 'ctype_byname&lt;char&gt;' can tell whether
this class is specialized or not under the current specification:
Without the specialization, 'do_is()' is virtual while with
specialization it is not virtual.</p>
<p><b>Proposed resolution:</b></p>
<p>&nbsp; Change section 22.2.1.2 (lib.locale.ctype.byname) to become:</p>
<pre>     namespace std {
       template &lt;class charT&gt;
       class ctype_byname : public ctype&lt;charT&gt; {
       public:
         typedef ctype&lt;charT&gt;::mask mask;
         explicit ctype_byname(const char*, size_t refs = 0);
       protected:
        ~ctype_byname();             //  virtual
       };
     }</pre>
<p>&nbsp; Change section 22.2.1.6 (lib.locale.codecvt.byname) to become:</p>
<pre>    namespace std {
      template &lt;class internT, class externT, class stateT&gt;
      class codecvt_byname : public codecvt&lt;internT, externT, stateT&gt; {
      public:
       explicit codecvt_byname(const char*, size_t refs = 0);
      protected:
      ~codecvt_byname();             //  virtual
       };
     }
</pre>
<p>&nbsp; Change section 22.2.3.2 (lib.locale.numpunct.byname) to become:</p>
<pre>     namespace std {
       template &lt;class charT&gt;
       class numpunct_byname : public numpunct&lt;charT&gt; {
     //  this class is specialized for  char  and  wchar_t.
       public:
         typedef charT                char_type;
         typedef basic_string&lt;charT&gt;  string_type;
         explicit numpunct_byname(const char*, size_t refs = 0);
       protected:
        ~numpunct_byname();          //  virtual
       };
     }</pre>
<p>&nbsp; Change section 22.2.4.2 (lib.locale.collate.byname) to become:</p>
<pre>     namespace std {
       template &lt;class charT&gt;
       class collate_byname : public collate&lt;charT&gt; {
       public:
         typedef basic_string&lt;charT&gt; string_type;
         explicit collate_byname(const char*, size_t refs = 0);
       protected:
        ~collate_byname();           //  virtual
       };
     }</pre>
<p>&nbsp; Change section 22.2.5.2 (lib.locale.time.get.byname) to become:</p>
<pre>     namespace std {
       template &lt;class charT, class InputIterator = istreambuf_iterator&lt;charT&gt; &gt;
       class time_get_byname : public time_get&lt;charT, InputIterator&gt; {
       public:
         typedef time_base::dateorder dateorder;
         typedef InputIterator        iter_type</pre>
<pre>         explicit time_get_byname(const char*, size_t refs = 0);
       protected:
        ~time_get_byname();          //  virtual
       };
     }</pre>
<p>&nbsp; Change section 22.2.5.4 (lib.locale.time.put.byname) to become:</p>
<pre>     namespace std {
       template &lt;class charT, class OutputIterator = ostreambuf_iterator&lt;charT&gt; &gt;
       class time_put_byname : public time_put&lt;charT, OutputIterator&gt;
       {
       public:
         typedef charT          char_type;
         typedef OutputIterator iter_type;</pre>
<pre>         explicit time_put_byname(const char*, size_t refs = 0);
       protected:
        ~time_put_byname();          //  virtual
       };
     }"</pre>
<p>&nbsp; Change section 22.2.6.4 (lib.locale.moneypunct.byname) to become:</p>
<pre>     namespace std {
       template &lt;class charT, bool Intl = false&gt;
       class moneypunct_byname : public moneypunct&lt;charT, Intl&gt; {
       public:
         typedef money_base::pattern pattern;
         typedef basic_string&lt;charT&gt; string_type;</pre>
<pre>         explicit moneypunct_byname(const char*, size_t refs = 0);
       protected:
        ~moneypunct_byname();        //  virtual
       };
     }</pre>
<p>&nbsp; Change section 22.2.7.2 (lib.locale.messages.byname) to become:</p>
<pre>     namespace std {
       template &lt;class charT&gt;
       class messages_byname : public messages&lt;charT&gt; {
       public:
         typedef messages_base::catalog catalog;
         typedef basic_string&lt;charT&gt;    string_type;</pre>
<pre>         explicit messages_byname(const char*, size_t refs = 0);
       protected:
        ~messages_byname();          //  virtual
       };
     }</pre>
<p>Remove section 22.2.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt"> [lib.locale.codecvt]</a> completely (because in
this case only those members are defined to be virtual which are
defined to be virtual in 'ctype&lt;cT&gt;'.)</p>

<p><i>[Post-Tokyo: Dietmar Kühl submitted this issue at the request of
the LWG to solve the underlying problems raised by issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#138">138</a>.]</i></p>

<p><i>[Copenhagen: proposed resolution was revised slightly, to remove
three last virtual functions from <tt>messages_byname</tt>.]</i></p>

<hr>
<a name="229"><h3>229.&nbsp;Unqualified references of other library entities</h3></a><p><b>Section:</b>&nbsp;17.4.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.contents"> [lib.contents]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;19 Apr 2000</p>
<p>Throughout the library chapters, the descriptions of library entities refer
to other library entities without necessarily qualifying the names.</p>

<p>For example, section 25.2.2 "Swap" describes the effect of
swap_ranges in terms of the unqualified name "swap". This section
could reasonably be interpreted to mean that the library must be implemented so
as to do a lookup of the unqualified name "swap", allowing users to
override any ::std::swap function when Koenig lookup applies.</p>

<p>Although it would have been best to use explicit qualification with
"::std::" throughout, too many lines in the standard would have to be
adjusted to make that change in a Technical Corrigendum.</p>

<p>Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#182">182</a>, which addresses qualification of
<tt>size_t</tt>, is a special case of this.
</p>
<p><b>Proposed resolution:</b></p>
<p>To section 17.4.1.1 "Library contents" Add the following paragraph:</p>
<blockquote>
  <p>Whenever a name x defined in the standard library is mentioned, the name x
  is assumed to be fully qualified as ::std::x, unless explicitly described
  otherwise. For example, if the Effects section for library function F is
  described as calling library function G, the function ::std::G is meant.</p>
</blockquote>

<p><i>[Post-Tokyo: Steve Clamage submitted this issue at the request of
the LWG to solve a problem in the standard itself similar to the
problem within implementations of library identified by issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a>.  Any resolution of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#225">225</a> should be
coordinated with the resolution of this issue.]</i></p>

<p><i>[post-Toronto: Howard is undecided about whether it is
appropriate for all standard library function names referred to in
other standard library functions to be explicitly qualified by
<tt>std</tt>: it is common advice that users should define global
functions that operate on their class in the same namespace as the 
class, and this requires argument-dependent lookup if those functions
are intended to be called by library code.  Several LWG members are
concerned that valarray appears to require argument-dependent lookup,
but that the wording may not be clear enough to fall under
"unless explicitly described otherwise".]</i></p>

<p><i>[Curaçao: An LWG-subgroup spent an afternoon working on issues
225, 226, and 229.  Their conclusion was that the issues should be
separated into an LWG portion (Howard's paper, N1387=02-0045), and a
EWG portion (Dave will write a proposal). The LWG and EWG had
(separate) discussions of this plan the next day.  This paper resolves
issues 225 and 226.  In light of that resolution, the proposed
resolution for the current issue makes sense.]</i></p>

<hr>
<a name="230"><h3>230.&nbsp;Assignable specified without also specifying CopyConstructible</h3></a><p><b>Section:</b>&nbsp;17 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.library"> [lib.library]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;26 Apr 2000</p>
<p>Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#227">227</a> identified an instance (std::swap) where
Assignable was specified without also specifying
CopyConstructible. The LWG asked that the standard be searched to
determine if the same defect existed elsewhere.</p>

<p>There are a number of places (see proposed resolution below) where
Assignable is specified without also specifying
CopyConstructible. There are also several cases where both are
specified. For example, 26.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.rand.req"> [lib.rand.req]</a>.</p>
<p><b>Proposed resolution:</b></p>
<p>In  23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> table 65 for value_type:
change "T is Assignable" to "T is CopyConstructible and
Assignable"
</p>

<p>In 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> table 69 X::key_type; change
"Key is Assignable" to "Key is
CopyConstructible and Assignable"<br>
</p>

<p>In 24.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.output.iterators"> [lib.output.iterators]</a> paragraph 1, change:
</p>
<blockquote>
<p> A class or a built-in type X satisfies the requirements of an
output iterator if X is an Assignable type (23.1) and also the
following expressions are valid, as shown in Table 73:
</p>
</blockquote>
<p>to:
</p>
<blockquote>
<p> A class or a built-in type X satisfies the requirements of an
output iterator if X is a CopyConstructible (20.1.3) and Assignable
type (23.1) and also the following expressions are valid, as shown in
Table 73:
</p>
</blockquote>

<p><i>[Post-Tokyo: Beman Dawes submitted this issue at the request of
the LWG.  He asks that the 25.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.replace"> [lib.alg.replace]</a> and 25.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.fill"> [lib.alg.fill]</a> changes be studied carefully, as it is not clear that
CopyConstructible is really a requirement and may be
overspecification.]</i></p>

<p><i>[Portions of the resolution for issue 230 have been superceded by
the resolution of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#276">276</a>.]</i></p>

<p><b>Rationale:</b></p>
<p>The original proposed resolution also included changes to input
iterator, fill, and replace.  The LWG believes that those changes are
not necessary.  The LWG considered some blanket statement, where an
Assignable type was also required to be Copy Constructible, but
decided against this because fill and replace really don't require the
Copy Constructible property.</p>
<hr>
<a name="231"><h3>231.&nbsp;Precision in iostream?</h3></a><p><b>Section:</b>&nbsp;22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;James Kanze, Stephen Clamage&nbsp; <b>Date:</b>&nbsp; 25 Apr 2000</p>
<p>What is the following program supposed to output?</p>
<pre>#include &lt;iostream&gt;

    int
    main()
    {
        std::cout.setf( std::ios::scientific , std::ios::floatfield ) ;
        std::cout.precision( 0 ) ;
        std::cout &lt;&lt; 1.00 &lt;&lt; '\n' ;
        return 0 ;
    }</pre>
<p>From my C experience, I would expect "1e+00"; this is what 
<tt>printf("%.0e" , 1.00 );</tt> does. G++ outputs 
"1.000000e+00".</p>

<p>The only indication I can find in the standard is 22.2.2.2.2/11,
where it says "For conversion from a floating-point type, if
(flags &amp; fixed) != 0 or if str.precision() &gt; 0, then
str.precision() is specified in the conversion specification."
This is an obvious error, however, fixed is not a mask for a field,
but a value that a multi-bit field may take -- the results of and'ing
fmtflags with ios::fixed are not defined, at least not if
ios::scientific has been set. G++'s behavior corresponds to what might
happen if you do use (flags &amp; fixed) != 0 with a typical
implementation (floatfield == 3 &lt;&lt; something, fixed == 1
&lt;&lt; something, and scientific == 2 &lt;&lt; something).</p>

<p>Presumably, the intent is either (flags &amp; floatfield) != 0, or
(flags &amp; floatfield) == fixed; the first gives something more or
less like the effect of precision in a printf floating point
conversion. Only more or less, of course. In order to implement printf
formatting correctly, you must know whether the precision was
explicitly set or not. Say by initializing it to -1, instead of 6, and
stating that for floating point conversions, if precision &lt; -1, 6
will be used, for fixed point, if precision &lt; -1, 1 will be used,
etc. Plus, of course, if precision == 0 and flags &amp; floatfield ==
0, 1 should be = used. But it probably isn't necessary to emulate all
of the anomalies of printf:-).</p>
<p><b>Proposed resolution:</b></p>
<p>
Replace 22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>, paragraph 11, with the following 
sentence:
</p>
<blockquote>
For conversion from a floating-point type,
<tt><i>str</i>.precision()</tt> is specified in the conversion
specification.
</blockquote>
<p><b>Rationale:</b></p>
<p>The floatfield determines whether numbers are formatted as if
with %f, %e, or %g.  If the <tt>fixed</tt> bit is set, it's %f,
if <tt>scientific</tt> it's %e, and if both bits are set, or 
neither, it's %g.</p>
<p>Turning to the C standard, a precision of 0 is meaningful
for %f and %e.  For %g, precision 0 is taken to be the same as 
precision 1.</p>
<p>The proposed resolution has the effect that if neither
<tt>fixed</tt> nor <tt>scientific</tt> is set we'll be
specifying a precision of 0, which will be internally
turned into 1.  There's no need to call it out as a special
case.</p>
<p>The output of the above program will be "1e+00".</p>

<p><i>[Post-Curaçao: Howard provided improved wording covering the case
where precision is 0 and mode is %g.]</i></p>

<hr>
<a name="232"><h3>232.&nbsp;"depends" poorly defined in 17.4.3.1</h3></a><p><b>Section:</b>&nbsp;17.4.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.reserved.names"> [lib.reserved.names]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Peter Dimov&nbsp; <b>Date:</b>&nbsp;18 Apr 2000</p>
<p>17.4.3.1/1 uses the term "depends" to limit the set of allowed
specializations of standard templates to those that "depend on a
user-defined name of external linkage."</p>
<p>This term, however, is not adequately defined, making it possible to
construct a specialization that is, I believe, technically legal according to
17.4.3.1/1, but that specializes a standard template for a built-in type such as
'int'.</p>
<p>The following code demonstrates the problem:</p>
<blockquote>
  <pre>#include &lt;algorithm&gt;</pre>
  <pre>template&lt;class T&gt; struct X
{
 typedef T type;
};</pre>
  <pre>namespace std
{
 template&lt;&gt; void swap(::X&lt;int&gt;::type&amp; i, ::X&lt;int&gt;::type&amp; j);
}</pre>
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Change "user-defined name" to "user-defined
type".</p>
<p><b>Rationale:</b></p>
<p>This terminology is used in section 2.5.2 and 4.1.1 of <i>The C++
Programming Language</i>.  It disallows the example in the issue,
since the underlying type itself is not user-defined.  The only
possible problem I can see is for non-type templates, but there's no
possible way for a user to come up with a specialization for bitset,
for example, that might not have already been specialized by the
implementor?</p>

<p><i>[Toronto: this may be related to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#120">120</a>.]</i></p>

<p><i>[post-Toronto: Judy provided the above proposed resolution and
rationale.]</i></p>
<hr>
<a name="234"><h3>234.&nbsp;Typos in allocator definition</h3></a><p><b>Section:</b>&nbsp;20.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.allocator.members"> [lib.allocator.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;24 Apr 2000</p>
<p>In paragraphs 12 and 13 the effects of <tt>construct()</tt> and
<tt>destruct()</tt> are described as returns but the functions actually
return <tt>void</tt>.</p>
<p><b>Proposed resolution:</b></p>
<p>Substitute "Returns" by "Effect".</p>
<hr>
<a name="235"><h3>235.&nbsp;No specification of default ctor for reverse_iterator</h3></a><p><b>Section:</b>&nbsp;24.4.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iterator"> [lib.reverse.iterator]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;24 Apr 2000</p>
<p>The declaration of <tt>reverse_iterator</tt> lists a default
constructor.  However, no specification is given what this constructor
should do.</p>
<p><b>Proposed resolution:</b></p>
  <p>In section 24.4.1.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.cons"> [lib.reverse.iter.cons]</a> add the following
  paragraph:</p>
      <blockquote>
      <p><tt>reverse_iterator()</tt></p>

      <p>Default initializes <tt>current</tt>. Iterator operations
      applied to the resulting iterator have defined behavior if and
      only if the corresponding operations are defined on a default
      constructed iterator of type <tt>Iterator</tt>.</p>
      </blockquote>
  <p><i>[pre-Copenhagen: Dietmar provide wording for proposed
  resolution.]</i></p>
<hr>
<a name="237"><h3>237.&nbsp;Undefined expression in complexity specification</h3></a><p><b>Section:</b>&nbsp;23.2.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.cons"> [lib.deque.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;24 Apr 2000</p>
<p>The complexity specification in paragraph 6 says that the complexity
is linear in <tt>first - last</tt>. Even if <tt>operator-()</tt> is
defined on iterators this term is in general undefined because it
would have to be <tt>last - first</tt>.</p>
<p><b>Proposed resolution:</b></p>
  <p>Change paragraph 6 from</p>
     <blockquote>Linear in <i>first - last</i>.</blockquote>
  <p>to become</p>
     <blockquote>Linear in <i>distance(first, last)</i>.</blockquote>
<hr>
<a name="238"><h3>238.&nbsp;Contradictory results of stringbuf initialization.</h3></a><p><b>Section:</b>&nbsp;27.7.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.cons"> [lib.stringbuf.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dietmar Kühl&nbsp; <b>Date:</b>&nbsp;11 May 2000</p>
<p>In 27.7.1.1 paragraph 4 the results of calling the constructor of
'basic_stringbuf' are said to be <tt>str() == str</tt>. This is fine
that far but consider this code:</p>

<pre>  std::basic_stringbuf&lt;char&gt; sbuf("hello, world", std::ios_base::openmode(0));
  std::cout &lt;&lt; "'" &lt;&lt; sbuf.str() &lt;&lt; "'\n";
</pre>

<p>Paragraph 3 of 27.7.1.1 basically says that in this case neither
the output sequence nor the input sequence is initialized and
paragraph 2 of 27.7.1.2 basically says that <tt>str()</tt> either
returns the input or the output sequence. None of them is initialized,
ie. both are empty, in which case the return from <tt>str()</tt> is
defined to be <tt>basic_string&lt;cT&gt;()</tt>.</p>

<p>However, probably only test cases in some testsuites will detect this
"problem"...</p>
<p><b>Proposed resolution:</b></p>
<p>Remove 27.7.1.1 paragraph 4.</p>
<p><b>Rationale:</b></p>
<p>We could fix 27.7.1.1 paragraph 4, but there would be no point.  If
we fixed it, it would say just the same thing as text that's already
in the standard.</p>
<hr>
<a name="239"><h3>239.&nbsp;Complexity of unique() and/or unique_copy incorrect</h3></a><p><b>Section:</b>&nbsp;25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;May 15 2000</p>
<p>The complexity of unique and unique_copy are inconsistent with each
other and inconsistent with the implementations.&nbsp; The standard
specifies:</p>

<p>for unique():</p>

<blockquote>-3- Complexity: If the range (last - first) is not empty, exactly
(last - first) - 1 applications of the corresponding predicate, otherwise
no applications of the predicate.</blockquote>

<p>for unique_copy():</p>

<blockquote>-7- Complexity: Exactly last - first applications of the corresponding
predicate.</blockquote>

<p>
The implementations do it the other way round: unique() applies the
predicate last-first times and unique_copy() applies it last-first-1
times.</p>

<p>As both algorithms use the predicate for pair-wise comparison of
sequence elements I don't see a justification for unique_copy()
applying the predicate last-first times, especially since it is not
specified to which pair in the sequence the predicate is applied
twice.</p>
<p><b>Proposed resolution:</b></p>
<p>Change both complexity sections in 25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a> to:</p>

<blockquote>Complexity: For nonempty ranges, exactly last - first - 1
applications of the corresponding predicate.</blockquote>

<hr>
<a name="240"><h3>240.&nbsp;Complexity of adjacent_find() is meaningless</h3></a><p><b>Section:</b>&nbsp;25.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.adjacent.find"> [lib.alg.adjacent.find]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;May 15 2000</p>
<p>The complexity section of adjacent_find is defective:</p>

<blockquote>
<pre>template &lt;class ForwardIterator&gt;
ForwardIterator adjacent_find(ForwardIterator first, ForwardIterator last
                              BinaryPredicate pred);
</pre>

<p>-1- Returns: The first iterator i such that both i and i + 1 are in
the range [first, last) for which the following corresponding
conditions hold: *i == *(i + 1), pred(*i, *(i + 1)) != false. Returns
last if no such iterator is found.</p>

<p>-2- Complexity: Exactly find(first, last, value) - first applications
of the corresponding predicate.
</p>
</blockquote>

<p>In the Complexity section, it is not defined what "value"
is supposed to mean. My best guess is that "value" means an
object for which one of the conditions pred(*i,value) or
pred(value,*i) is true, where i is the iterator defined in the Returns
section. However, the value type of the input sequence need not be
equality-comparable and for this reason the term find(first, last,
value) - first is meaningless.</p>

<p>A term such as find_if(first, last, bind2nd(pred,*i)) - first or
find_if(first, last, bind1st(pred,*i)) - first might come closer to
the intended specification.  Binders can only be applied to function
objects that have the function call operator declared const, which is
not required of predicates because they can have non-const data
members. For this reason, a specification using a binder could only be
an "as-if" specification.</p>
<p><b>Proposed resolution:</b></p>
<p>Change the complexity section in 25.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.adjacent.find"> [lib.alg.adjacent.find]</a> to:</p>
<blockquote>
For a nonempty range, exactly <tt>min((<i>i</i> - <i>first</i>) + 1,
(<i>last</i> - <i>first</i>) - 1)</tt> applications of the
corresponding predicate, where <i>i</i> is <tt>adjacent_find</tt>'s
return value.
</blockquote>

<p><i>[Copenhagen: the original resolution specified an upper
bound.  The LWG preferred an exact count.]</i></p>

<hr>
<a name="241"><h3>241.&nbsp;Does unique_copy() require CopyConstructible and Assignable?</h3></a><p><b>Section:</b>&nbsp;25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;May 15 2000</p>

<p>Some popular implementations of unique_copy() create temporary
copies of values in the input sequence, at least if the input iterator
is a pointer.  Such an implementation is built on the assumption that
the value type is CopyConstructible and Assignable.</p>

<p>It is common practice in the standard that algorithms explicitly
specify any additional requirements that they impose on any of the
types used by the algorithm. An example of an algorithm that creates
temporary copies and correctly specifies the additional requirements
is accumulate(), 26.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.rand.req"> [lib.rand.req]</a>.</p>

<p>Since the specifications of unique() and unique_copy() do not
require CopyConstructible and Assignable of the InputIterator's value
type the above mentioned implementations are not standard-compliant. I
cannot judge whether this is a defect in the standard or a defect in
the implementations.</p>
<p><b>Proposed resolution:</b></p>
<p>In 25.2.8 change:</p>

<blockquote>
-4- Requires: The ranges [first, last) and [result, result+(last-first))
shall not overlap.
</blockquote>

<p>to:</p>

<blockquote>
  <p>-4- Requires: The ranges [first, last) and [result,
  result+(last-first)) shall not overlap. The expression *result =
  *first must be valid. If neither InputIterator nor OutputIterator
  meets the requirements of forward iterator then the value type of
  InputIterator must be copy constructible. Otherwise copy
  constructible is not required. </p>
</blockquote>

<p><i>[Redmond: the original proposed resolution didn't impose an
explicit requirement that the iterator's value type must be copy
constructible, on the grounds that an input iterator's value type must
always be copy constructible.  Not everyone in the LWG thought that
this requirement was clear from table 72.  It has been suggested that
it might be possible to implement <tt>unique_copy</tt> without
requiring assignability, although current implementations do impose
that requirement.  Howard provided new wording.]</i></p>

<p><i>[
Curaçao: The LWG changed the PR editorially to specify
"neither...nor...meet..." as clearer than
"both...and...do not meet...". Change believed to be so
minor as not to require re-review.
]</i></p>

<hr>
<a name="242"><h3>242.&nbsp;Side effects of function objects</h3></a><p><b>Section:</b>&nbsp;25.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.transform"> [lib.alg.transform]</a>, 26.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.rand"> [lib.rand]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Angelika Langer&nbsp; <b>Date:</b>&nbsp;May 15 2000</p>
<p>The algorithms transform(), accumulate(), inner_product(),
partial_sum(), and adjacent_difference() require that the function
object supplied to them shall not have any side effects.</p>

<p>The standard defines a side effect in 1.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/intro.html#intro.execution"> [intro.execution]</a> as:</p>
<blockquote>-7- Accessing an object designated by a volatile lvalue (basic.lval),
modifying an object, calling a library I/O function, or calling a function
that does any of those operations are all side effects, which are changes
in the state of the execution environment.</blockquote>

<p>As a consequence, the function call operator of a function object supplied
to any of the algorithms listed above cannot modify data members, cannot
invoke any function that has a side effect, and cannot even create and
modify temporary objects.&nbsp; It is difficult to imagine a function object
that is still useful under these severe limitations. For instance, any
non-trivial transformator supplied to transform() might involve creation
and modification of temporaries, which is prohibited according to the current
wording of the standard.</p>

<p>On the other hand, popular implementations of these algorithms exhibit
uniform and predictable behavior when invoked with a side-effect-producing
function objects. It looks like the strong requirement is not needed for
efficient implementation of these algorithms.</p>

<p>The requirement of&nbsp; side-effect-free function objects could be
replaced by a more relaxed basic requirement (which would hold for all
function objects supplied to any algorithm in the standard library):</p>
<blockquote>A function objects supplied to an algorithm shall not invalidate
any iterator or sequence that is used by the algorithm. Invalidation of
the sequence includes destruction of the sorting order if the algorithm
relies on the sorting order (see section 25.3 - Sorting and related operations
[lib.alg.sorting]).</blockquote>

<p>I can't judge whether it is intended that the function objects supplied
to transform(), accumulate(), inner_product(), partial_sum(), or adjacent_difference()
shall not modify sequence elements through dereferenced iterators.</p>

<p>It is debatable whether this issue is a defect or a change request.
Since the consequences for user-supplied function objects are drastic and
limit the usefulness of the algorithms significantly I would consider it
a defect.</p>
<p><b>Proposed resolution:</b></p>

<p><i>Things to notice about these changes:</i></p>

<ol>
<li> <i>The fully-closed ("[]" as opposed to half-closed "[)" ranges
     are intentional. we want to prevent side-effects from
     invalidating the end iterators.</i>
</li>

<li> <i>That has the unintentional side-effect of prohibiting
     modification of the end element as a side-effect. This could
     conceivably be significant in some cases.</i>
</li>

<li> <i>The wording also prevents side-effects from modifying elements
     of the output sequence. I can't imagine why anyone would want
     to do this, but it is arguably a restriction that implementors
     don't need to place on users.</i>
</li>

<li> <i>Lifting the restrictions imposed in #2 and #3 above is possible
     and simple, but would require more verbiage.</i>
</li>
</ol>

<p>Change 25.2.3/2 from:</p>

<blockquote>
   -2- Requires: op and binary_op shall not have any side effects.
</blockquote>

<p>to:</p>

<blockquote>
  -2- Requires: in the ranges [first1, last1], [first2, first2 +
  (last1 - first1)] and [result, result + (last1- first1)], op and
  binary_op shall neither modify elements nor invalidate iterators or
  subranges.
  [Footnote: The use of fully closed ranges is intentional --end footnote]
</blockquote>


<p>Change 25.2.3/2 from:</p>

<blockquote>
   -2- Requires: op and binary_op shall not have any side effects. 
</blockquote>

<p>to:</p>

<blockquote>
  -2- Requires: op and binary_op shall not invalidate iterators or
   subranges, or modify elements in the ranges [first1, last1],
   [first2, first2 + (last1 - first1)], and [result, result + (last1
   - first1)].
  [Footnote: The use of fully closed ranges is intentional --end footnote]
</blockquote>


<p>Change 26.4.1/2 from:</p>

<blockquote>
  -2- Requires: T must meet the requirements of CopyConstructible
   (lib.copyconstructible) and Assignable (lib.container.requirements)
   types. binary_op shall not cause side effects.
</blockquote>

<p>to:</p>

<blockquote>
  -2- Requires: T must meet the requirements of CopyConstructible
   (lib.copyconstructible) and Assignable
   (lib.container.requirements) types. In the range [first, last],
   binary_op shall neither modify elements nor invalidate iterators
   or subranges.
  [Footnote: The use of a fully closed range is intentional --end footnote]
</blockquote>

<p>Change 26.4.2/2 from:</p>

<blockquote>
  -2- Requires: T must meet the requirements of CopyConstructible
   (lib.copyconstructible) and Assignable (lib.container.requirements)
   types. binary_op1 and binary_op2 shall not cause side effects.
</blockquote>

<p>to:</p>

<blockquote>
  -2- Requires: T must meet the requirements of CopyConstructible
   (lib.copyconstructible) and Assignable (lib.container.requirements)
   types. In the ranges [first, last] and [first2, first2 + (last -
   first)], binary_op1 and binary_op2 shall neither modify elements
   nor invalidate iterators or subranges.
  [Footnote: The use of fully closed ranges is intentional --end footnote]
</blockquote>


<p>Change 26.4.3/4 from:</p>

<blockquote>
  -4- Requires: binary_op is expected not to have any side effects.
</blockquote>

<p>to:</p>

<blockquote>
  -4- Requires: In the ranges [first, last] and [result, result +
   (last - first)], binary_op shall neither modify elements nor
   invalidate iterators or subranges.
  [Footnote: The use of fully closed ranges is intentional --end footnote]
</blockquote>

<p>Change 26.4.4/2 from:</p>

<blockquote>
  -2- Requires: binary_op shall not have any side effects.
</blockquote>

<p>to:</p>

<blockquote>
  -2- Requires: In the ranges [first, last] and [result, result +
   (last - first)], binary_op shall neither modify elements nor
   invalidate iterators or subranges.
  [Footnote: The use of fully closed ranges is intentional --end footnote]
</blockquote>

<p><i>[Toronto: Dave Abrahams supplied wording.]</i></p>

<p><i>[Copenhagen: Proposed resolution was modified slightly. Matt
added footnotes pointing out that the use of closed ranges was
intentional.]</i></p>

<hr>
<a name="243"><h3>243.&nbsp;<tt>get</tt> and <tt>getline</tt> when sentry reports failure</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;May 15 2000</p>
<p>basic_istream&lt;&gt;::get(), and basic_istream&lt;&gt;::getline(),
are unclear with respect to the behavior and side-effects of the named
functions in case of an error.</p>

<p>27.6.1.3, p1 states that "... If the sentry object returns
true, when converted to a value of type bool, the function endeavors
to obtain the requested input..." It is not clear from this (or
the rest of the paragraph) what precisely the behavior should be when
the sentry ctor exits by throwing an exception or when the sentry
object returns false.  In particular, what is the number of characters
extracted that gcount() returns supposed to be?</p>

<p>27.6.1.3 p8 and p19 say about the effects of get() and getline():
"...  In any case, it then stores a null character (using
charT()) into the next successive location of the array." Is not
clear whether this sentence applies if either of the conditions above
holds (i.e., when sentry fails).</p>
<p><b>Proposed resolution:</b></p>
<p>Add to 27.6.1.3, p1 after the sentence</p>

<blockquote>
"... If the sentry object returns true, when converted to a value of
type bool, the function endeavors to obtain the requested input."
</blockquote>

<p>the following</p>


<blockquote>
"Otherwise, if the sentry constructor exits by throwing an exception or
if the sentry object returns false, when converted to a value of type
bool, the function returns without attempting to obtain any input. In
either case the number of extracted characters is set to 0; unformatted
input functions taking a character array of non-zero size as an argument
shall also store a null character (using charT()) in the first location
of the array."
</blockquote>
<p><b>Rationale:</b></p>
<p>Although the general philosophy of the input functions is that the
argument should not be modified upon failure, <tt>getline</tt>
historically added a terminating null unconditionally.  Most
implementations still do that.  Earlier versions of the draft standard
had language that made this an unambiguous requirement; those words
were moved to a place where their context made them less clear.  See
Jerry Schwarz's message c++std-lib-7618.</p>
<hr>
<a name="247"><h3>247.&nbsp;<tt>vector</tt>, <tt>deque::insert</tt> complexity</h3></a><p><b>Section:</b>&nbsp;23.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.stack"> [lib.stack]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Lisa Lippincott&nbsp; <b>Date:</b>&nbsp;06 June 2000</p>
<p>Paragraph 2 of 23.2.4.3 [lib.vector.modifiers] describes the complexity
of <tt>vector::insert</tt>:</p>

   <blockquote>
   Complexity: If first and last are forward iterators, bidirectional
   iterators, or random access iterators, the complexity is linear in
   the number of elements in the range [first, last) plus the distance
   to the end of the vector. If they are input iterators, the complexity
   is proportional to the number of elements in the range [first, last)
   times the distance to the end of the vector.
   </blockquote>

<p>First, this fails to address the non-iterator forms of
<tt>insert</tt>.</p>

<p>Second, the complexity for input iterators misses an edge case --
it requires that an arbitrary number of elements can be added at
the end of a <tt>vector</tt> in constant time.</p>

<p>I looked to see if <tt>deque</tt> had a similar problem, and was
surprised to find that <tt>deque</tt> places no requirement on the
complexity of inserting multiple elements (23.2.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.array.size"> [lib.array.size]</a>,
paragraph 3):</p>

   <blockquote>
   Complexity: In the worst case, inserting a single element into a
   deque takes time linear in the minimum of the distance from the
   insertion point to the beginning of the deque and the distance
   from the insertion point to the end of the deque. Inserting a
   single element either at the beginning or end of a deque always
   takes constant time and causes a single call to the copy constructor
   of T.
   </blockquote>
<p><b>Proposed resolution:</b></p>

<p>Change Paragraph 2 of 23.2.4.3 [lib.vector.modifiers] to</p>
   <blockquote>
   Complexity: The complexity is linear in the number of elements 
   inserted plus the distance to the end of the vector.
   </blockquote>

   <p><i>[For input iterators, one may achieve this complexity by first
   inserting at the end of the <tt>vector</tt>, and then using
   <tt>rotate</tt>.]</i></p>

<p>Change 23.2.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.array.size"> [lib.array.size]</a>, paragraph 3, to:</p>

   <blockquote>
   Complexity: The complexity is linear in the number of elements 
   inserted plus the shorter of the distances to the beginning and
   end of the deque.  Inserting a single element at either the
   beginning or the end of a deque causes a single call to the copy
   constructor of T.
   </blockquote>

<p><b>Rationale:</b></p>
<p>This is a real defect, and proposed resolution fixes it: some
  complexities aren't specified that should be.  This proposed
  resolution does constrain deque implementations (it rules out the
  most naive possible implementations), but the LWG doesn't see a
  reason to permit that implementation.</p>
<hr>
<a name="248"><h3>248.&nbsp;time_get fails to set eofbit</h3></a><p><b>Section:</b>&nbsp;22.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.category.time"> [lib.category.time]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;22 June 2000</p>
<p>There is no requirement that any of time_get member functions set
ios::eofbit when they reach the end iterator while parsing their input.
Since members of both the num_get and money_get facets are required to
do so (22.2.2.1.2, and 22.2.6.1.2, respectively), time_get members
should follow the same requirement for consistency.</p>
<p><b>Proposed resolution:</b></p>
<p>Add paragraph 2 to section 22.2.5.1 with the following text:</p>

<blockquote>
If the end iterator is reached during parsing by any of the get()
member functions, the member sets ios_base::eofbit in err.
</blockquote>
<p><b>Rationale:</b></p>
<p>Two alternative resolutions were proposed.  The LWG chose this one
because it was more consistent with the way eof is described for other
input facets.</p>
<hr>
<a name="250"><h3>250.&nbsp;splicing invalidates iterators</h3></a><p><b>Section:</b>&nbsp;23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Brian Parker &nbsp; <b>Date:</b>&nbsp;14 Jul 2000</p>
<p>
Section 23.2.2.4 [lib.list.ops] states that
</p>
<pre>  void splice(iterator position, list&lt;T, Allocator&gt;&amp; x);
</pre>
<p>
<i>invalidates</i> all iterators and references to list <tt>x</tt>.
</p>

<p>
This is unnecessary and defeats an important feature of splice. In
fact, the SGI STL guarantees that iterators to <tt>x</tt> remain valid
after <tt>splice</tt>.
</p>
<p><b>Proposed resolution:</b></p>

<p>Add a footnote to 23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>, paragraph 1:</p>
<blockquote>
[<i>Footnote:</i> As specified in 20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>, paragraphs
4-5, the semantics described in this clause applies only to the case
where allocators compare equal.  --end footnote]
</blockquote>

<p>In 23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>, replace paragraph 4 with:</p>
<blockquote>
Effects: Inserts the contents of x before position and x becomes 
empty.  Pointers and references to the moved elements of x now refer to 
those same elements but as members of *this.  Iterators referring to the 
moved elements will continue to refer to their elements, but they now 
behave as iterators into *this, not into x.
</blockquote>

<p>In 23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>, replace paragraph 7 with:</p>
<blockquote>
Effects: Inserts an element pointed to by i from list x before 
position and removes the element from x. The result is unchanged if 
position == i or position == ++i.  Pointers and references to *i continue 
to refer to this same element but as a member of *this.  Iterators to *i 
(including i itself) continue to refer to the same element, but now 
behave as iterators into *this, not into x.
</blockquote>

<p>In 23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>, replace paragraph 12 with:</p>
<blockquote>
Requires: [first, last) is a valid range in x. The result is 
undefined if position is an iterator in the range [first, last).  
Pointers and references to the moved elements of x now refer to those 
same elements but as members of *this.  Iterators referring to the moved 
elements will continue to refer to their elements, but they now behave as 
iterators into *this, not into x.
</blockquote>

<p><i>[pre-Copenhagen: Howard provided wording.]</i></p>
<p><b>Rationale:</b></p>
<p>The original proposed resolution said that iterators and references
would remain "valid".  The new proposed resolution clarifies what that
means.  Note that this only applies to the case of equal allocators.
From 20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a> paragraph 4, the behavior of list when
allocators compare nonequal is outside the scope of the standard.</p>
<hr>
<a name="251"><h3>251.&nbsp;basic_stringbuf missing allocator_type</h3></a><p><b>Section:</b>&nbsp;27.7.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf"> [lib.stringbuf]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;28 Jul 2000</p>
<p>The synopsis for the template class <tt>basic_stringbuf</tt>
doesn't list a typedef for the template parameter
<tt>Allocator</tt>. This makes it impossible to determine the type of
the allocator at compile time. It's also inconsistent with all other
template classes in the library that do provide a typedef for the
<tt>Allocator</tt> parameter.</p>
<p><b>Proposed resolution:</b></p>
<p>Add to the synopses of the class templates basic_stringbuf (27.7.1),
basic_istringstream (27.7.2), basic_ostringstream (27.7.3), and 
basic_stringstream (27.7.4) the typedef:</p>
<pre>  typedef Allocator allocator_type;
</pre>
<hr>
<a name="252"><h3>252.&nbsp;missing casts/C-style casts used in iostreams</h3></a><p><b>Section:</b>&nbsp;27.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.string.streams"> [lib.string.streams]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;28 Jul 2000</p>
<p>27.7.2.2, p1 uses a C-style cast rather than the more appropriate
const_cast&lt;&gt; in the Returns clause for basic_istringstream&lt;&gt;::rdbuf().
The same C-style cast is being used in 27.7.3.2, p1, D.7.2.2, p1, and
D.7.3.2, p1, and perhaps elsewhere. 27.7.6, p1 and D.7.2.2, p1 are missing
the cast altogether.</p>

<p>C-style casts have not been deprecated, so the first part of this
issue is stylistic rather than a matter of correctness.</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.7.2.2, p1 replace </p>
<pre>  -1- Returns: (basic_stringbuf&lt;charT,traits,Allocator&gt;*)&amp;sb.</pre>

<p>with</p>
<pre>  -1- Returns: const_cast&lt;basic_stringbuf&lt;charT,traits,Allocator&gt;*&gt;(&amp;sb).</pre>


<p>In 27.7.3.2, p1 replace</p>
<pre>  -1- Returns: (basic_stringbuf&lt;charT,traits,Allocator&gt;*)&amp;sb.</pre>

<p>with</p>
<pre>  -1- Returns: const_cast&lt;basic_stringbuf&lt;charT,traits,Allocator&gt;*&gt;(&amp;sb).</pre>

<p>In 27.7.6, p1, replace</p>
<pre>  -1- Returns: &amp;sb</pre>

<p>with</p>
<pre>  -1- Returns: const_cast&lt;basic_stringbuf&lt;charT,traits,Allocator&gt;*&gt;(&amp;sb).</pre>

<p>In D.7.2.2, p1 replace</p>
<pre>  -2- Returns: &amp;sb. </pre>

<p>with</p>
<pre>  -2- Returns: const_cast&lt;strstreambuf*&gt;(&amp;sb).</pre>
<hr>
<a name="253"><h3>253.&nbsp;valarray helper functions are almost entirely useless</h3></a><p><b>Section:</b>&nbsp;26.5.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.valarray.cons"> [lib.valarray.cons]</a>, 26.5.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.valarray.assign"> [lib.valarray.assign]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Robert Klarer&nbsp; <b>Date:</b>&nbsp;31 Jul 2000</p>
<p>This discussion is adapted from message c++std-lib-7056 posted
November 11, 1999.  I don't think that anyone can reasonably claim
that the problem described below is NAD.</p>

<p>These valarray constructors can never be called:</p>

<pre>   template &lt;class T&gt;
         valarray&lt;T&gt;::valarray(const slice_array&lt;T&gt; &amp;);
   template &lt;class T&gt;
         valarray&lt;T&gt;::valarray(const gslice_array&lt;T&gt; &amp;);
   template &lt;class T&gt;
         valarray&lt;T&gt;::valarray(const mask_array&lt;T&gt; &amp;);
   template &lt;class T&gt;
         valarray&lt;T&gt;::valarray(const indirect_array&lt;T&gt; &amp;);
</pre>

<p>Similarly, these valarray assignment operators cannot be
called:</p>

<pre>     template &lt;class T&gt;
     valarray&lt;T&gt; valarray&lt;T&gt;::operator=(const slice_array&lt;T&gt; &amp;);
     template &lt;class T&gt;
     valarray&lt;T&gt; valarray&lt;T&gt;::operator=(const gslice_array&lt;T&gt; &amp;);
     template &lt;class T&gt;
     valarray&lt;T&gt; valarray&lt;T&gt;::operator=(const mask_array&lt;T&gt; &amp;);
     template &lt;class T&gt;
     valarray&lt;T&gt; valarray&lt;T&gt;::operator=(const indirect_array&lt;T&gt; &amp;);
</pre>

<p>Please consider the following example:</p>

<pre>   #include &lt;valarray&gt;
   using namespace std;

   int main()
   {
       valarray&lt;double&gt; va1(12);
       valarray&lt;double&gt; va2(va1[slice(1,4,3)]); // line 1
   }
</pre>


<p>Since the valarray va1 is non-const, the result of the sub-expression
va1[slice(1,4,3)] at line 1 is an rvalue of type const
std::slice_array&lt;double&gt;.  This slice_array rvalue is then used to
construct va2.  The constructor that is used to construct va2 is
declared like this:</p>

<pre>     template &lt;class T&gt;
     valarray&lt;T&gt;::valarray(const slice_array&lt;T&gt; &amp;);
</pre>

<p>Notice the constructor's const reference parameter.  When the
constructor is called, a slice_array must be bound to this reference.
The rules for binding an rvalue to a const reference are in 8.5.3,
paragraph 5 (see also 13.3.3.1.4).  Specifically, paragraph 5
indicates that a second slice_array rvalue is constructed (in this
case copy-constructed) from the first one; it is this second rvalue
that is bound to the reference parameter.  Paragraph 5 also requires
that the constructor that is used for this purpose be callable,
regardless of whether the second rvalue is elided.  The
copy-constructor in this case is not callable, however, because it is
private.  Therefore, the compiler should report an error.</p>

<p>Since slice_arrays are always rvalues, the valarray constructor that has a
parameter of type const slice_array&lt;T&gt; &amp; can never be called.  The
same reasoning applies to the three other constructors and the four
assignment operators that are listed at the beginning of this post.
Furthermore, since these functions cannot be called, the valarray helper
classes are almost entirely useless.</p>
<p><b>Proposed resolution:</b></p>
<p>slice_array:</p>
<ul>
<li> Make the copy constructor and copy-assignment operator declarations
     public in the slice_array class template definition in 26.5.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.slice.array"> [lib.template.slice.array]</a> </li>
<li> remove paragraph 3 of 26.5.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.slice.array"> [lib.template.slice.array]</a>
</li>
<li> remove the copy constructor declaration from 26.5.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.cons.slice.arr"> [lib.cons.slice.arr]</a>
</li>
<li> change paragraph 1 of 26.5.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.cons.slice.arr"> [lib.cons.slice.arr]</a> to read "This constructor is declared
    to be private.  This constructor need not be defined."</li>
<li> remove the first sentence of paragraph 1 of 26.5.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.slice.arr.assign"> [lib.slice.arr.assign]</a>
</li>
<li> Change the first three words of the second sentence of paragraph 1 of
    26.5.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.slice.arr.assign"> [lib.slice.arr.assign]</a> to "These assignment operators have"</li>
</ul>

<p>gslice_array:</p>
<ul>
<li> Make the copy constructor and copy-assignment operator declarations
    public in the gslice_array class template definition in 26.5.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.gslice.array"> [lib.template.gslice.array]</a> </li>
<li> remove the note in paragraph 3 of 26.5.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.gslice.array"> [lib.template.gslice.array]</a>
</li>
<li> remove the copy constructor declaration from 26.5.7.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.gslice.array.cons"> [lib.gslice.array.cons]</a>
</li>
<li> change paragraph 1 of 26.5.7.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.gslice.array.cons"> [lib.gslice.array.cons]</a> to read "This constructor is declared
    to be private.  This constructor need not be defined."</li>
<li> remove the first sentence of paragraph 1 of 26.5.7.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.gslice.array.assign"> [lib.gslice.array.assign]</a>
</li>
<li> Change the first three words of the second sentence of paragraph 1 of
    26.5.7.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.gslice.array.assign"> [lib.gslice.array.assign]</a> to "These assignment operators have"</li>
</ul>

<p>mask_array:</p>
<ul>
<li> Make the copy constructor and copy-assignment operator declarations
    public in the mask_array class template definition in 26.5.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.mask.array"> [lib.template.mask.array]</a> </li>
<li> remove the note in paragraph 2 of 26.5.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.mask.array"> [lib.template.mask.array]</a>
</li>
<li> remove the copy constructor declaration from 26.5.8.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.mask.array.cons"> [lib.mask.array.cons]</a>
</li>
<li> change paragraph 1 of 26.5.8.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.mask.array.cons"> [lib.mask.array.cons]</a> to read "This constructor is declared
    to be private.  This constructor need not be defined."</li>
<li> remove the first sentence of paragraph 1 of 26.5.8.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.mask.array.assign"> [lib.mask.array.assign]</a>
</li>
<li> Change the first three words of the second sentence of paragraph 1 of
    26.5.8.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.mask.array.assign"> [lib.mask.array.assign]</a> to "These assignment operators have"</li>
</ul>

<p>indirect_array:</p>
<ul>
<li>Make the copy constructor and copy-assignment operator declarations
    public in the indirect_array class definition in 26.5.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.indirect.array"> [lib.template.indirect.array]</a>
</li>
<li> remove the note in paragraph 2 of 26.5.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.template.indirect.array"> [lib.template.indirect.array]</a>
</li>
<li> remove the copy constructor declaration from 26.5.9.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.indirect.array.cons"> [lib.indirect.array.cons]</a>
</li>
<li> change the descriptive text in 26.5.9.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.indirect.array.cons"> [lib.indirect.array.cons]</a> to read "This constructor is
    declared to be private.  This constructor need not be defined."</li>
<li> remove the first sentence of paragraph 1 of 26.5.9.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.indirect.array.assign"> [lib.indirect.array.assign]</a>
</li>
<li> Change the first three words of the second sentence of paragraph 1 of
    26.5.9.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.indirect.array.assign"> [lib.indirect.array.assign]</a> to "These assignment operators have"</li>
</ul>
<p><i>[Proposed resolution was modified in Santa Cruz: explicitly make
copy constructor and copy assignment operators public, instead of
removing them.]</i></p>
<p><b>Rationale:</b></p>
<p>Keeping the valarray constructors private is untenable.  Merely
making valarray a friend of the helper classes isn't good enough,
because access to the copy constructor is checked in the user's
environment.</p>

<p>Making the assignment operator public is not strictly necessary to
solve this problem.  A majority of the LWG <i>(straw poll: 13-4)</i>
believed we should make the assignment operators public, in addition
to the copy constructors, for reasons of symmetry and user
expectation.</p>
<hr>
<a name="256"><h3>256.&nbsp;typo in 27.4.4.2, p17: copy_event does not exist</h3></a><p><b>Section:</b>&nbsp;27.4.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.members"> [lib.basic.ios.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;21 Aug 2000</p>
<p>
27.4.4.2, p17 says
</p>

<blockquote>
-17- Before copying any parts of rhs, calls each registered callback
pair (fn,index) as (*fn)(erase_event,*this,index). After all parts but
exceptions() have been replaced, calls each callback pair that was
copied from rhs as (*fn)(copy_event,*this,index). 
</blockquote>

<p>
The name copy_event isn't defined anywhere. The intended name was
copyfmt_event.
</p>
<p><b>Proposed resolution:</b></p>
<p>Replace copy_event with copyfmt_event in the named paragraph.</p>
<hr>
<a name="259"><h3>259.&nbsp;<tt>basic_string::operator[]</tt> and const correctness</h3></a><p><b>Section:</b>&nbsp;21.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.access"> [lib.string.access]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Chris Newton &nbsp; <b>Date:</b>&nbsp;27 Aug 2000</p>
<p>
<i>Paraphrased from a message that Chris Newton posted to comp.std.c++:</i>
</p>

<p>
The standard's description of <tt>basic_string&lt;&gt;::operator[]</tt>
seems to violate const correctness.
</p>

<p>
The standard (21.3.4/1) says that "If <tt>pos &lt; size()</tt>,
returns <tt>data()[pos]</tt>." The types don't work.  The
return value of <tt>data()</tt> is <tt>const charT*</tt>, but
<tt>operator[]</tt> has a non-const version whose return type is <tt>reference</tt>.
</p>
<p><b>Proposed resolution:</b></p>
<p>
In section 21.3.4, paragraph 1, change
"<tt>data()[<i>pos</i>]</tt>" to "<tt>*(begin() +
<i>pos</i>)</tt>".
</p>
<hr>
<a name="260"><h3>260.&nbsp;Inconsistent return type of <tt>istream_iterator::operator++(int)</tt>
</h3></a><p><b>Section:</b>&nbsp;24.5.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istream.iterator.ops"> [lib.istream.iterator.ops]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;27 Aug 2000</p>
<p>The synopsis of istream_iterator::operator++(int) in 24.5.1 shows
it as returning the iterator by value. 24.5.1.2, p5 shows the same
operator as returning the iterator by reference. That's incorrect
given the Effects clause below (since a temporary is returned). The
`&amp;' is probably just a typo.</p>
<p><b>Proposed resolution:</b></p>
<p>Change the declaration in 24.5.1.2, p5 from</p>
 <pre> istream_iterator&lt;T,charT,traits,Distance&gt;&amp; operator++(int);
 </pre>
<p>to</p>
 <pre> istream_iterator&lt;T,charT,traits,Distance&gt; operator++(int);
 </pre>
<p>(that is, remove the `&amp;').</p>
<hr>
<a name="261"><h3>261.&nbsp;Missing description of <tt>istream_iterator::operator!=</tt>
</h3></a><p><b>Section:</b>&nbsp;24.5.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istream.iterator.ops"> [lib.istream.iterator.ops]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;27 Aug 2000</p>
<p>
24.5.1, p3 lists the synopsis for
</p>

<pre>   template &lt;class T, class charT, class traits, class Distance&gt;
        bool operator!=(const istream_iterator&lt;T,charT,traits,Distance&gt;&amp; x,
                        const istream_iterator&lt;T,charT,traits,Distance&gt;&amp; y);
</pre>

<p>
but there is no description of what the operator does (i.e., no Effects
or Returns clause) in 24.5.1.2.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add paragraph 7 to the end of section 24.5.1.2 with the following text:
</p>

<pre>   template &lt;class T, class charT, class traits, class Distance&gt;
        bool operator!=(const istream_iterator&lt;T,charT,traits,Distance&gt;&amp; x,
                        const istream_iterator&lt;T,charT,traits,Distance&gt;&amp; y);
</pre>

<p>-7- Returns: !(x == y).</p>
<hr>
<a name="262"><h3>262.&nbsp;Bitmask operator ~ specified incorrectly</h3></a><p><b>Section:</b>&nbsp;17.3.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.bitmask.types"> [lib.bitmask.types]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;03 Sep 2000</p>
<p>
The ~ operation should be applied after the cast to int_type.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 17.3.2.1.2 [lib.bitmask.types] operator~ from:
</p>

<pre>   bitmask operator~ ( bitmask X )
     { return static_cast&lt; bitmask&gt;(static_cast&lt;int_type&gt;(~ X)); }
</pre>

<p>
to:
</p>

<pre>   bitmask operator~ ( bitmask X )
     { return static_cast&lt; bitmask&gt;(~static_cast&lt;int_type&gt;(X)); }
</pre>
<hr>
<a name="263"><h3>263.&nbsp;Severe restriction on <tt>basic_string</tt> reference counting</h3></a><p><b>Section:</b>&nbsp;21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Kevlin Henney&nbsp; <b>Date:</b>&nbsp;04 Sep 2000</p>
<p>
The note in paragraph 6 suggests that the invalidation rules for
references, pointers, and iterators in paragraph 5 permit a reference-
counted implementation (actually, according to paragraph 6, they permit
a "reference counted implementation", but this is a minor editorial fix).
</p>

<p>
However, the last sub-bullet is so worded as to make a reference-counted
implementation unviable. In the following example none of the
conditions for iterator invalidation are satisfied:
</p>

<pre>    // first example: "*******************" should be printed twice
    string original = "some arbitrary text", copy = original;
    const string &amp; alias = original;

    string::const_iterator i = alias.begin(), e = alias.end();
    for(string::iterator j = original.begin(); j != original.end(); ++j)
        *j = '*';
    while(i != e)
        cout &lt;&lt; *i++;
    cout &lt;&lt; endl;
    cout &lt;&lt; original &lt;&lt; endl;
</pre>

<p>
Similarly, in the following example:
</p>

<pre>    // second example: "some arbitrary text" should be printed out
    string original = "some arbitrary text", copy = original;
    const string &amp; alias = original;

    string::const_iterator i = alias.begin();
    original.begin();
    while(i != alias.end())
        cout &lt;&lt; *i++;
</pre>

<p>
I have tested this on three string implementations, two of which were
reference counted. The reference-counted implementations gave
"surprising behavior" because they invalidated iterators on
the first call to non-const begin since construction. The current
wording does not permit such invalidation because it does not take
into account the first call since construction, only the first call
since various member and non-member function calls.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the following sentence in 21.3 paragraph 5 from
</p>

<blockquote>
    Subsequent to any of the above uses except the forms of insert() and
    erase() which return iterators, the first call to non-const member
    functions operator[](), at(), begin(), rbegin(), end(), or rend().
</blockquote>

<p>to</p>

<blockquote>
    Following construction or any of the above uses, except the forms of
    insert() and erase() that return iterators, the first call to non-
    const member functions operator[](), at(), begin(), rbegin(), end(),
    or rend().
</blockquote>
<hr>
<a name="264"></a><h3><a name="264">264.&nbsp;Associative container <tt>insert(i, j)</tt> complexity requirements are not feasible.</a></h3><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;John Potter&nbsp; <b>Date:</b>&nbsp;07 Sep 2000</p>
<p>
Table 69 requires linear time if [i, j) is sorted.  Sorted is necessary but not sufficient.
Consider inserting a sorted range of even integers into a set&lt;int&gt; containing the odd
integers in the same range.
</p>

<p><i>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#102">102</a></i></p>
<p><b>Proposed resolution:</b></p>
<p>
In Table 69, in section 23.1.2, change the complexity clause for
insertion of a range from "N log(size() + N) (N is the distance
from i to j) in general; linear if [i, j) is sorted according to
value_comp()" to "N log(size() + N), where N is the distance
from i to j".
</p>

<p><i>[Copenhagen: Minor fix in proposed resolution: fixed unbalanced
parens in the revised wording.]</i></p>

<p><b>Rationale:</b></p>
<p>
Testing for valid insertions could be less efficient than simply
inserting the elements when the range is not both sorted and between
two adjacent existing elements; this could be a QOI issue.
</p>

<p> 
The LWG considered two other options: (a) specifying that the
complexity was linear if [i, j) is sorted according to value_comp()
and between two adjacent existing elements; or (b) changing to
Klog(size() + N) + (N - K) (N is the distance from i to j and K is the
number of elements which do not insert immediately after the previous
element from [i, j) including the first).  The LWG felt that, since
we can't guarantee linear time complexity whenever the range to be
inserted is sorted, it's more trouble than it's worth to say that it's
linear in some special cases.
</p>
<hr>
<a name="265"><h3>265.&nbsp;std::pair::pair() effects overly restrictive</h3></a><p><b>Section:</b>&nbsp;20.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.pairs"> [lib.pairs]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;11 Sep 2000</p>
<p>
I don't see any requirements on the types of the elements of the
std::pair container in 20.2.2. From the descriptions of the member
functions it appears that they must at least satisfy the requirements of
20.1.3 [lib.copyconstructible] and 20.1.4 [lib.default.con.req], and in
the case of the [in]equality operators also the requirements of 20.1.1
[lib.equalitycomparable] and 20.1.2 [lib.lessthancomparable].
</p>

<p>
I believe that the the CopyConstructible requirement is unnecessary in
the case of 20.2.2, p2.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the Effects clause in 20.2.2, p2 from</p>

<blockquote>
-2- <b>Effects</b>: Initializes its members as if implemented: <tt> pair() :
first(T1()), second(T2()) {} </tt>
</blockquote>

<p>to</p>

<blockquote>
-2- <b>Effects</b>: Initializes its members as if implemented: <tt> pair() :
first(), second() {} </tt>
</blockquote>
<p><b>Rationale:</b></p>
<p>The existing specification of pair's constructor appears to be a
historical artifact: there was concern that pair's members be properly
zero-initialized when they are built-in types.  At one time there was
uncertainty about whether they would be zero-initialized if the
default constructor was written the obvious way.  This has been
clarified by core issue 178, and there is no longer any doubt that
the straightforward implementation is correct.</p>
<hr>
<a name="266"><h3>266.&nbsp;bad_exception::~bad_exception() missing Effects clause</h3></a><p><b>Section:</b>&nbsp;18.7.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.bad.exception"> [lib.bad.exception]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;24 Sep 2000</p>
<p>
The synopsis for std::bad_exception lists the function ~bad_exception()
but there is no description of what the function does (the Effects
clause is missing).
</p>
<p><b>Proposed resolution:</b></p>
<p>
Remove the destructor from the class synopses of 
<tt>bad_alloc</tt> (<font color="red">18.4.2.1</font>),
<tt>bad_cast</tt> (18.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.alloc.errors"> [lib.alloc.errors]</a>),
<tt>bad_typeid</tt> (<font color="red">18.5.3</font>),
and <tt>bad_exception</tt> (18.7.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.bad.exception"> [lib.bad.exception]</a>).
</p>
<p><b>Rationale:</b></p>
<p>
This is a general problem with the exception classes in clause 18. 
The proposed resolution is to remove the destructors from the class
synopses, rather than to document the destructors' behavior, because
removing them is more consistent with how exception classes are
described in clause 19.
</p>
<hr>
<a name="268"><h3>268.&nbsp;Typo in locale synopsis</h3></a><p><b>Section:</b>&nbsp;22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;5 Oct 2000</p>
<p>The synopsis of the class std::locale in 22.1.1 contains two typos:
the semicolons after the declarations of the default ctor
locale::locale() and the copy ctor locale::locale(const locale&amp;)
are missing.</p>
<p><b>Proposed resolution:</b></p>
<p>Add the missing semicolons, i.e., change</p>

<pre>    //  construct/copy/destroy:
        locale() throw()
        locale(const locale&amp; other) throw()
</pre>

<p>in the synopsis in 22.1.1 to</p>

<pre>    //  construct/copy/destroy:
        locale() throw();
        locale(const locale&amp; other) throw();
</pre>
<hr>
<a name="270"><h3>270.&nbsp;Binary search requirements overly strict</h3></a><p><b>Section:</b>&nbsp;25.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.binary.search"> [lib.alg.binary.search]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;18 Oct 2000</p>
<p>
Each of the four binary search algorithms (lower_bound, upper_bound,
equal_range, binary_search) has a form that allows the user to pass a
comparison function object.  According to 25.3, paragraph 2, that
comparison function object has to be a strict weak ordering.
</p>

<p>
This requirement is slightly too strict.  Suppose we are searching
through a sequence containing objects of type X, where X is some
large record with an integer key.  We might reasonably want to look
up a record by key, in which case we would want to write something
like this:
</p>
<pre>    struct key_comp {
      bool operator()(const X&amp; x, int n) const {
        return x.key() &lt; n;
      }
    }

    std::lower_bound(first, last, 47, key_comp());
</pre>

<p>
key_comp is not a strict weak ordering, but there is no reason to
prohibit its use in lower_bound.
</p>

<p>
There's no difficulty in implementing lower_bound so that it allows
the use of something like key_comp.  (It will probably work unless an
implementor takes special pains to forbid it.)  What's difficult is
formulating language in the standard to specify what kind of
comparison function is acceptable.  We need a notion that's slightly
more general than that of a strict weak ordering, one that can encompass
a comparison function that involves different types.  Expressing that
notion may be complicated.
</p>

<p><i>Additional questions raised at the Toronto meeting:</i></p>
<ul>
<li> Do we really want to specify what ordering the implementor must
     use when calling the function object?  The standard gives 
     specific expressions when describing these algorithms, but it also
     says that other expressions (with different argument order) are
     equivalent.</li>
<li> If we are specifying ordering, note that the standard uses both
     orderings when describing <tt>equal_range</tt>.</li>
<li> Are we talking about requiring these algorithms to work properly
     when passed a binary function object whose two argument types
     are not the same, or are we talking about requirements when
     they are passed a binary function object with several overloaded
     versions of <tt>operator()</tt>?</li>
<li> The definition of a strict weak ordering does not appear to give
     any guidance on issues of overloading; it only discusses expressions,
     and all of the values in these expressions are of the same type.
     Some clarification would seem to be in order.</li>
</ul>

<p><i>Additional discussion from Copenhagen:</i></p>
<ul>
<li>It was generally agreed that there is a real defect here: if
the predicate is merely required to be a Strict Weak Ordering, then
it's possible to pass in a function object with an overloaded
operator(), where the version that's actually called does something
completely inappropriate.  (Such as returning a random value.)</li>

<li>An alternative formulation was presented in a paper distributed by
David Abrahams at the meeting, "Binary Search with Heterogeneous
Comparison", J16-01/0027 = WG21 N1313: Instead of viewing the
predicate as a Strict Weak Ordering acting on a sorted sequence, view
the predicate/value pair as something that partitions a sequence.
This is almost equivalent to saying that we should view binary search
as if we are given a unary predicate and a sequence, such that f(*p)
is true for all p below a specific point and false for all p above it.
The proposed resolution is based on that alternative formulation.</li>
</ul>
<p><b>Proposed resolution:</b></p>

<p>Change 25.3 [lib.alg.sorting] paragraph 3 from:</p>

<blockquote>
  3 For all algorithms that take Compare, there is a version that uses
  operator&lt; instead. That is, comp(*i, *j) != false defaults to *i &lt;
  *j != false. For the algorithms to work correctly, comp has to
  induce a strict weak ordering on the values.
</blockquote>

<p>to:</p>

<blockquote>
  3 For all algorithms that take Compare, there is a version that uses
  operator&lt; instead. That is, comp(*i, *j) != false defaults to *i
  &lt; *j != false. For algorithms other than those described in
  lib.alg.binary.search (25.3.3) to work correctly, comp has to induce
  a strict weak ordering on the values.
</blockquote>

<p>Add the following paragraph after 25.3 [lib.alg.sorting] paragraph 5:</p>

<blockquote>
  -6- A sequence [start, finish) is partitioned with respect to an
  expression f(e) if there exists an integer n such that
  for all 0 &lt;= i &lt; distance(start, finish), f(*(begin+i)) is true if
  and only if i &lt; n.
</blockquote>

<p>Change 25.3.3 [lib.alg.binary.search] paragraph 1 from:</p>

<blockquote>
  -1- All of the algorithms in this section are versions of binary
   search and assume that the sequence being searched is in order
   according to the implied or explicit comparison function. They work
   on non-random access iterators minimizing the number of
   comparisons, which will be logarithmic for all types of
   iterators. They are especially appropriate for random access
   iterators, because these algorithms do a logarithmic number of
   steps through the data structure. For non-random access iterators
   they execute a linear number of steps.
</blockquote>

<p>to:</p>

<blockquote>
   -1- All of the algorithms in this section are versions of binary
    search and assume that the sequence being searched is partitioned
    with respect to an expression formed by binding the search key to
    an argument of the implied or explicit comparison function. They
    work on non-random access iterators minimizing the number of
    comparisons, which will be logarithmic for all types of
    iterators. They are especially appropriate for random access
    iterators, because these algorithms do a logarithmic number of
    steps through the data structure. For non-random access iterators
    they execute a linear number of steps.
</blockquote>

<p>Change 25.3.3.1 [lib.lower.bound] paragraph 1 from:</p>

<blockquote>
   -1- Requires: Type T is LessThanComparable
    (lib.lessthancomparable). 
</blockquote>

<p>to:</p>

<blockquote>
   -1- Requires: The elements e of [first, last) are partitioned with
   respect to the expression e &lt; value or comp(e, value)
</blockquote>


<p>Remove 25.3.3.1 [lib.lower.bound] paragraph 2:</p>

<blockquote>
   -2- Effects: Finds the first position into which value can be
    inserted without violating the ordering. 
</blockquote>

<p>Change 25.3.3.2 [lib.upper.bound] paragraph 1 from:</p>

<blockquote>
  -1- Requires: Type T is LessThanComparable (lib.lessthancomparable).
</blockquote>

<p>to:</p>

<blockquote>
   -1- Requires: The elements e of [first, last) are partitioned with
   respect to the expression !(value &lt; e) or !comp(value, e)
</blockquote>

<p>Remove 25.3.3.2 [lib.upper.bound] paragraph 2:</p>

<blockquote>
   -2- Effects: Finds the furthermost position into which value can be
    inserted without violating the ordering.
</blockquote>

<p>Change 25.3.3.3 [lib.equal.range] paragraph 1 from:</p>

<blockquote>
   -1- Requires: Type T is LessThanComparable
    (lib.lessthancomparable).
</blockquote>

<p>to:</p>

<blockquote>
   -1- Requires: The elements e of [first, last) are partitioned with
   respect to the expressions e &lt; value and !(value &lt; e) or
   comp(e, value) and !comp(value, e).  Also, for all elements e of
   [first, last), e &lt; value implies !(value &lt; e) or comp(e,
   value) implies !comp(value, e)
</blockquote>

<p>Change 25.3.3.3 [lib.equal.range] paragraph 2 from:</p>

<blockquote>
   -2- Effects: Finds the largest subrange [i, j) such that the value
    can be inserted at any iterator k in it without violating the
    ordering. k satisfies the corresponding conditions: !(*k &lt; value)
    &amp;&amp; !(value &lt; *k) or comp(*k, value) == false &amp;&amp; comp(value, *k) ==
    false.
</blockquote>

<p>to:</p>

<pre>   -2- Returns: 
         make_pair(lower_bound(first, last, value),
                   upper_bound(first, last, value))
       or
         make_pair(lower_bound(first, last, value, comp),
                   upper_bound(first, last, value, comp))
</pre>

<p>Change 25.3.3.3 [lib.binary.search] paragraph 1 from:</p>

<blockquote>
   -1- Requires: Type T is LessThanComparable
    (lib.lessthancomparable).
</blockquote>

<p>to:</p>

<blockquote>
   -1- Requires: The elements e of [first, last) are partitioned with
   respect to the expressions e &lt; value and !(value &lt; e) or comp(e,
   value) and !comp(value, e). Also, for all elements e of [first,
   last), e &lt; value implies !(value &lt; e) or comp(e, value) implies
   !comp(value, e)
</blockquote>

<p><i>[Copenhagen: Dave Abrahams provided this wording]</i></p>

<p><i>[Redmond: Minor changes in wording.  (Removed "non-negative", and
changed the "other than those described in" wording.) Also, the LWG
decided to accept the "optional" part.]</i></p>

<p><b>Rationale:</b></p>
<p>The proposed resolution reinterprets binary search. Instead of
thinking about searching for a value in a sorted range, we view that
as an important special case of a more general algorithm: searching
for the partition point in a partitioned range.</p>

<p>We also add a guarantee that the old wording did not: we ensure
that the upper bound is no earlier than the lower bound, that
the pair returned by equal_range is a valid range, and that the first
part of that pair is the lower bound.</p>
<hr>
<a name="271"><h3>271.&nbsp;basic_iostream missing typedefs</h3></a><p><b>Section:</b>&nbsp;27.6.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostreamclass"> [lib.iostreamclass]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;02 Nov 2000</p>
<p>
Class template basic_iostream has no typedefs.  The typedefs it
inherits from its base classes can't be used, since (for example)
basic_iostream&lt;T&gt;::traits_type is ambiguous.
</p>
<p><b>Proposed resolution:</b></p>

<p>Add the following to basic_iostream's class synopsis in 
27.6.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostreamclass"> [lib.iostreamclass]</a>, immediately after <tt>public</tt>:</p>

<pre>  // types:
  typedef charT                     char_type;
  typedef typename traits::int_type int_type;
  typedef typename traits::pos_type pos_type;
  typedef typename traits::off_type off_type;
  typedef traits                    traits_type;
</pre>
<hr>
<a name="272"><h3>272.&nbsp;Missing parentheses around subexpression</h3></a><p><b>Section:</b>&nbsp;27.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostate.flags"> [lib.iostate.flags]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;02 Nov 2000</p>
<p>
27.4.4.3, p4 says about the postcondition of the function: If
rdbuf()!=0 then state == rdstate(); otherwise
rdstate()==state|ios_base::badbit.
</p>

<p>
The expression on the right-hand-side of the operator==() needs to be
parenthesized in order for the whole expression to ever evaluate to
anything but non-zero.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add parentheses like so: rdstate()==(state|ios_base::badbit).
</p>
<hr>
<a name="273"><h3>273.&nbsp;Missing ios_base qualification on members of a dependent class</h3></a><p><b>Section:</b>&nbsp;27 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.input.output"> [lib.input.output]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;02 Nov 2000</p>
<p>27.5.2.4.2, p4, and 27.8.1.6, p2, 27.8.1.7, p3, 27.8.1.9, p2,
27.8.1.10, p3 refer to in and/or out w/o ios_base:: qualification.
That's incorrect since the names are members of a dependent base
class (14.6.2 [temp.dep]) and thus not visible.</p>
<p><b>Proposed resolution:</b></p>
<p>Qualify the names with the name of the class of which they are
members, i.e., ios_base.</p>
<hr>
<a name="274"><h3>274.&nbsp;a missing/impossible allocator requirement</h3></a><p><b>Section:</b>&nbsp;20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;02 Nov 2000</p>
<p>
I see that table 31 in 20.1.5, p3 allows T in std::allocator&lt;T&gt; to be of
any type. But the synopsis in 20.4.1 calls for allocator&lt;&gt;::address() to
be overloaded on reference and const_reference, which is ill-formed for
all T = const U. In other words, this won't work:
</p>

<p>
template class std::allocator&lt;const int&gt;;
</p>

<p>
The obvious solution is to disallow specializations of allocators on
const types. However, while containers' elements are required to be
assignable (which rules out specializations on const T's), I think that
allocators might perhaps be potentially useful for const values in other
contexts. So if allocators are to allow const types a partial
specialization of std::allocator&lt;const T&gt; would probably have to be
provided.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the text in row 1, column 2 of table 32 in 20.1.5, p3 from</p>

    <blockquote>
    any type
    </blockquote>

<p>to</p>
    <blockquote>
    any non-const, non-reference type
    </blockquote>

<p><i>[Redmond: previous proposed resolution was "any non-const,
non-volatile, non-reference type".  Got rid of the "non-volatile".]</i></p>

<p><b>Rationale:</b></p>
<p>
Two resolutions were originally proposed: one that partially
specialized std::allocator for const types, and one that said an
allocator's value type may not be const.  The LWG chose the second.
The first wouldn't be appropriate, because allocators are intended for
use by containers, and const value types don't work in containers.
Encouraging the use of allocators with const value types would only
lead to unsafe code.
</p>
<p>
The original text for proposed resolution 2 was modified so that it
also forbids volatile types and reference types.
</p>

<p><i>[Curaçao: LWG double checked and believes volatile is correctly
excluded from the PR.]</i></p>

<hr>
<a name="275"><h3>275.&nbsp;Wrong type in num_get::get() overloads</h3></a><p><b>Section:</b>&nbsp;22.2.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.members"> [lib.facet.num.get.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;02 Nov 2000</p>
<p>
In 22.2.2.1.1, we have a list of overloads for num_get&lt;&gt;::get().
There are eight overloads, all of which are identical except for the
last parameter.  The overloads are: 
</p>
<ul>
<li> long&amp; </li>
<li> unsigned short&amp; </li>
<li> unsigned int&amp; </li>
<li> unsigned long&amp; </li>
<li> short&amp; </li>
<li> double&amp; </li>
<li> long double&amp; </li>
<li> void*&amp; </li>
</ul>

<p>
There is a similar list, in 22.2.2.1.2, of overloads for
num_get&lt;&gt;::do_get().  In this list, the last parameter has
the types: 
</p>
<ul>
<li> long&amp; </li>
<li> unsigned short&amp; </li>
<li> unsigned int&amp; </li>
<li> unsigned long&amp; </li>
<li> float&amp; </li>
<li> double&amp; </li>
<li> long double&amp; </li>
<li> void*&amp; </li>
</ul>

<p>
These two lists are not identical.  They should be, since
<tt>get</tt> is supposed to call <tt>do_get</tt> with exactly
the arguments it was given.
</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.members"> [lib.facet.num.get.members]</a>, change</p>
<pre>  iter_type get(iter_type in, iter_type end, ios_base&amp; str,
                ios_base::iostate&amp; err, short&amp; val) const;
</pre>
<p>to</p>
<pre>  iter_type get(iter_type in, iter_type end, ios_base&amp; str,
                ios_base::iostate&amp; err, float&amp; val) const;
</pre>
<hr>
<a name="276"></a><h3><a name="276">276.&nbsp;Assignable requirement for container value type overly strict</a></h3><p><b>Section:</b>&nbsp;23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Peter Dimov&nbsp; <b>Date:</b>&nbsp;07 Nov 2000</p>
<p>
23.1/3 states that the objects stored in a container must be
Assignable.  23.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map"> [lib.map]</a>, paragraph 2,
states that map satisfies all requirements for a container, while in
the same time defining value_type as pair&lt;const Key, T&gt; - a type
that is not Assignable.
</p>

<p>
It should be noted that there exists a valid and non-contradictory
interpretation of the current text. The wording in 23.1/3 avoids 
mentioning value_type, referring instead to "objects stored in a
container." One might argue that map does not store objects of
type map::value_type, but of map::mapped_type instead, and that the
Assignable requirement applies to map::mapped_type, not
map::value_type.
</p>

<p>
However, this makes map a special case (other containers store objects of
type value_type) and the Assignable requirement is needlessly restrictive in
general.
</p>

<p>
For example, the proposed resolution of active library issue 
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#103">103</a> is to make set::iterator a constant iterator; this
means that no set operations can exploit the fact that the stored
objects are Assignable.
</p>

<p>
This is related to, but slightly broader than, closed issue
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#140">140</a>.
</p>
<p><b>Proposed resolution:</b></p>
<p>23.1/3: Strike the trailing part of the sentence:</p>
    <blockquote>
    , and the additional requirements of Assignable types from 23.1/3
    </blockquote>
<p>so that it reads:</p>
    <blockquote>
    -3- The type of objects stored in these components must meet the 
    requirements of CopyConstructible types (lib.copyconstructible).
    </blockquote>

<p>23.1/4: Modify to make clear that this requirement is not for all 
containers.  Change to:</p>

<blockquote>
-4- Table 64 defines the Assignable requirement.  Some containers 
require this property of the types to be stored in the container.  T is 
the type used to instantiate the container. t is a value of T, and u is 
a value of (possibly const) T.
</blockquote>

<p>23.1, Table 65: in the first row, change "T is Assignable" to "T is
CopyConstructible".</p>

<p>23.2.1/2: Add sentence for Assignable requirement.  Change to:</p>

<blockquote>
-2- A deque satisfies all of the requirements of a container and of a 
reversible container (given in tables in lib.container.requirements) and 
of a sequence, including the optional sequence requirements 
(lib.sequence.reqmts).  In addition to the requirements on the stored 
object described in 23.1[lib.container.requirements], the stored object 
must also meet the requirements of Assignable.  Descriptions are 
provided here only for operations on deque that are not described in one 
of these tables or for operations where there is additional semantic 
information.
</blockquote>

<p>23.2.2/2:  Add Assignable requirement to specific methods of list.  
Change to:</p>

<blockquote>
<p>-2- A list satisfies all of the requirements of a container and of a 
reversible container (given in two tables in lib.container.requirements) 
and of a sequence, including most of the the optional sequence 
requirements (lib.sequence.reqmts). The exceptions are the operator[] 
and at member functions, which are not provided. 

[Footnote: These member functions are only provided by containers whose 
iterators are random access iterators. --- end foonote]
</p>

<p>list does not require the stored type T to be Assignable unless the 
following methods are instantiated:

[Footnote: Implementors are permitted but not required to take advantage 
of T's Assignable properties for these methods. -- end foonote]
</p>
<pre>     list&lt;T,Allocator&gt;&amp; operator=(const list&lt;T,Allocator&gt;&amp;  x );
     template &lt;class InputIterator&gt;
       void assign(InputIterator first, InputIterator last);
     void assign(size_type n, const T&amp; t);
</pre>


<p>Descriptions are provided here only for operations on list that are not 
described in one of these tables or for operations where there is 
additional semantic information.</p>
</blockquote>

<p>23.2.4/2:   Add sentence for Assignable requirement.  Change to:</p>

<blockquote>
-2- A vector satisfies all of the requirements of a container and of a 
reversible container (given in two tables in lib.container.requirements) 
and of a sequence, including most of the optional sequence requirements 
(lib.sequence.reqmts). The exceptions are the push_front and pop_front 
member functions, which are not provided.  In addition to the 
requirements on the stored object described in 
23.1[lib.container.requirements], the stored object must also meet the 
requirements of Assignable.  Descriptions are provided here only for 
operations on vector that are not described in one of these tables or 
for operations where there is additional semantic information.
</blockquote>
<p><b>Rationale:</b></p>
<p>list, set, multiset, map, multimap are able to store non-Assignables.
However, there is some concern about <tt>list&lt;T&gt;</tt>:
although in general there's no reason for T to be Assignable, some
implementations of the member functions <tt>operator=</tt> and
<tt>assign</tt> do rely on that requirement.  The LWG does not want
to forbid such implementations.</p>

<p>Note that the type stored in a standard container must still satisfy
the requirements of the container's allocator; this rules out, for
example, such types as "const int".  See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#274">274</a>
for more details.
</p>

<p>In principle we could also relax the "Assignable" requirement for
individual <tt>vector</tt> member functions, such as
<tt>push_back</tt>.  However, the LWG did not see great value in such
selective relaxation.  Doing so would remove implementors' freedom to
implement <tt>vector::push_back</tt> in terms of
<tt>vector::insert</tt>.</p>

<hr>
<a name="278"><h3>278.&nbsp;What does iterator validity mean?</h3></a><p><b>Section:</b>&nbsp;23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;P.J. Plauger&nbsp; <b>Date:</b>&nbsp;27 Nov 2000</p>
<p>
Section 23.2.2.4 [lib.list.ops] states that
</p>
<pre>  void splice(iterator position, list&lt;T, Allocator&gt;&amp; x);
</pre>
<p>
<i>invalidates</i> all iterators and references to list <tt>x</tt>.
</p>

<p>
But what does the C++ Standard mean by "invalidate"?  You
can still dereference the iterator to a spliced list element, but
you'd better not use it to delimit a range within the original
list. For the latter operation, it has definitely lost some of its
validity.
</p>

<p>
If we accept the proposed resolution to issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#250">250</a>,
then we'd better clarify that a "valid" iterator need no
longer designate an element within the same container as it once did.
We then have to clarify what we mean by invalidating a past-the-end
iterator, as when a vector or string grows by reallocation. Clearly,
such an iterator has a different kind of validity. Perhaps we should
introduce separate terms for the two kinds of "validity."
</p>
<p><b>Proposed resolution:</b></p>
<p>Add the following text to the end of section 24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>,
after paragraph 5:</p>
<blockquote>
An <i>invalid</i> iterator is an iterator that may be
singular. [Footnote: This definition applies to pointers, since
pointers are iterators. The effect of dereferencing an iterator that
has been invalidated is undefined.]
</blockquote>

<p><i>[post-Copenhagen: Matt provided wording.]</i></p>

<p><i>[Redmond: General agreement with the intent, some objections to
the wording.  Dave provided new wording.]</i></p>
<p><b>Rationale:</b></p>
<p>This resolution simply defines a term that the Standard uses but
  never defines, "invalid", in terms of a term that is defined,
  "singular".</p>

<p>Why do we say "may be singular", instead of "is singular"?  That's
  becuase a valid iterator is one that is known to be nonsingular.
  Invalidating an iterator means changing it in such a way that it's
  no longer known to be nonsingular.  An example: inserting an
  element into the middle of a vector is correctly said to invalidate
  all iterators pointing into the vector.  That doesn't necessarily
  mean they all become singular.</p>
<hr>
<a name="280"><h3>280.&nbsp;Comparison of reverse_iterator to const reverse_iterator</h3></a><p><b>Section:</b>&nbsp;24.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iterators"> [lib.reverse.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Cleary&nbsp; <b>Date:</b>&nbsp;27 Nov 2000</p>
<p>
This came from an email from Steve Cleary to Fergus in reference to
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#179">179</a>. The library working group briefly discussed
this in Toronto and believed it should be a separate issue.  There was
also some reservations about whether this was a worthwhile problem to
fix.
</p>

<p>
Steve said: "Fixing reverse_iterator. std::reverse_iterator can
(and should) be changed to preserve these additional
requirements." He also said in email that it can be done without
breaking user's code: "If you take a look at my suggested
solution, reverse_iterator doesn't have to take two parameters; there
is no danger of breaking existing code, except someone taking the
address of one of the reverse_iterator global operator functions, and
I have to doubt if anyone has ever done that. . .  <i>But</i>, just in
case they have, you can leave the old global functions in as well --
they won't interfere with the two-template-argument functions.  With
that, I don't see how <i>any</i> user code could break."
</p>
<p><b>Proposed resolution:</b></p>
<p>
<b>Section:</b> 24.4.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iterator"> [lib.reverse.iterator]</a>
add/change the following declarations:</p>
<pre>  A) Add a templated assignment operator, after the same manner
        as the templated copy constructor, i.e.:

  template &lt; class U &gt;
  reverse_iterator &lt; Iterator &gt;&amp; operator=(const reverse_iterator&lt; U &gt;&amp; u);

  B) Make all global functions (except the operator+) have
  two template parameters instead of one, that is, for
  operator ==, !=, &lt;, &gt;, &lt;=, &gt;=, - replace:

       template &lt; class Iterator &gt;
       typename reverse_iterator&lt; Iterator &gt;::difference_type operator-(
                 const reverse_iterator&lt; Iterator &gt;&amp; x,
                 const reverse_iterator&lt; Iterator &gt;&amp; y);

  with:

      template &lt; class Iterator1, class Iterator2 &gt;
      typename reverse_iterator &lt; Iterator1 &gt;::difference_type operator-(
                 const reverse_iterator &lt; Iterator1 &gt; &amp; x,
                 const reverse_iterator &lt; Iterator2 &gt; &amp; y);
</pre>
<p>
Also make the addition/changes for these signatures in 
24.4.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.ops"> [lib.reverse.iter.ops]</a>.
</p>

<p><i>[
Copenhagen: The LWG is concerned that the proposed resolution 
introduces new overloads.  Experience shows that introducing
overloads is always risky, and that it would be inappropriate to
make this change without implementation experience.  It may be
desirable to provide this feature in a different way.
]</i></p>

<p><i>[
Lillehammer: We now have implementation experience, and agree that
this solution is safe and correct.
]</i></p>

<hr>
<a name="281"><h3>281.&nbsp;std::min() and max() requirements overly restrictive</h3></a><p><b>Section:</b>&nbsp;25.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.min.max"> [lib.alg.min.max]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;02 Dec 2000</p>
<p>The requirements in 25.3.7, p1 and 4 call for T to satisfy the
requirements of <tt>LessThanComparable</tt> (20.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.lessthancomparable"> [lib.lessthancomparable]</a>)
and <tt>CopyConstructible</tt> (20.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.copyconstructible"> [lib.copyconstructible]</a>).
Since the functions take and return their arguments and result by
const reference, I believe the <tt>CopyConstructible</tt> requirement
is unnecessary.
</p>
<p><b>Proposed resolution:</b></p>
<p>Remove the <tt>CopyConstructible</tt> requirement. Specifically, replace
25.3.7, p1 with</p>
<p><b>-1- Requires:</b> Type T is <tt>LessThanComparable</tt> 
(20.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.lessthancomparable"> [lib.lessthancomparable]</a>).
</p>
<p>and replace 25.3.7, p4 with</p>
<p><b>-4- Requires:</b> Type T is <tt>LessThanComparable</tt> 
(20.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.lessthancomparable"> [lib.lessthancomparable]</a>).
</p>
<hr>
<a name="282"><h3>282.&nbsp;What types does numpunct grouping refer to?</h3></a><p><b>Section:</b>&nbsp;22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;5 Dec 2000</p>
<p>
Paragraph 16 mistakenly singles out integral types for inserting 
thousands_sep() characters.  This conflicts with the syntax for floating 
point numbers described under 22.2.3.1/2.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change paragraph 16 from:</p>

<blockquote>
For integral types, punct.thousands_sep() characters are inserted into 
the sequence as determined by the value returned by punct.do_grouping() 
using the method described in 22.2.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.numpunct.virtuals"> [lib.facet.numpunct.virtuals]</a>.
</blockquote>

<p>To:</p>

<blockquote>
For arithmetic types, punct.thousands_sep() characters are inserted into 
the sequence as determined by the value returned by punct.do_grouping() 
using the method described in 22.2.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.numpunct.virtuals"> [lib.facet.numpunct.virtuals]</a>.
</blockquote>

<p><i>[
Copenhagen: Opinions were divided about whether this is actually an
inconsistency, but at best it seems to have been unintentional.  This
is only an issue for floating-point output: The standard is
unambiguous that implementations must parse thousands_sep characters
when performing floating-point.  The standard is also unambiguous that
this requirement does not apply to the "C" locale.
]</i></p>

<p><i>[
A survey of existing practice is needed; it is believed that some
implementations do insert thousands_sep characters for floating-point
output and others fail to insert thousands_sep characters for 
floating-point input even though this is unambiguously required by the
standard.
]</i></p>

<p><i>[Post-Curaçao: the above proposed resolution is the consensus of
Howard, Bill, Pete, Benjamin, Nathan, Dietmar, Boris, and Martin.]</i></p>

<hr>
<a name="283"><h3>283.&nbsp;std::replace() requirement incorrect/insufficient</h3></a><p><b>Section:</b>&nbsp;25.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.replace"> [lib.alg.replace]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;15 Dec 2000</p>
<p>
(revision of the further discussion)
There are a number of problems with the requires clauses for the
algorithms in 25.1 and 25.2. The requires clause of each algorithm
should describe the necessary and sufficient requirements on the inputs
to the algorithm such that the algorithm compiles and runs properly.
Many of the requires clauses fail to do this. Here is a summary of the kinds
of mistakes:
</p>

<ol>
<li>
Use of EqualityComparable, which only puts requirements on a single
type, when in fact an equality operator is required between two
different types, typically either T and the iterator's value type
or between the value types of two different iterators.
</li>
<li>
Use of Assignable for T when in fact what was needed is Assignable
for the value_type of the iterator, and convertability from T to the
value_type of the iterator. Or for output iterators, the requirement
should be that T is writable to the iterator (output iterators do
not have value types).
</li>
</ol>

<p>
Here is the list of algorithms that contain mistakes:
</p>

<ul>
<li>25.1.2 std::find</li>
<li>25.1.6 std::count</li>
<li>25.1.8 std::equal</li>
<li>25.1.9 std::search, std::search_n</li>
<li>25.2.4 std::replace, std::replace_copy</li>
<li>25.2.5 std::fill</li>
<li>25.2.7 std::remove, std::remove_copy</li>
</ul>

<p>
Also, in the requirements for EqualityComparable, the requirement that
the operator be defined for const objects is lacking.
</p>

<p><b>Proposed resolution:</b></p>

<p>20.1.1 Change p1 from</p>

<p>In Table 28, <tt>T</tt> is a type to be supplied by a C++ program
instantiating a template, <tt>a</tt>, <tt>b</tt>, and <tt>c</tt> are
values of type <tt>T</tt>.
</p>

<p>to</p>

<p>
In Table 28, <tt>T</tt> is a type to be supplied by a C++ program
instantiating a template, <tt>a</tt>, <tt>b</tt>, and <tt>c</tt> are
values of type <tt>const T</tt>.
</p>

<p>25 Between p8 and p9</p>

<p>Add the following sentence:</p>

<p>When the description of an algorithm gives an expression such as
<tt>*first == value</tt> for a condition, it is required that the expression
evaluate to either true or false in boolean contexts.</p>

<p>25.1.2 Change p1 by deleting the requires clause.</p>

<p>25.1.6 Change p1 by deleting the requires clause.</p>

<p>25.1.9</p>

<p>Change p4 from</p>

<p>-4- Requires: Type <tt>T</tt> is <tt>EqualityComparable</tt>
(20.1.1), type Size is convertible to integral type (4.7.12.3).
</p>

<p>to</p>

<p>-4- Requires: The type <tt>Size</tt> is convertible to integral
type (4.7.12.3).</p>

<p>25.2.4 Change p1 from</p>

<p>-1- Requires: Type <tt>T</tt> is <tt>Assignable</tt> (23.1 ) (and, for <tt>replace()</tt>, <tt>EqualityComparable</tt> (20.1.1 )).</p>

<p>to</p>

<p>-1- Requires: The expression <tt>*first = new_value</tt> must be valid.</p>

<p>and change p4 from</p>

<p>-4- Requires: Type <tt>T</tt> is <tt>Assignable</tt> (23.1) (and,
for <tt>replace_copy()</tt>, <tt>EqualityComparable</tt>
(20.1.1)). The ranges <tt>[first, last)</tt> and <tt>[result, result +
(last - first))</tt> shall not overlap.</p>

<p>to</p>

<p>-4- Requires: The results of the expressions <tt>*first</tt> and
<tt>new_value</tt> must be writable to the result output iterator. The
ranges <tt>[first, last)</tt> and <tt>[result, result + (last -
first))</tt> shall not overlap.</p>


<p>25.2.5 Change p1 from</p>

<p>-1- Requires: Type <tt>T</tt> is <tt>Assignable</tt> (23.1). The
type <tt>Size</tt> is convertible to an integral type (4.7.12.3).</p>

<p>to</p>

<p>-1- Requires: The expression <tt>value</tt> must be is writable to
the output iterator. The type <tt>Size</tt> is convertible to an
integral type (4.7.12.3).</p>

<p>25.2.7 Change p1 from</p>

<p>-1- Requires: Type <tt>T</tt> is <tt>EqualityComparable</tt> (20.1.1).</p>

<p>to</p>

<p>
-1- Requires: The value type of the iterator must be
<tt>Assignable</tt> (23.1).
</p>

<p><b>Rationale:</b></p>
<p>
The general idea of the proposed solution is to remove the faulty
requires clauses and let the returns and effects clauses speak for
themselves. That is, the returns clauses contain expressions that must
be valid, and therefore already imply the correct requirements. In
addition, a sentence is added at the beginning of chapter 25 saying
that expressions given as conditions must evaluate to true or false in
a boolean context. An alternative would be to say that the type of
these condition expressions must be literally bool, but that would be
imposing a greater restriction that what the standard currently says
(which is convertible to bool).
</p>
<hr>
<a name="284"><h3>284.&nbsp;unportable example in 20.3.7, p6</h3></a><p><b>Section:</b>&nbsp;20.5.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.comparisons"> [lib.comparisons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;26 Dec 2000</p>
<p>The example in 20.5.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.comparisons"> [lib.comparisons]</a>, p6 shows how to use the C
library function <tt>strcmp()</tt> with the function pointer adapter
<tt>ptr_fun()</tt>. But since it's unspecified whether the C library
functions have <tt>extern "C"</tt> or <tt>extern
"C++"</tt> linkage [17.4.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.using.linkage"> [lib.using.linkage]</a>], and since
function pointers with different the language linkage specifications
(7.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/dcl.html#dcl.link"> [dcl.link]</a>) are incompatible, whether this example is
well-formed is unspecified.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change 20.5.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.comparisons"> [lib.comparisons]</a> paragraph 6 from:</p>
<blockquote>
  <p>[<i>Example:</i></p>
  <pre>    replace_if(v.begin(), v.end(), not1(bind2nd(ptr_fun(strcmp), "C")), "C++");
  </pre>
  <p>replaces each <tt>C</tt> with <tt>C++</tt> in sequence <tt>v</tt>.</p>
</blockquote>


<p>to:</p>
<blockquote>
  <p>[<i>Example:</i></p>
  <pre>    int compare(const char*, const char*);
    replace_if(v.begin(), v.end(),
               not1(bind2nd(ptr_fun(compare), "abc")), "def");
  </pre>
  <p>replaces each <tt>abc</tt> with <tt>def</tt> in sequence <tt>v</tt>.</p>
</blockquote>

<p>Also, remove footnote 215 in that same paragraph.</p>

<p><i>[Copenhagen: Minor change in the proposed resolution.  Since this
issue deals in part with C and C++ linkage, it was believed to be too
confusing for the strings in the example to be "C" and "C++".
]</i></p>

<p><i>[Redmond: More minor changes.  Got rid of the footnote (which
seems to make a sweeping normative requirement, even though footnotes
aren't normative), and changed the sentence after the footnote so that
it corresponds to the new code fragment.]</i></p>

<hr>
<a name="285"><h3>285.&nbsp;minor editorial errors in fstream ctors</h3></a><p><b>Section:</b>&nbsp;27.8.1.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ifstream.cons"> [lib.ifstream.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;31 Dec 2000</p>
<p>27.8.1.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ifstream.cons"> [lib.ifstream.cons]</a>, p2, 27.8.1.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ofstream.cons"> [lib.ofstream.cons]</a>, p2, and
27.8.1.12 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstream.cons"> [lib.fstream.cons]</a>, p2 say about the effects of each constructor:
</p>

<p>... If that function returns a null pointer, calls
<tt>setstate(failbit)</tt> (which may throw <tt>ios_base::failure</tt>).
</p>

<p>The parenthetical note doesn't apply since the ctors cannot throw an
exception due to the requirement in 27.4.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.cons"> [lib.basic.ios.cons]</a>, p3 
that <tt>exceptions()</tt> be initialized to <tt>ios_base::goodbit</tt>.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Strike the parenthetical note from the Effects clause in each of the
paragraphs mentioned above.
</p>
<hr>
<a name="286"><h3>286.&nbsp;&lt;cstdlib&gt; requirements missing size_t typedef</h3></a><p><b>Section:</b>&nbsp;25.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.c.library"> [lib.alg.c.library]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;30 Dec 2000</p>
<p>
The &lt;cstdlib&gt; header file contains prototypes for bsearch and
qsort (C++ Standard section 25.4 paragraphs 3 and 4) and other
prototypes (C++ Standard section 21.4 paragraph 1 table 49) that
require the typedef size_t. Yet size_t is not listed in the
&lt;cstdlib&gt; synopsis table 78 in section 25.4.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add the type size_t to Table 78 (section 25.4) and add
the type size_t &lt;cstdlib&gt; to Table 97 (section C.2).
</p>
<p><b>Rationale:</b></p>
<p>Since size_t is in &lt;stdlib.h&gt;, it must also be in &lt;cstdlib&gt;.</p>
<hr>
<a name="288"><h3>288.&nbsp;&lt;cerrno&gt; requirements missing macro EILSEQ</h3></a><p><b>Section:</b>&nbsp;19.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-diagnostics.html#lib.errno"> [lib.errno]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Judy Ward&nbsp; <b>Date:</b>&nbsp;30 Dec 2000</p>
<p>
ISO/IEC 9899:1990/Amendment1:1994 Section 4.3 States: "The list
of macros defined in &lt;errno.h&gt; is adjusted to include a new
macro, EILSEQ"
</p>

<p>
ISO/IEC 14882:1998(E) section 19.3 does not refer
to the above amendment.
</p>

<p><b>Proposed resolution:</b></p>
<p>
Update Table 26 (section 19.3) "Header  &lt;cerrno&gt; synopsis"
and Table 95 (section C.2) "Standard Macros" to include EILSEQ.
</p>
<hr>
<a name="291"><h3>291.&nbsp;Underspecification of set algorithms</h3></a><p><b>Section:</b>&nbsp;25.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.set.operations"> [lib.alg.set.operations]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;03 Jan 2001</p>
<p>
The standard library contains four algorithms that compute set
operations on sorted ranges: <tt>set_union</tt>, <tt>set_intersection</tt>,
<tt>set_difference</tt>, and <tt>set_symmetric_difference</tt>.  Each
of these algorithms takes two sorted ranges as inputs, and writes the
output of the appropriate set operation to an output range.  The elements
in the output range are sorted.
</p>

<p>
The ordinary mathematical definitions are generalized so that they
apply to ranges containing multiple copies of a given element.  Two
elements are considered to be "the same" if, according to an
ordering relation provided by the user, neither one is less than the
other.  So, for example, if one input range contains five copies of an
element and another contains three, the output range of <tt>set_union</tt>
will contain five copies, the output range of
<tt>set_intersection</tt> will contain three, the output range of
<tt>set_difference</tt> will contain two, and the output range of
<tt>set_symmetric_difference</tt> will contain two.
</p>

<p>
Because two elements can be "the same" for the purposes
of these set algorithms, without being identical in other respects
(consider, for example, strings under case-insensitive comparison),
this raises a number of unanswered questions:
</p>

<ul>
<li>If we're copying an element that's present in both of the
input ranges, which one do we copy it from?</li>
<li>If there are <i>n</i> copies of an element in the relevant
input range, and the output range will contain fewer copies (say
<i>m</i>) which ones do we choose?  The first <i>m</i>, or the last
<i>m</i>, or something else?</li>
<li>Are these operations stable?  That is, does a run of equivalent
elements appear in the output range in the same order as as it
appeared in the input range(s)?</li>
</ul>

<p>
The standard should either answer these questions, or explicitly
say that the answers are unspecified.  I prefer the former option,
since, as far as I know, all existing implementations behave the
same way.
</p>

<p><b>Proposed resolution:</b></p>

<p>Add the following to the end of 25.3.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.set.union"> [lib.set.union]</a> paragraph 5:</p>
<blockquote>
If [first1, last1) contains <i>m</i> elements that are equivalent to
each other and [first2, last2) contains <i>n</i> elements that are
equivalent to them, then max(<i>m</i>, <i>n</i>) of these elements
will be copied to the output range: all <i>m</i> of these elements
from [first1, last1), and the last max(<i>n-m</i>, 0) of them from
[first2, last2), in that order.
</blockquote>

<p>Add the following to the end of 25.3.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.set.intersection"> [lib.set.intersection]</a> paragraph 5:</p>
<blockquote>
If [first1, last1) contains <i>m</i> elements that are equivalent to each
other and [first2, last2) contains <i>n</i> elements that are
equivalent to them, the first min(<i>m</i>, <i>n</i>) of those 
elements from [first1, last1) are copied to the output range.
</blockquote>

<p>Add a new paragraph, <b>Notes</b>, after 25.3.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.set.difference"> [lib.set.difference]</a>
paragraph 4:</p>
<blockquote>
If [first1, last1) contains <i>m</i> elements that are equivalent to each
other and [first2, last2) contains <i>n</i> elements that are
equivalent to them, the last max(<i>m-n</i>, 0) elements from 
[first1, last1) are copied to the output range.
</blockquote>

<p>Add a new paragraph, <b>Notes</b>, after 25.3.5.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.set.symmetric.difference"> [lib.set.symmetric.difference]</a>
paragraph 4:</p>
<blockquote>
If [first1, last1) contains <i>m</i> elements that are equivalent to
each other and [first2, last2) contains <i>n</i> elements that are
equivalent to them, then |<i>m - n</i>| of those elements will be
copied to the output range: the last <i>m - n</i> of these elements
from [first1, last1) if <i>m</i> &gt; <i>n</i>, and the last <i>n -
m</i> of these elements from [first2, last2) if <i>m</i> &lt; <i>n</i>.
</blockquote>

<p><i>[Santa Cruz: it's believed that this language is clearer than
  what's in the Standard.  However, it's also believed that the
  Standard may already make these guarantees (although not quite in
  these words).  Bill and Howard will check and see whether they think
  that some or all of these changes may be redundant.  If so, we may
  close this issue as NAD.]</i></p>

<p><b>Rationale:</b></p>
<p>For simple cases, these descriptions are equivalent to what's
  already in the Standard.  For more complicated cases, they describe
  the behavior of existing implementations.</p>
<hr>
<a name="292"><h3>292.&nbsp;effects of a.copyfmt (a)</h3></a><p><b>Section:</b>&nbsp;27.4.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.basic.ios.members"> [lib.basic.ios.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;05 Jan 2001</p>
<p>The Effects clause of the member function <tt>copyfmt()</tt> in
27.4.4.2, p15 doesn't consider the case where the left-hand side
argument is identical to the argument on the right-hand side, that is
<tt>(this == &amp;rhs)</tt>.  If the two arguments are identical there
is no need to copy any of the data members or call any callbacks
registered with <tt>register_callback()</tt>.  Also, as Howard Hinnant
points out in message c++std-lib-8149 it appears to be incorrect to
allow the object to fire <tt>erase_event</tt> followed by
<tt>copyfmt_event</tt> since the callback handling the latter event
may inadvertently attempt to access memory freed by the former.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the Effects clause in 27.4.4.2, p15 from</p>

<blockquote>
<b>-15- Effects:</b>Assigns to the member objects of <tt>*this</tt>
the corresponding member objects of <tt>rhs</tt>, except that...
</blockquote>

<p>to</p>

<blockquote>
<b>-15- Effects:</b>If <tt>(this == &amp;rhs)</tt> does nothing. Otherwise
assigns to the member objects of <tt>*this</tt> the corresponding member
objects of <tt>rhs</tt>, except that...
</blockquote>
<hr>
<a name="294"><h3>294.&nbsp;User defined macros and standard headers</h3></a><p><b>Section:</b>&nbsp;17.4.3.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.macro.names"> [lib.macro.names]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;James Kanze&nbsp; <b>Date:</b>&nbsp;11 Jan 2001</p>
<p>Paragraph 2 of 17.4.3.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.macro.names"> [lib.macro.names]</a> reads: "A
translation unit that includes a header shall not contain any macros
that define names declared in that header." As I read this, it
would mean that the following program is legal:</p>

<pre>  #define npos 3.14
  #include &lt;sstream&gt;
</pre>

<p>since npos is not defined in &lt;sstream&gt;.  It is, however, defined
in &lt;string&gt;, and it is hard to imagine an implementation in
which &lt;sstream&gt; didn't include &lt;string&gt;.</p>

<p>I think that this phrase was probably formulated before it was
decided that a standard header may freely include other standard
headers.  The phrase would be perfectly appropriate for C, for
example.  In light of 17.4.4.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.headers"> [lib.res.on.headers]</a> paragraph 1, however,
it isn't stringent enough.</p>
<p><b>Proposed resolution:</b></p>
<p>For 17.4.3.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.macro.names"> [lib.macro.names]</a>, replace the current wording, which reads:</p>
<blockquote>
     <p>Each name defined as a macro in a header is reserved to the
     implementation for any use if the translation unit includes
     the header.168)</p>

     <p>A translation unit that includes a header shall not contain any
     macros that define names declared or defined in that header. Nor shall
     such a translation unit define macros for names lexically
     identical to keywords.</p>

     <p>168) It is not permissible to remove a library macro definition by
     using the #undef directive.</p>
</blockquote>

<p>with the wording:</p>

<blockquote>
     <p>A translation unit that includes a standard library header shall not
     #define or #undef names declared in any standard library header.</p>

     <p>A translation unit shall not #define or #undef names lexically
     identical to keywords.</p>
</blockquote>

<p><i>[Lillehammer: Beman provided new wording]</i></p>

<hr>
<a name="295"><h3>295.&nbsp;Is abs defined in &lt;cmath&gt;?</h3></a><p><b>Section:</b>&nbsp;26.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.numarray"> [lib.numarray]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Jens Maurer&nbsp; <b>Date:</b>&nbsp;12 Jan 2001</p>
<p>
Table 80 lists the contents of the &lt;cmath&gt; header.  It does not
list <tt>abs()</tt>.  However, 26.5, paragraph 6, which lists added 
signatures present in &lt;cmath&gt;, does say that several overloads
of <tt>abs()</tt> should be defined in &lt;cmath&gt;.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add <tt>abs</tt> to Table 80.  Also, remove the parenthetical list
of functions "(abs(), div(), rand(), srand())" from 26.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.numarray"> [lib.numarray]</a>,
paragraph 1.
</p>

<p><i>[Copenhagen: Modified proposed resolution so that it also gets
rid of that vestigial list of functions in paragraph 1.]</i></p>

<p><b>Rationale:</b></p>
<p>All this DR does is fix a typo; it's uncontroversial.  A 
separate question is whether we're doing the right thing in 
putting some overloads in &lt;cmath&gt; that we aren't also 
putting in &lt;cstdlib&gt;.  That's issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#323">323</a>.</p>
<hr>
<a name="297"><h3>297.&nbsp;const_mem_fun_t&lt;&gt;::argument_type should be const T*</h3></a><p><b>Section:</b>&nbsp;20.5.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.logical.operations"> [lib.logical.operations]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;6 Jan 2001</p>
<p>The class templates <tt>const_mem_fun_t</tt> in 20.5.8, p8 and
<tt>const_mem_fun1_t</tt>
in 20.5.8, p9 derive from <tt>unary_function&lt;T*, S&gt;</tt>, and
<tt>binary_function&lt;T*,
A, S&gt;</tt>, respectively. Consequently, their <tt>argument_type</tt>, and
<tt>first_argument_type</tt>
members, respectively, are both defined to be <tt>T*</tt> (non-const).
However, their function call member operator takes a <tt>const T*</tt>
argument. It is my opinion that <tt>argument_type</tt> should be <tt>const
T*</tt> instead, so that one can easily refer to it in generic code. The
example below derived from existing code fails to compile due to the
discrepancy:
</p>

<p><tt>template &lt;class T&gt;</tt>
<br><tt>void foo (typename T::argument_type arg)&nbsp;&nbsp; // #1</tt>
<br><tt>{</tt>
<br><tt>&nbsp;&nbsp;&nbsp; typename T::result_type (T::*pf) (typename
T::argument_type)
const =&nbsp;&nbsp; // #2</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &amp;T::operator();</tt>
<br><tt>}</tt>
</p>

<p><tt>struct X { /* ... */ };</tt></p>

<p><tt>int main ()</tt>
<br><tt>{</tt>
<br><tt>&nbsp;&nbsp;&nbsp; const X x;</tt>
<br><tt>&nbsp;&nbsp;&nbsp; foo&lt;std::const_mem_fun_t&lt;void, X&gt;
&gt;(&amp;x);&nbsp;&nbsp;
// #3</tt>
<br><tt>}</tt>
</p>

<p>#1 <tt>foo()</tt> takes a plain unqualified <tt>X*</tt> as an argument
<br>#2 the type of the pointer is incompatible with the type of the member
function
<br>#3 the address of a constant being passed to a function taking a non-const
<tt>X*</tt>
</p>
<p><b>Proposed resolution:</b></p>
<p>Replace the top portion of the definition of the class template
const_mem_fun_t in 20.5.8, p8
</p>
<p><tt>template &lt;class S, class T&gt; class const_mem_fun_t</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; : public
unary_function&lt;T*, S&gt; {</tt>
</p>
<p>with</p>
<p><tt>template &lt;class S, class T&gt; class const_mem_fun_t</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; : public
unary_function&lt;<b>const</b> T*, S&gt; {</tt>
</p>
<p>Also replace the top portion of the definition of the class template
const_mem_fun1_t in 20.5.8, p9</p>
<p><tt>template &lt;class S, class T, class A&gt; class const_mem_fun1_t</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; : public
binary_function&lt;T*, A, S&gt; {</tt>
</p>
<p>with</p>
<p><tt>template &lt;class S, class T, class A&gt; class const_mem_fun1_t</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; : public
binary_function&lt;<b>const</b> T*, A, S&gt; {</tt>
</p>
<p><b>Rationale:</b></p>
<p>This is simply a contradiction: the <tt>argument_type</tt> typedef,
and the argument type itself, are not the same.</p>
<hr>
<a name="298"><h3>298.&nbsp;::operator delete[] requirement incorrect/insufficient</h3></a><p><b>Section:</b>&nbsp;18.5.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.array"> [lib.new.delete.array]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;John A. Pedretti&nbsp; <b>Date:</b>&nbsp;10 Jan 2001</p>
<p>
The default behavior of <tt>operator delete[]</tt> described in 18.5.1.2, p12 -
namely that for non-null value of <i>ptr</i>, the operator reclaims storage
allocated by the earlier call to the default <tt>operator new[]</tt> - is not
correct in all cases. Since the specified <tt>operator new[]</tt> default
behavior is to call <tt>operator new</tt> (18.5.1.2, p4, p8), which can be
replaced, along with <tt>operator delete</tt>, by the user, to implement their
own memory management, the specified default behavior of<tt> operator
delete[]</tt> must be to call <tt>operator delete</tt>.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change 18.5.1.2, p12 from</p>
<blockquote>
<b>-12-</b> <b>Default behavior:</b>
<ul>
<li>
For a null value of <i><tt>ptr</tt></i> , does nothing.
</li>
<li>
Any other value of <i><tt>ptr</tt></i> shall be a value returned
earlier by a call to the default <tt>operator new[](std::size_t)</tt>.
[Footnote: The value must not have been invalidated by an intervening
call to <tt>operator delete[](void*)</tt> (17.4.3.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.arguments"> [lib.res.on.arguments]</a>).
--- end footnote]
For such a non-null value of <i><tt>ptr</tt></i> , reclaims storage
allocated by the earlier call to the default <tt>operator new[]</tt>.
</li>
</ul>
</blockquote>

<p>to</p>

<blockquote>
<b>-12-</b> <b>Default behavior: </b>Calls <tt>operator
delete(</tt><i>ptr</i>)
or <tt>operator delete(<i>ptr</i>, std::nothrow)</tt> respectively.
</blockquote>
<p>and expunge paragraph 13.</p>
<hr>
<a name="300"><h3>300.&nbsp;list::merge() specification incomplete</h3></a><p><b>Section:</b>&nbsp;23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;John Pedretti&nbsp; <b>Date:</b>&nbsp;23 Jan 2001</p>
<p>
The "Effects" clause for list::merge() (23.2.2.4, p23)
appears to be incomplete: it doesn't cover the case where the argument
list is identical to *this (i.e., this == &amp;x). The requirement in the
note in p24 (below) is that x be empty after the merge which is surely
unintended in this case.
</p>
<p><b>Proposed resolution:</b></p>
<p>In 23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>, replace paragraps 23-25 with:</p>
<blockquote>
<p>
23 Effects: if (&amp;x == this) does nothing; otherwise, merges the two
sorted ranges [begin(), end()) and [x.begin(), x.end()).  The result
is a range in which the elements will be sorted in non-decreasing
order according to the ordering defined by comp; that is, for every
iterator i in the range other than the first, the condition comp(*i,
*(i - 1)) will be false.
</p>

<p>
24 Notes: Stable: if (&amp;x != this), then for equivalent elements in the
two original ranges, the elements from the original range [begin(),
end()) always precede the elements from the original range [x.begin(),
x.end()).  If (&amp;x != this) the range [x.begin(), x.end()) is empty
after the merge.
</p>

<p>
25 Complexity: At most size() + x.size() - 1 applications of comp if
(&amp;x !  = this); otherwise, no applications of comp are performed.  If
an exception is thrown other than by a comparison there are no
effects.
</p>

</blockquote>

<p><i>[Copenhagen: The original proposed resolution did not fix all of
the problems in 23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>, p22-25.  Three different
paragraphs (23, 24, 25) describe the effects of <tt>merge</tt>.
Changing p23, without changing the other two, appears to introduce
contradictions.  Additionally, "merges the argument list into the
list" is excessively vague.]</i></p>

<p><i>[Post-Curaçao: Robert Klarer provided new wording.]</i></p>

<hr>
<a name="301"><h3>301.&nbsp;basic_string template ctor effects clause omits allocator argument</h3></a><p><b>Section:</b>&nbsp;21.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.cons"> [lib.string.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;27 Jan 2001</p>
<p>
The effects clause for the basic_string template ctor in 21.3.1, p15
leaves out the third argument of type Allocator. I believe this to be
a mistake.
</p>
<p><b>Proposed resolution:</b></p>
<p>Replace</p>

<blockquote>
    <p><b>-15- Effects:</b> If <i><tt>InputIterator</tt></i> is an integral
    type, equivalent to</p>

    <blockquote><tt>basic_string(static_cast&lt;size_type&gt;(begin),
    static_cast&lt;value_type&gt;(end))</tt></blockquote>
</blockquote>

<p>with</p>

<blockquote>
    <p><b>-15- Effects:</b> If <i><tt>InputIterator</tt></i> is an integral
    type, equivalent to</p>

    <blockquote><tt>basic_string(static_cast&lt;size_type&gt;(begin),
    static_cast&lt;value_type&gt;(end), <b>a</b>)</tt></blockquote>
</blockquote>
<hr>
<a name="303"><h3>303.&nbsp;Bitset input operator underspecified</h3></a><p><b>Section:</b>&nbsp;23.3.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.operators"> [lib.bitset.operators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;5 Feb 2001</p>
<p>
In 23.3.5.3, we are told that <tt>bitset</tt>'s input operator
"Extracts up to <i>N</i> (single-byte) characters from
<i>is</i>.", where <i>is</i> is a stream of type
<tt>basic_istream&lt;charT, traits&gt;</tt>.
</p>

<p>
The standard does not say what it means to extract single byte
characters from a stream whose character type, <tt>charT</tt>, is in
general not a single-byte character type.  Existing implementations
differ.
</p>

<p>
A reasonable solution will probably involve <tt>widen()</tt> and/or
<tt>narrow()</tt>, since they are the supplied mechanism for
converting a single character between <tt>char</tt> and 
arbitrary <tt>charT</tt>.
</p>

<p>Narrowing the input characters is not the same as widening the
literals <tt>'0'</tt> and <tt>'1'</tt>, because there may be some
locales in which more than one wide character maps to the narrow
character <tt>'0'</tt>.  Narrowing means that alternate
representations may be used for bitset input, widening means that
they may not be.</p>

<p>Note that for numeric input, <tt>num_get&lt;&gt;</tt>
(22.2.2.1.2/8) compares input characters to widened version of narrow
character literals.</p>

<p>From Pete Becker, in c++std-lib-8224:</p>
<blockquote>
<p>
Different writing systems can have different representations for the
digits that represent 0 and 1. For example, in the Unicode representation
of the Devanagari script (used in many of the Indic languages) the digit 0
is 0x0966, and the digit 1 is 0x0967. Calling narrow would translate those
into '0' and '1'. But Unicode also provides the ASCII values 0x0030 and
0x0031 for for the Latin representations of '0' and '1', as well as code
points for the same numeric values in several other scripts (Tamil has no
character for 0, but does have the digits 1-9), and any of these values
would also be narrowed to '0' and '1'.
</p>

<p>...</p>

<p>
It's fairly common to intermix both native and Latin
representations of numbers in a document. So I think the rule has to be
that if a wide character represents a digit whose value is 0 then the bit
should be cleared; if it represents a digit whose value is 1 then the bit
should be set; otherwise throw an exception. So in a Devanagari locale,
both 0x0966 and 0x0030 would clear the bit, and both 0x0967 and 0x0031
would set it. Widen can't do that. It would pick one of those two values,
and exclude the other one.
</p>

</blockquote>

<p>From Jens Maurer, in c++std-lib-8233:</p>

<blockquote>
<p>
Whatever we decide, I would find it most surprising if
bitset conversion worked differently from int conversion
with regard to alternate local representations of
numbers.
</p>

<p>Thus, I think the options are:</p>
<ul>
 <li> Have a new defect issue for 22.2.2.1.2/8 so that it will
require the use of narrow().</li>

 <li> Have a defect issue for bitset() which describes clearly
that widen() is to be used.</li>
</ul>
</blockquote>
<p><b>Proposed resolution:</b></p>

    <p>Replace the first two sentences of paragraph 5 with:</p>

    <blockquote>
    Extracts up to <i>N</i> characters from <i>is</i>. Stores these
    characters in a temporary object <i>str</i> of type
    <tt>basic_string&lt;charT, traits&gt;</tt>, then evaluates the
    expression <tt><i>x</i> = bitset&lt;N&gt;(<i>str</i>)</tt>.
    </blockquote>

    <p>Replace the third bullet item in paragraph 5 with:</p>
    <ul><li>
    the next input character is neither <tt><i>is</i>.widen(0)</tt>
    nor <tt><i>is</i>.widen(1)</tt> (in which case the input character
    is not extracted).
    </li></ul>

<p><b>Rationale:</b></p>
<p>Input for <tt>bitset</tt> should work the same way as numeric
input.  Using <tt>widen</tt> does mean that alternative digit
representations will not be recognized, but this was a known 
consequence of the design choice.</p>
<hr>
<a name="305"><h3>305.&nbsp;Default behavior of codecvt&lt;wchar_t, char, mbstate_t&gt;::length()</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;24 Jan 2001</p>
<p>22.2.1.5/3 introduces codecvt in part with:</p>

<blockquote>
  codecvt&lt;wchar_t,char,mbstate_t&gt; converts between the native
  character sets for tiny and wide characters. Instantiations on
  mbstate_t perform conversion between encodings known to the library
  implementor.
</blockquote>

<p>But 22.2.1.5.2/10 describes do_length in part with:</p>

<blockquote>
  ... codecvt&lt;wchar_t, char, mbstate_t&gt; ... return(s) the lesser of max and 
  (from_end-from).
</blockquote>

<p>
The semantics of do_in and do_length are linked.  What one does must
be consistent with what the other does.  22.2.1.5/3 leads me to
believe that the vendor is allowed to choose the algorithm that
codecvt&lt;wchar_t,char,mbstate_t&gt;::do_in performs so that it makes
his customers happy on a given platform.  But 22.2.1.5.2/10 explicitly
says what codecvt&lt;wchar_t,char,mbstate_t&gt;::do_length must
return.  And thus indirectly specifies the algorithm that
codecvt&lt;wchar_t,char,mbstate_t&gt;::do_in must perform.  I believe
that this is not what was intended and is a defect.
</p>

<p>Discussion from the -lib reflector:

<br>This proposal would have the effect of making the semantics of
all of the virtual functions in <tt>codecvt&lt;wchar_t, char,
mbstate_t&gt;</tt> implementation specified.  Is that what we want, or
do we want to mandate specific behavior for the base class virtuals
and leave the implementation specified behavior for the codecvt_byname
derived class?  The tradeoff is that former allows implementors to
write a base class that actually does something useful, while the
latter gives users a way to get known and specified---albeit
useless---behavior, and is consistent with the way the standard
handles other facets.  It is not clear what the original intention
was.</p>

<p>
Nathan has suggest a compromise: a character that is a widened version
of the characters in the basic execution character set must be
converted to a one-byte sequence, but there is no such requirement
for characters that are not part of the basic execution character set.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 22.2.1.5.2/5 from:
</p>
<p>
The instantiations required in Table 51 (lib.locale.category), namely
codecvt&lt;wchar_t,char,mbstate_t&gt; and
codecvt&lt;char,char,mbstate_t&gt;, store no characters. Stores no more
than (to_limit-to) destination elements. It always leaves the to_next
pointer pointing one beyond the last element successfully stored.
</p>
<p>
to:
</p>
<p>
Stores no more than (to_limit-to) destination elements, and leaves the
to_next pointer pointing one beyond the last element successfully
stored.  codecvt&lt;char,char,mbstate_t&gt; stores no characters.
</p>

<p>Change 22.2.1.5.2/10 from:</p>

<blockquote>
-10- Returns: (from_next-from) where from_next is the largest value in
the range [from,from_end] such that the sequence of values in the
range [from,from_next) represents max or fewer valid complete
characters of type internT. The instantiations required in Table 51
(21.1.1.1.1), namely codecvt&lt;wchar_t, char, mbstate_t&gt; and
codecvt&lt;char, char, mbstate_t&gt;, return the lesser of max and
(from_end-from).
</blockquote>

<p>to:</p>

<blockquote>
-10- Returns: (from_next-from) where from_next is the largest value in 
the range [from,from_end] such that the sequence of values in the range 
[from,from_next) represents max or fewer valid complete characters of 
type internT. The instantiation codecvt&lt;char, char, mbstate_t&gt; returns 
the lesser of max and (from_end-from). 
</blockquote>

<p><i>[Redmond: Nathan suggested an alternative resolution: same as
above, but require that, in the default encoding, a character from the
basic execution character set would map to a single external
character.  The straw poll was 8-1 in favor of the proposed
resolution.]</i></p>

<p><b>Rationale:</b></p>
<p>The default encoding should be whatever users of a given platform
would expect to be the most natural.  This varies from platform to
platform.  In many cases there is a preexisting C library, and users
would expect the default encoding to be whatever C uses in the default
"C" locale.  We could impose a guarantee like the one Nathan suggested
(a character from the basic execution character set must map to a
single external character), but this would rule out important
encodings that are in common use: it would rule out JIS, for
example, and it would rule out a fixed-width encoding of UCS-4.</p>

<p><i>[Curaçao: fixed rationale typo at the request of Ichiro Koshida;
"shift-JIS" changed to "JIS".]</i></p>

<hr>
<a name="306"><h3>306.&nbsp;offsetof macro and non-POD types</h3></a><p><b>Section:</b>&nbsp;18.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.support.types"> [lib.support.types]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;21 Feb 2001</p> 
<p>Spliced together from reflector messages c++std-lib-8294 and -8295:</p>

<p>18.1, paragraph 5, reads: "The macro <tt>offsetof</tt>
accepts a restricted set of <i>type</i> arguments in this
International Standard. <i>type</i> shall be a POD structure or a POD
union (clause 9). The result of applying the offsetof macro to a field
that is a static data member or a function member is
undefined."</p>

<p>For the POD requirement, it doesn't say "no diagnostic
required" or "undefined behavior". I read 1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/intro.html#intro.compliance"> [intro.compliance]</a>, paragraph 1, to mean that a diagnostic is required.
It's not clear whether this requirement was intended.  While it's
possible to provide such a diagnostic, the extra complication doesn't
seem to add any value.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change 18.1, paragraph 5, to "If <i>type</i> is not a POD
structure or a POD union the results are undefined."</p>

<p><i>[Copenhagen: straw poll was 7-4 in favor.  It was generally
agreed that requiring a diagnostic was inadvertent, but some LWG
members thought that diagnostics should be required whenever
possible.]</i></p>

<hr>
<a name="307"><h3>307.&nbsp;Lack of reference typedefs in container adaptors</h3></a><p><b>Section:</b>&nbsp;23.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list"> [lib.list]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;13 Mar 2001</p>

<p>From reflector message c++std-lib-8330.  See also lib-8317.</p>

<p>
The standard is currently inconsistent in 23.2.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.capacity"> [lib.list.capacity]</a>
paragraph 1 and 23.2.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.modifiers"> [lib.list.modifiers]</a> paragraph 1.
23.2.3.3/1, for example, says:
</p>

<blockquote>
-1- Any sequence supporting operations back(), push_back() and pop_back() 
can be used to instantiate stack. In particular, vector (lib.vector), list 
(lib.list) and deque (lib.deque) can be used. 
</blockquote>

<p>But this is false: vector&lt;bool&gt; can not be used, because the
container adaptors return a T&amp; rather than using the underlying
container's reference type.</p>

<p>This is a contradiction that can be fixed by:</p>

<ol>
<li>Modifying these paragraphs to say that vector&lt;bool&gt;
    is an exception.</li>
<li>Removing the vector&lt;bool&gt; specialization.</li>
<li>Changing the return types of stack and priority_queue to use 
    reference typedef's.</li>
</ol>

<p>
I propose 3.  This does not preclude option 2 if we choose to do it
later (see issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#96">96</a>); the issues are independent.  Option
3 offers a small step towards support for proxied containers.  This
small step fixes a current contradiction, is easy for vendors to
implement, is already implemented in at least one popular lib, and
does not break any code.
</p>

<p><b>Proposed resolution:</b></p>
<p>Summary: Add reference and const_reference typedefs to queue,
priority_queue and stack.  Change return types of "value_type&amp;" to
"reference".  Change return types of "const value_type&amp;" to
"const_reference".  Details:</p>

<p>Change 23.2.3.1/1 from:</p>

<pre>  namespace std {
    template &lt;class T, class Container = deque&lt;T&gt; &gt;
    class queue {
    public:
      typedef typename Container::value_type            value_type;
      typedef typename Container::size_type             size_type;
      typedef          Container                        container_type;
    protected:
      Container c;

    public:
      explicit queue(const Container&amp; = Container());

      bool      empty() const             { return c.empty(); }
      size_type size()  const             { return c.size(); }
      value_type&amp;       front()           { return c.front(); }
      const value_type&amp; front() const     { return c.front(); }
      value_type&amp;       back()            { return c.back(); }
      const value_type&amp; back() const      { return c.back(); }
      void push(const value_type&amp; x)      { c.push_back(x); }
      void pop()                          { c.pop_front(); }
    };
</pre>

<p>to:</p>

<pre>  namespace std {
    template &lt;class T, class Container = deque&lt;T&gt; &gt;
    class queue {
    public:
      typedef typename Container::value_type            value_type;
      typedef typename Container::reference             reference;
      typedef typename Container::const_reference       const_reference;
      typedef typename Container::value_type            value_type;
      typedef typename Container::size_type             size_type;
      typedef          Container                        container_type;
    protected:
      Container c;

    public:
      explicit queue(const Container&amp; = Container());

      bool      empty() const             { return c.empty(); }
      size_type size()  const             { return c.size(); }
      reference         front()           { return c.front(); }
      const_reference   front() const     { return c.front(); }
      reference         back()            { return c.back(); }
      const_reference   back() const      { return c.back(); }
      void push(const value_type&amp; x)      { c.push_back(x); }
      void pop()                          { c.pop_front(); }
    };
</pre>

<p>Change 23.2.3.2/1 from:</p>

<pre>  namespace std {
    template &lt;class T, class Container = vector&lt;T&gt;,
              class Compare = less&lt;typename Container::value_type&gt; &gt;
    class priority_queue {
    public:
      typedef typename Container::value_type            value_type;
      typedef typename Container::size_type             size_type;
      typedef          Container                        container_type;
    protected:
      Container c;
      Compare comp;

    public:
      explicit priority_queue(const Compare&amp; x = Compare(),
                              const Container&amp; = Container());
      template &lt;class InputIterator&gt;
        priority_queue(InputIterator first, InputIterator last,
                       const Compare&amp; x = Compare(),
                       const Container&amp; = Container());

      bool      empty() const       { return c.empty(); }
      size_type size()  const       { return c.size(); }
      const value_type&amp; top() const { return c.front(); }
      void push(const value_type&amp; x);
      void pop();
    };
                                  //  no equality is provided
  }
</pre>

<p>to:</p>

<pre>  namespace std {
    template &lt;class T, class Container = vector&lt;T&gt;,
              class Compare = less&lt;typename Container::value_type&gt; &gt;
    class priority_queue {
    public:
      typedef typename Container::value_type            value_type;
      typedef typename Container::reference             reference;
      typedef typename Container::const_reference       const_reference;
      typedef typename Container::size_type             size_type;
      typedef          Container                        container_type;
    protected:
      Container c;
      Compare comp;

    public:
      explicit priority_queue(const Compare&amp; x = Compare(),
                              const Container&amp; = Container());
      template &lt;class InputIterator&gt;
        priority_queue(InputIterator first, InputIterator last,
                       const Compare&amp; x = Compare(),
                       const Container&amp; = Container());

      bool      empty() const       { return c.empty(); }
      size_type size()  const       { return c.size(); }
      const_reference   top() const { return c.front(); }
      void push(const value_type&amp; x);
      void pop();
    };
                                  //  no equality is provided
  }
</pre>

<p>And change 23.2.3.3/1 from:</p>

<pre>  namespace std {
    template &lt;class T, class Container = deque&lt;T&gt; &gt;
    class stack {
    public:
      typedef typename Container::value_type            value_type;
      typedef typename Container::size_type             size_type;
      typedef          Container                        container_type;
    protected:
      Container c;

    public:
      explicit stack(const Container&amp; = Container());

      bool      empty() const             { return c.empty(); }
      size_type size()  const             { return c.size(); }
      value_type&amp;       top()             { return c.back(); }
      const value_type&amp; top() const       { return c.back(); }
      void push(const value_type&amp; x)      { c.push_back(x); }
      void pop()                          { c.pop_back(); }
    };

    template &lt;class T, class Container&gt;
      bool operator==(const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator&lt; (const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator!=(const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator&gt; (const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator&gt;=(const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator&lt;=(const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
  }
</pre>

<p>to:</p>

<pre>  namespace std {
    template &lt;class T, class Container = deque&lt;T&gt; &gt;
    class stack {
    public:
      typedef typename Container::value_type            value_type;
      typedef typename Container::reference             reference;
      typedef typename Container::const_reference       const_reference;
      typedef typename Container::size_type             size_type;
      typedef          Container                        container_type;
    protected:
      Container c;

    public:
      explicit stack(const Container&amp; = Container());

      bool      empty() const             { return c.empty(); }
      size_type size()  const             { return c.size(); }
      reference         top()             { return c.back(); }
      const_reference   top() const       { return c.back(); }
      void push(const value_type&amp; x)      { c.push_back(x); }
      void pop()                          { c.pop_back(); }
    };

    template &lt;class T, class Container&gt;
      bool operator==(const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator&lt; (const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator!=(const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator&gt; (const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator&gt;=(const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
    template &lt;class T, class Container&gt;
      bool operator&lt;=(const stack&lt;T, Container&gt;&amp; x,
                      const stack&lt;T, Container&gt;&amp; y);
  }
</pre>

<p><i>[Copenhagen: This change was discussed before the IS was released
and it was deliberately not adopted.  Nevertheless, the LWG believes
(straw poll: 10-2) that it is a genuine defect.]</i></p>

<hr>
<a name="308"><h3>308.&nbsp;Table 82 mentions unrelated headers</h3></a><p><b>Section:</b>&nbsp;27 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.input.output"> [lib.input.output]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;15 Mar 2001</p>
<p>
Table 82 in section 27 mentions the header &lt;cstdlib&gt; for String
streams (27.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.string.streams"> [lib.string.streams]</a>) and the headers &lt;cstdio&gt; and
&lt;cwchar&gt; for File streams (27.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.file.streams"> [lib.file.streams]</a>). It's not clear
why these headers are mentioned in this context since they do not
define any of the library entities described by the
subclauses. According to 17.4.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.contents"> [lib.contents]</a>, only such headers
are to be listed in the summary.
</p>
<p><b>Proposed resolution:</b></p>
<p>Remove &lt;cstdlib&gt; and &lt;cwchar&gt; from
Table 82.</p>

<p><i>[Copenhagen: changed the proposed resolution slightly.  The
original proposed resolution also said to remove &lt;cstdio&gt; from
Table 82.  However, &lt;cstdio&gt; is mentioned several times within
section 27.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.file.streams"> [lib.file.streams]</a>, including 27.8.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.c.files"> [lib.c.files]</a>.]</i></p>

<hr>
<a name="310"><h3>310.&nbsp;Is errno a macro?</h3></a><p><b>Section:</b>&nbsp;17.4.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.headers"> [lib.headers]</a>, 19.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-diagnostics.html#lib.errno"> [lib.errno]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;21 Mar 2001</p>
  <p>
  Exactly how should errno be declared in a conforming C++ header?
  </p>

  <p>
  The C standard says in 7.1.4 that it is unspecified whether errno is a
  macro or an identifier with external linkage.  In some implementations
  it can be either, depending on compile-time options.  (E.g., on
  Solaris in multi-threading mode, errno is a macro that expands to a
  function call, but is an extern int otherwise.  "Unspecified" allows
  such variability.)
  </p>

  <p>The C++ standard:</p>
  <ul>
  <li>17.4.1.2 says in a note that errno must be macro in C. (false)</li>
  <li>17.4.3.1.3 footnote 166 says errno is reserved as an external 
      name (true), and implies that it is an identifier.</li>
  <li>19.3 simply lists errno as a macro (by what reasoning?) and goes
      on to say that the contents of of C++ &lt;errno.h&gt; are the
      same as in C, begging the question.</li>
  <li>C.2, table 95 lists errno as a macro, without comment.</li>
  </ul>

  <p>I find no other references to errno.</p>

  <p>We should either explicitly say that errno must be a macro, even
  though it need not be a macro in C, or else explicitly leave it
  unspecified.  We also need to say something about namespace std. 
  A user who includes &lt;cerrno&gt; needs to know whether to write
  <tt>errno</tt>, or <tt>::errno</tt>, or <tt>std::errno</tt>, or
  else &lt;cerrno&gt; is useless.</p>

  <p>Two acceptable fixes:</p>
  <ul>
    <li><p>errno must be a macro. This is trivially satisfied by adding<br>
        &nbsp;&nbsp;#define errno (::std::errno)<br>
        to the headers if errno is not already a macro. You then always
        write errno without any scope qualification, and it always expands
        to a correct reference. Since it is always a macro, you know to
        avoid using errno as a local identifer.</p></li>
    <li><p>errno is in the global namespace. This fix is inferior, because
        ::errno is not guaranteed to be well-formed.</p></li>
  </ul>

  <p><i>[
    This issue was first raised in 1999, but it slipped through 
    the cracks.
  ]</i></p>
<p><b>Proposed resolution:</b></p>
  <p>Change the Note in section 17.4.1.2p5 from</p>

    <blockquote>
    Note: the names defined as macros in C include the following:
    assert, errno, offsetof, setjmp, va_arg, va_end, and va_start.
    </blockquote>

  <p>to</p>

    <blockquote>
    Note: the names defined as macros in C include the following:
    assert, offsetof, setjmp, va_arg, va_end, and va_start.
    </blockquote>

  <p>In section 19.3, change paragraph 2 from</p>

    <blockquote>
    The contents are the same as the Standard C library header
    &lt;errno.h&gt;.
    </blockquote>

  <p>to</p>

    <blockquote>
    The contents are the same as the Standard C library header 
    &lt;errno.h&gt;, except that errno shall be defined as a macro.
    </blockquote>
<p><b>Rationale:</b></p>
<p>C++ must not leave it up to the implementation to decide whether or
not a name is a macro; it must explicitly specify exactly which names
are required to be macros.  The only one that really works is for it
to be a macro.</p>

<p><i>[Curaçao: additional rationale added.]</i></p>

<hr>
<a name="311"><h3>311.&nbsp;Incorrect wording in basic_ostream class synopsis</h3></a><p><b>Section:</b>&nbsp;27.6.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream"> [lib.ostream]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andy Sawyer&nbsp; <b>Date:</b>&nbsp;21 Mar 2001</p>

<p>In 27.6.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream"> [lib.ostream]</a>, the synopsis of class basic_ostream says:</p>

<pre>  // partial specializationss
  template&lt;class traits&gt;
    basic_ostream&lt;char,traits&gt;&amp; operator&lt;&lt;( basic_ostream&lt;char,traits&gt;&amp;,
                                            const char * );
</pre>

<p>Problems:</p>
<ul>
<li>Too many 's's at the end of "specializationss" </li>
<li>This is an overload, not a partial specialization</li>
</ul>

<p><b>Proposed resolution:</b></p>
<p>In the synopsis in 27.6.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream"> [lib.ostream]</a>, remove the 
<i>// partial specializationss</i> comment.  Also remove the same 
comment (correctly spelled, but still incorrect) from the synopsis in 
27.6.2.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters.character"> [lib.ostream.inserters.character]</a>.
</p>

<p><i>[
Pre-Redmond: added 27.6.2.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters.character"> [lib.ostream.inserters.character]</a> because of Martin's
comment in c++std-lib-8939.
]</i></p>

<hr>
<a name="312"><h3>312.&nbsp;Table 27 is missing headers</h3></a><p><b>Section:</b>&nbsp;20 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.utilities"> [lib.utilities]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;29 Mar 2001</p>
<p>Table 27 in section 20 lists the header &lt;memory&gt; (only) for
Memory (lib.memory) but neglects to mention the headers
&lt;cstdlib&gt; and &lt;cstring&gt; that are discussed in 20.4.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.rel"> [lib.meta.rel]</a>.</p>
<p><b>Proposed resolution:</b></p>
<p>Add &lt;cstdlib&gt; and &lt;cstring&gt; to Table 27, in the same row
as &lt;memory&gt;.</p>
<hr>
<a name="315"><h3>315.&nbsp;Bad "range" in list::unique complexity</h3></a><p><b>Section:</b>&nbsp;23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andy Sawyer&nbsp; <b>Date:</b>&nbsp;1 May 2001</p>
<p>
23.2.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.special"> [lib.deque.special]</a>, Para 21 describes the complexity of
list::unique as: "If the range (last - first) is not empty, exactly
(last - first) -1 applications of the corresponding predicate,
otherwise no applications of the predicate)".
</p>

<p>
"(last - first)" is not a range.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the "range" from (last - first) to [first, last).
</p>
<hr>
<a name="316"><h3>316.&nbsp;Vague text in Table 69</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;4 May 2001</p>
<p>Table 69 says this about a_uniq.insert(t):</p>

<blockquote>
inserts t if and only if there is no element in the container with key
equivalent to the key of t. The bool component of the returned pair 
indicates whether the insertion takes place and the iterator component of the
pair points to the element with key equivalent to the key of t.
</blockquote>

<p>The description should be more specific about exactly how the bool component
indicates whether the insertion takes place.</p>
<p><b>Proposed resolution:</b></p>
<p>Change the text in question to</p>

<blockquote>
...The bool component of the returned pair is true if and only if the insertion
takes place...
</blockquote>
<hr>
<a name="317"><h3>317.&nbsp;Instantiation vs. specialization of facets</h3></a><p><b>Section:</b>&nbsp;22 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.localization"> [lib.localization]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;4 May 2001</p>
<p>
The localization section of the standard refers to specializations of
the facet templates as instantiations even though the required facets
are typically specialized rather than explicitly (or implicitly)
instantiated. In the case of ctype&lt;char&gt; and
ctype_byname&lt;char&gt; (and the wchar_t versions), these facets are
actually required to be specialized. The terminology should be
corrected to make it clear that the standard doesn't mandate explicit
instantiation (the term specialization encompasses both explicit
instantiations and specializations).
</p>
<p><b>Proposed resolution:</b></p>
<p>
In the following paragraphs, replace all occurrences of the word
instantiation or instantiations with specialization or specializations,
respectively:
</p>

<blockquote>
22.1.1.1.1, p4, Table 52, 22.2.1.1, p2, 22.2.1.5, p3, 22.2.1.5.1, p5,
22.2.1.5.2, p10, 22.2.2, p2, 22.2.3.1, p1, 22.2.3.1.2, p1, p2 and p3, 
22.2.4.1, p1, 22.2.4.1.2, p1, 22,2,5, p1, 22,2,6, p2, 22.2.6.3.2, p7, and
Footnote 242.
</blockquote>

<p>And change the text in 22.1.1.1.1, p4 from</p>

<blockquote>
    An implementation is required to provide those instantiations
    for facet templates identified as members of a category, and
    for those shown in Table 52:
</blockquote>

<p>to</p>

<blockquote>
    An implementation is required to provide those specializations...
</blockquote>

<p><i>[Nathan will review these changes, and will look for places where
explicit specialization is necessary.]</i></p>

<p><b>Rationale:</b></p>
<p>This is a simple matter of outdated language.  The language to
describe templates was clarified during the standardization process,
but the wording in clause 22 was never updated to reflect that
change.</p>
<hr>
<a name="318"><h3>318.&nbsp;Misleading comment in definition of numpunct_byname</h3></a><p><b>Section:</b>&nbsp;22.2.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.numpunct.byname"> [lib.locale.numpunct.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;12 May 2001</p>
<p>The definition of the numpunct_byname template contains the following
comment:</p>

<pre>    namespace std {
        template &lt;class charT&gt;
        class numpunct_byname : public numpunct&lt;charT&gt; {
    // this class is specialized for char and wchar_t.
        ...
</pre>

<p>There is no documentation of the specializations and it seems
conceivable that an implementation will not explicitly specialize the
template at all, but simply provide the primary template.</p>
<p><b>Proposed resolution:</b></p>
<p>Remove the comment from the text in 22.2.3.2 and from the proposed
resolution of library issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#228">228</a>.</p>
<hr>
<a name="319"><h3>319.&nbsp;Storage allocation wording confuses "Required behavior", "Requires"</h3></a><p><b>Section:</b>&nbsp;18.5.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.single"> [lib.new.delete.single]</a>, 18.5.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.array"> [lib.new.delete.array]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;15 May 2001</p>
<p>The standard specifies 17.3.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.structure.specifications"> [lib.structure.specifications]</a> that "Required
behavior" elements describe "the semantics of a function definition
provided by either the implementation or a C++ program."</p>

<p>The standard specifies 17.3.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.structure.specifications"> [lib.structure.specifications]</a> that "Requires"
elements describe "the preconditions for calling the function."</p>

<p>In the sections noted below, the current wording specifies
"Required Behavior" for what are actually preconditions, and thus
should be specified as "Requires".</p>

<p><b>Proposed resolution:</b></p>

<p>In 18.5.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.single"> [lib.new.delete.single]</a> Para 12 Change:</p>
<blockquote>
  <p>Required behavior: accept a value of ptr that is null or that was
  returned by an earlier call ...</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>Requires: the value of ptr is null or the value returned by an
  earlier call ...</p>
</blockquote>

<p>In 18.5.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.array"> [lib.new.delete.array]</a> Para 11 Change:</p>
<blockquote>
  <p>Required behavior: accept a value of ptr that is null or that was
  returned by an earlier call ...</p>
</blockquote>
<p>to:</p>
<blockquote>
  <p>Requires: the value of ptr is null or the value returned by an
  earlier call ...</p>
</blockquote>

<hr>
<a name="320"><h3>320.&nbsp;list::assign overspecified</h3></a><p><b>Section:</b>&nbsp;23.2.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.deque.cons"> [lib.deque.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;17 May 2001</p>
<p>
Section 23.2.2.1, paragraphs 6-8 specify that list assign (both forms) have
the "effects" of a call to erase followed by a call to insert.
</p>

<p>
I would like to document that implementers have the freedom to implement 
assign by other methods, as long as the end result is the same and the 
exception guarantee is as good or better than the basic guarantee.
</p>

<p>
The motivation for this is to use T's assignment operator to recycle
existing nodes in the list instead of erasing them and reallocating
them with new values.  It is also worth noting that, with careful
coding, most common cases of assign (everything but assignment with
true input iterators) can elevate the exception safety to strong if
T's assignment has a nothrow guarantee (with no extra memory cost).
Metrowerks does this.  However I do not propose that this subtlety be
standardized.  It is a QoI issue.  </p>

<p>Existing practise:
Metrowerks and SGI recycle nodes, Dinkumware and Rogue Wave don't.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change 23.2.2.1/7 from:</p>

<blockquote>
<p>Effects:</p>

<pre>   erase(begin(), end());
   insert(begin(), first, last);
</pre>
</blockquote>

<p>to:</p>

<blockquote>
<p>Effects: Replaces the contents of the list with the range [first, last).</p>
</blockquote>

<p>In 23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a>, in Table 67 (sequence requirements), 
add two new rows:</p>
<pre>      a.assign(i,j)     void      pre: i,j are not iterators into a.
                                  Replaces elements in a with a copy
                                  of [i, j).

      a.assign(n,t)     void      pre: t is not a reference into a.
                                  Replaces elements in a with n copies
                                  of t.
</pre>

<p>Change 23.2.2.1/8 from:</p>

<blockquote>
<p>Effects:</p>
<pre>   erase(begin(), end());
   insert(begin(), n, t);
</pre>
</blockquote>
<p>to:</p>

<blockquote>
<p>Effects: Replaces the contents of the list with n copies of t.</p>
</blockquote>

<p><i>[Redmond: Proposed resolution was changed slightly.  Previous
version made explicit statement about exception safety, which wasn't
consistent with the way exception safety is expressed elsewhere.
Also, the change in the sequence requirements is new.  Without that
change, the proposed resolution would have required that assignment of
a subrange would have to work.  That too would have been
overspecification; it would effectively mandate that assignment use a
temporary.  Howard provided wording.
]</i></p>

<p><i>[Curaçao: Made editorial improvement in wording; changed
"Replaces elements in a with copies of elements in [i, j)."
with "Replaces the elements of a with a copy of [i, j)."
Changes not deemed serious enough to requre rereview.]</i></p>

<hr>
<a name="321"><h3>321.&nbsp;Typo in num_get</h3></a><p><b>Section:</b>&nbsp;22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Kevin Djang&nbsp; <b>Date:</b>&nbsp;17 May 2001</p>
<p>
Section 22.2.2.1.2 at p7 states that "A length specifier is added to
the conversion function, if needed, as indicated in Table 56."
However, Table 56 uses the term "length modifier", not "length
specifier".
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 22.2.2.1.2 at p7, change the text "A length specifier is added ..."
to be "A length modifier is added ..."
</p>
<p><b>Rationale:</b></p>
<p>C uses the term "length modifier".  We should be consistent.</p>
<hr>
<a name="322"><h3>322.&nbsp;iterator and const_iterator should have the same value type</h3></a><p><b>Section:</b>&nbsp;23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;17 May 2001</p>
<p>
It's widely assumed that, if X is a container,
iterator_traits&lt;X::iterator&gt;::value_type and
iterator_traits&lt;X::const_iterator&gt;::value_type should both be
X::value_type.  However, this is nowhere stated.  The language in
Table 65 is not precise about the iterators' value types (it predates
iterator_traits), and could even be interpreted as saying that
iterator_traits&lt;X::const_iterator&gt;::value_type should be "const
X::value_type".
</p>

<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#279">279</a>.</p>
<p><b>Proposed resolution:</b></p>
<p>In Table 65 ("Container Requirements"), change the return type for
X::iterator to "iterator type whose value type is T".  Change the
return type for X::const_iterator to "constant iterator type whose
value type is T".</p>
<p><b>Rationale:</b></p>
<p>
This belongs as a container requirement, rather than an iterator
requirement, because the whole notion of iterator/const_iterator
pairs is specific to containers' iterator.
</p>
<p>
It is existing practice that (for example) 
iterator_traits&lt;list&lt;int&gt;::const_iterator&gt;::value_type
is "int", rather than "const int".  This is consistent with
the way that const pointers are handled: the standard already 
requires that iterator_traits&lt;const int*&gt;::value_type is int.
</p>
<hr>
<a name="324"><h3>324.&nbsp;Do output iterators have value types?</h3></a><p><b>Section:</b>&nbsp;24.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.output.iterators"> [lib.output.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;7 June 2001</p>

<p>Table 73 suggests that output iterators have value types.  It 
requires the expression "*a = t".  Additionally, although Table 73
never lists "a = t" or "X(a) = t" in the "expressions" column, it
contains a note saying that "a = t" and "X(a) = t" have equivalent
(but nowhere specified!) semantics.</p>

<p>According to 24.1/9, t is supposed to be "a value of value type
T":</p>

    <blockquote>
    In the following sections, a and b denote values of X, n denotes a
    value of the difference type Distance, u, tmp, and m denote
    identifiers, r denotes a value of X&amp;, t denotes a value of
    value type T.
    </blockquote>

<p>Two other parts of the standard that are relevant to whether
output iterators have value types:</p>

<ul>
    <li>24.1/1 says "All iterators i support the expression *i,
    resulting in a value of some class, enumeration, or built-in type
    T, called the value type of the iterator".</li>

    <li>
    24.3.1/1, which says "In the case of an output iterator, the types
    iterator_traits&lt;Iterator&gt;::difference_type
    iterator_traits&lt;Iterator&gt;::value_type are both defined as void."
    </li>
</ul>

<p>The first of these passages suggests that "*i" is supposed to
return a useful value, which contradicts the note in 24.1.2/2 saying
that the only valid use of "*i" for output iterators is in an
expression of the form "*i = t".  The second of these passages appears
to contradict Table 73, because it suggests that "*i"'s return value
should be void.  The second passage is also broken in the case of a an
iterator type, like non-const pointers, that satisfies both the output
iterator requirements and the forward iterator requirements.</p>

<p>What should the standard say about <tt>*i</tt>'s return value when
i is an output iterator, and what should it say about that t is in the
expression "*i = t"?  Finally, should the standard say anything about
output iterators' pointer and reference types?</p>

<p><b>Proposed resolution:</b></p>
<p>24.1 p1, change</p>

<blockquote>
<p>All iterators <tt>i</tt> support the expression <tt>*i</tt>, resulting
in a value of some class, enumeration, or built-in type <tt>T</tt>,
called the value type of the iterator.</p>
</blockquote>

<p>to</p>

<blockquote>
<p>All input iterators <tt>i</tt> support the expression <tt>*i</tt>,
resulting in a value of some class, enumeration, or built-in type
<tt>T</tt>, called the value type of the iterator. All output
iterators support the expression <tt>*i = o</tt> where <tt>o</tt> is a
value of some type that is in the set of types that are <i>writable</i> to
the particular iterator type of <tt>i</tt>.
</p>
</blockquote>

<p>24.1 p9, add</p>

<blockquote>
<p><tt>o</tt> denotes a value of some type that is writable to the
output iterator.
</p>
</blockquote>

<p>Table 73, change</p>

<blockquote>
<pre>*a = t
</pre>
</blockquote>

<p>to</p>

<blockquote>
<pre>*r = o
</pre>
</blockquote>

<p>and change</p>

<blockquote>
<pre>*r++ = t
</pre>
</blockquote>

<p>to</p>

<blockquote>
<pre>*r++ = o
</pre>
</blockquote>

<p><i>[post-Redmond: Jeremy provided wording]</i></p>

<p><b>Rationale:</b></p>
<p>The LWG considered two options: change all of the language that
seems to imply that output iterators have value types, thus making it
clear that output iterators have no value types, or else define value
types for output iterator consistently.  The LWG chose the former
option, because it seems clear that output iterators were never
intended to have value types.  This was a deliberate design decision,
and any language suggesting otherwise is simply a mistake.</p>

<p>A future revision of the standard may wish to revisit this design
decision.</p>
<hr>
<a name="325"><h3>325.&nbsp;Misleading text in moneypunct&lt;&gt;::do_grouping</h3></a><p><b>Section:</b>&nbsp;22.2.6.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.moneypunct.virtuals"> [lib.locale.moneypunct.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;02 Jul 2001</p>
<p>The Returns clause in 22.2.6.3.2, p3 says about
moneypunct&lt;charT&gt;::do_grouping()
</p>

<blockquote>
    Returns: A pattern defined identically as the result of
    numpunct&lt;charT&gt;::do_grouping().241)
</blockquote>

<p>Footnote 241 then reads</p>

<blockquote>
    This is most commonly the value "\003" (not "3").
</blockquote>

<p>
The returns clause seems to imply that the two member functions must
return an identical value which in reality may or may not be true,
since the facets are usually implemented in terms of struct std::lconv
and return the value of the grouping and mon_grouping, respectively.
The footnote also implies that the member function of the moneypunct
facet (rather than the overridden virtual functions in moneypunct_byname)
most commonly return "\003", which contradicts the C standard which
specifies the value of "" for the (most common) C locale.
</p>

<p><b>Proposed resolution:</b></p>
<p>Replace the text in Returns clause in 22.2.6.3.2, p3 with the following:</p>

<blockquote>
    Returns: A pattern defined identically as, but not necessarily
    equal to, the result of numpunct&lt;charT&gt;::do_grouping().241)
</blockquote>

<p>and replace the text in Footnote 241 with the following:</p>

<blockquote>
    To specify grouping by 3s the value is "\003", not "3".
</blockquote>
<p><b>Rationale:</b></p>
<p>
The fundamental problem is that the description of the locale facet
virtuals serves two purposes: describing the behavior of the base
class, and describing the meaning of and constraints on the behavior
in arbitrary derived classes.  The new wording makes that separation a
little bit clearer.  The footnote (which is nonnormative) is not
supposed to say what the grouping is in the "C" locale or in any other
locale. It is just a reminder that the values are interpreted as small
integers, not ASCII characters.
</p>
<hr>
<a name="327"><h3>327.&nbsp;Typo in time_get facet in table 52</h3></a><p><b>Section:</b>&nbsp;22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Tiki Wan&nbsp; <b>Date:</b>&nbsp;06 Jul 2001</p>
<p>The <tt>wchar_t</tt> versions of <tt>time_get</tt> and
<tt>time_get_byname</tt> are listed incorrectly in table 52,
required instantiations.  In both cases the second template
parameter is given as OutputIterator.  It should instead be
InputIterator, since these are input facets.</p>
<p><b>Proposed resolution:</b></p>
<p>
In table 52, required instantiations, in 
22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>, change</p>
<pre>    time_get&lt;wchar_t, OutputIterator&gt;
    time_get_byname&lt;wchar_t, OutputIterator&gt;
</pre>
<p>to</p>
<pre>    time_get&lt;wchar_t, InputIterator&gt;
    time_get_byname&lt;wchar_t, InputIterator&gt;
</pre>

<p><i>[Redmond: Very minor change in proposed resolution.  Original had
a typo, wchart instead of wchar_t.]</i></p>

<hr>
<a name="328"><h3>328.&nbsp;Bad sprintf format modifier in money_put&lt;&gt;::do_put()</h3></a><p><b>Section:</b>&nbsp;22.2.6.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.money.put.virtuals"> [lib.locale.money.put.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;07 Jul 2001</p>
<p>The sprintf format string , "%.01f" (that's the digit one), in the
description of the do_put() member functions of the money_put facet in
22.2.6.2.2, p1 is incorrect. First, the f format specifier is wrong
for values of type long double, and second, the precision of 01
doesn't seem to make sense. What was most likely intended was
"%.0Lf"., that is a precision of zero followed by the L length
modifier.</p>
<p><b>Proposed resolution:</b></p>
<p>Change the format string to "%.0Lf".</p>
<p><b>Rationale:</b></p>
<p>Fixes an obvious typo</p>
<hr>
<a name="329"><h3>329.&nbsp;vector capacity, reserve and reallocation</h3></a><p><b>Section:</b>&nbsp;23.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.priority.queue"> [lib.priority.queue]</a>, 23.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.stack"> [lib.stack]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Anthony Williams&nbsp; <b>Date:</b>&nbsp;13 Jul 2001</p>
<p>
There is an apparent contradiction about which circumstances can cause
a reallocation of a vector in Section 23.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.priority.queue"> [lib.priority.queue]</a> and
section 23.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.stack"> [lib.stack]</a>.
</p>

<p>23.2.4.2p5 says:</p>
<blockquote>
Notes: Reallocation invalidates all the references, pointers, and iterators
referring to the elements in the sequence. It is guaranteed that no
reallocation takes place during insertions that happen after a call to
reserve() until the time when an insertion would make the size of the vector
greater than the size specified in the most recent call to reserve().
</blockquote>

<p>Which implies if I do</p>

<pre>  std::vector&lt;int&gt; vec;
  vec.reserve(23);
  vec.reserve(0);
  vec.insert(vec.end(),1);
</pre>

<p>then the implementation may reallocate the vector for the insert,
as the size specified in the previous call to reserve was zero.</p>

<p>However, the previous paragraphs (23.2.4.2, p1-2) state:</p>
<blockquote>
<p>
(capacity) Returns: The total number of elements the vector
can hold without requiring reallocation
</p>
<p>
...After reserve(), capacity() is greater or equal to the
argument of reserve if reallocation happens; and equal to the previous value
of capacity() otherwise...
</p>
</blockquote>

<p>
This implies that vec.capacity() is still 23, and so the insert()
should not require a reallocation, as vec.size() is 0. This is backed
up by 23.2.4.3p1:
</p>
<blockquote>
(insert) Notes: Causes reallocation if the new size is greater than the old
capacity.
</blockquote>

<p>
Though this doesn't rule out reallocation if the new size is less
than the old capacity, I think the intent is clear.
</p>

<p><b>Proposed resolution:</b></p>
<p>Change the wording of 23.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.priority.queue"> [lib.priority.queue]</a> paragraph 5 to:</p>

<blockquote>
Notes: Reallocation invalidates all the references, pointers, and
iterators referring to the elements in the sequence. It is guaranteed
that no reallocation takes place during insertions that happen after a
call to reserve() until the time when an insertion would make the size
of the vector greater than the value of capacity().
</blockquote>

<p><i>[Redmond: original proposed resolution was modified slightly.  In
the original, the guarantee was that there would be no reallocation
until the size would be greater than the value of capacity() after the
most recent call to reserve().  The LWG did not believe that the
"after the most recent call to reserve()" added any useful
information.]</i></p>

<p><b>Rationale:</b></p>
<p>There was general agreement that, when reserve() is called twice in
succession and the argument to the second invocation is smaller than
the argument to the first, the intent was for the second invocation to
have no effect.  Wording implying that such cases have an effect on
reallocation guarantees was inadvertant.</p>
<hr>
<a name="331"><h3>331.&nbsp;bad declaration of destructor for ios_base::failure</h3></a><p><b>Section:</b>&nbsp;27.4.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios::failure"> [lib.ios::failure]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;PremAnand M. Rao&nbsp; <b>Date:</b>&nbsp;23 Aug 2001</p>
<p>
With the change in 17.4.4.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.res.on.exception.handling"> [lib.res.on.exception.handling]</a> to state
   "An implementation may strengthen the exception-specification for a 
    non-virtual function by removing listed exceptions."
(issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#119">119</a>)
and the following declaration of ~failure() in ios_base::failure
</p>
<pre>    namespace std {
       class ios_base::failure : public exception {
       public:
           ...
           virtual ~failure();
           ...
       };
     }
</pre>
<p>the class failure cannot be implemented since in 18.6.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.type.info"> [lib.type.info]</a> the destructor of class exception has an empty
exception specification:</p>
<pre>    namespace std {
       class exception {
       public:
         ...
         virtual ~exception() throw();
         ...
       };
     }
</pre>
<p><b>Proposed resolution:</b></p>
<p>Remove the declaration of ~failure().</p>
<p><b>Rationale:</b></p>
<p>The proposed resolution is consistent with the way that destructors
of other classes derived from <tt>exception</tt> are handled.</p>
<hr>
<a name="333"><h3>333.&nbsp;does endl imply synchronization with the device?</h3></a><p><b>Section:</b>&nbsp;27.6.2.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.manip"> [lib.ostream.manip]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;PremAnand M. Rao&nbsp; <b>Date:</b>&nbsp;27 Aug 2001</p>
<p>A footnote in 27.6.2.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.manip"> [lib.ostream.manip]</a> states:</p>
<blockquote>
    [Footnote: The effect of executing cout &lt;&lt; endl is to insert a 
     newline character in the output sequence controlled by cout, then 
     synchronize it with any external file with which it might be 
     associated. --- end foonote]
</blockquote>

<p>
Does the term "file" here refer to the external device?
This leads to some implementation ambiguity on systems with fully 
buffered files where a newline does not cause a flush to the device.
</p>

<p>
Choosing to sync with the device leads to significant performance
penalties for each call to endl, while not sync-ing leads to
errors under special circumstances.
</p>

<p>
I could not find any other statement that explicitly defined
the behavior one way or the other.
</p>
<p><b>Proposed resolution:</b></p>
<p>Remove footnote 300 from section 27.6.2.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.manip"> [lib.ostream.manip]</a>.</p>
<p><b>Rationale:</b></p>
<p>We already have normative text saying what <tt>endl</tt> does: it
inserts a newline character and calls <tt>flush</tt>.  This footnote
is at best redundant, at worst (as this issue says) misleading,
because it appears to make promises about what <tt>flush</tt>
does.</p>
<hr>
<a name="334"><h3>334.&nbsp;map::operator[] specification forces inefficient implementation</h3></a><p><b>Section:</b>&nbsp;23.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map.access"> [lib.map.access]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andrea Griffini&nbsp; <b>Date:</b>&nbsp;02 Sep 2001</p>
<p>
The current standard describes map::operator[] using a
code example. That code example is however quite
inefficient because it requires several useless copies
of both the passed key_type value and of default
constructed mapped_type instances.
My opinion is that was not meant by the comitee to
require all those temporary copies. 
</p>

<p>Currently map::operator[] behaviour is specified as: </p>
<pre>  Returns:
    (*((insert(make_pair(x, T()))).first)).second.
</pre>
  
<p>
This specification however uses make_pair that is a
template function of which parameters in this case
will be deduced being of type const key_type&amp; and
const T&amp;. This will create a pair&lt;key_type,T&gt; that
isn't the correct type expected by map::insert so
another copy will be required using the template
conversion constructor available in pair to build
the required pair&lt;const key_type,T&gt; instance.
</p>

<p>If we consider calling of key_type copy constructor
and mapped_type default constructor and copy
constructor as observable behaviour (as I think we
should) then the standard is in this place requiring
two copies of a key_type element plus a default
construction and two copy construction of a mapped_type
(supposing the addressed element is already present
in the map; otherwise at least another copy
construction for each type). 
</p>

<p>A simple (half) solution would be replacing the description with:</p>
<pre>  Returns:
    (*((insert(value_type(x, T()))).first)).second.
</pre>

<p>This will remove the wrong typed pair construction that
requires one extra copy of both key and value.</p>

<p>However still the using of map::insert requires temporary
objects while the operation, from a logical point of view,
doesn't require any. </p>

<p>I think that a better solution would be leaving free an
implementer to use a different approach than map::insert
that, because of its interface, forces default constructed
temporaries and copies in this case.
The best solution in my opinion would be just requiring
map::operator[] to return a reference to the mapped_type
part of the contained element creating a default element
with the specified key if no such an element is already
present in the container. Also a logarithmic complexity
requirement should be specified for the operation.
</p>

<p>
This would allow library implementers to write alternative
implementations not using map::insert and reaching optimal
performance in both cases of the addressed element being
present or absent from the map (no temporaries at all and
just the creation of a new pair inside the container if
the element isn't present).
Some implementer has already taken this option but I think
that the current wording of the standard rules that as
non-conforming. 
</p>

<p><b>Proposed resolution:</b></p>

<p>
Replace 23.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map.access"> [lib.map.access]</a> paragraph 1 with
</p>
<blockquote>
<p>
-1- Effects:  If there is no key equivalent to x in the map, inserts 
value_type(x, T()) into the map.
</p>
<p>
-2- Returns: A reference to the mapped_type corresponding to x in *this.
</p>
<p>
-3- Complexity: logarithmic.
</p>
</blockquote>

<p><i>[This is the second option mentioned above.  Howard provided
wording.  We may also wish to have a blanket statement somewhere in
clause 17 saying that we do not intend the semantics of sample code
fragments to be interpreted as specifing exactly how many copies are
made.  See issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#98">98</a> for a similar problem.]</i></p>

<p><b>Rationale:</b></p>
<p>
This is the second solution described above; as noted, it is
consistent with existing practice.
</p>

<p>Note that we now need to specify the complexity explicitly, because
we are no longer defining <tt>operator[]</tt> in terms of
<tt>insert</tt>.</p>
<hr>
<a name="335"><h3>335.&nbsp;minor issue with char_traits, table 37</h3></a><p><b>Section:</b>&nbsp;21.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.char.traits.require"> [lib.char.traits.require]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andy Sawyer&nbsp; <b>Date:</b>&nbsp;06 Sep 2001</p>
<p>
Table 37, in 21.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.char.traits.require"> [lib.char.traits.require]</a>, descibes char_traits::assign
as:
</p>
<pre>  X::assign(c,d)   assigns c = d.
</pre>

<p>And para 1 says:</p>

<blockquote>
 [...] c and d denote values of type CharT [...]
</blockquote>

<p>
Naturally, if c and d are <i>values</i>, then the assignment is
(effectively) meaningless. It's clearly intended that (in the case of
assign, at least), 'c' is intended to be a reference type.
</p>

<p>I did a quick survey of the four implementations I happened to have
lying around, and sure enough they all have signatures:</p>
<pre>    assign( charT&amp;, const charT&amp; );
</pre>

<p>(or the equivalent). It's also described this way in Nico's book.
(Not to mention the synopses of char_traits&lt;char&gt; in 21.1.3.1
and char_traits&lt;wchar_t&gt; in 21.1.3.2...)
</p>
<p><b>Proposed resolution:</b></p>
<p>Add the following to 21.1.1 para 1:</p>
<blockquote>
 r denotes an lvalue of CharT
</blockquote>

<p>and change the description of assign in the table to:</p>
<pre>  X::assign(r,d)   assigns r = d
</pre>
<hr>
<a name="336"><h3>336.&nbsp;Clause 17 lack of references to deprecated headers</h3></a><p><b>Section:</b>&nbsp;17 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.library"> [lib.library]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Detlef Vollmann&nbsp; <b>Date:</b>&nbsp;05 Sep 2001</p>
<p>From c++std-edit-873:</p>

<p>17.4.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.headers"> [lib.headers]</a>, Table 11.  In this table, the header
&lt;strstream&gt; is missing.</p>

<p>This shows a general problem: The whole clause 17 refers quite
often to clauses 18 through 27, but D.7 is also a part of the standard
library (though a deprecated one).</p>

<p><b>Proposed resolution:</b></p>

<p>To 17.4.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.headers"> [lib.headers]</a> Table 11, C++ Library Headers, add
"&lt;strstream&gt;".</p>

<p>In the following places, change "clauses 17 through 27" to "clauses
17 through 27 and Annex D":</p>

<ul>
<li>1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/intro.html#intro.refs"> [intro.refs]</a> Normative references/1/footnote 1</li>
<li>1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/intro.html#intro.defs"> [intro.defs]</a> Definitions/1</li>
<li>7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/dcl.html#dcl.dcl"> [dcl.dcl]</a> Library introduction/9</li>
<li>17.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.description"> [lib.description]</a> Method of description (Informative)/1</li>
<li>17.3.2.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.character.seq"> [lib.character.seq]</a> Character sequences/1/bullet 2</li>
<li>17.3.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.functions.within.classes"> [lib.functions.within.classes]</a> Functions within classes/1</li>
<li>17.3.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.objects.within.classes"> [lib.objects.within.classes]</a> Private members/1/(2 places)</li>
<li>17.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.requirements"> [lib.requirements]</a> Library-wide requirements/1</li>
<li>17.4.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.headers"> [lib.headers]</a> Headers/4</li>
<li>17.4.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.replacement.functions"> [lib.replacement.functions]</a> Replacement functions/1</li>
<li>17.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.global.functions"> [lib.global.functions]</a> Global or non-member functions/2</li>
<li>17.4.4.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.protection.within.classes"> [lib.protection.within.classes]</a> Protection within classes/1</li>
</ul>


<hr>
<a name="337"><h3>337.&nbsp;replace_copy_if's template parameter should be InputIterator</h3></a><p><b>Section:</b>&nbsp;25.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.replace"> [lib.alg.replace]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Detlef Vollmann&nbsp; <b>Date:</b>&nbsp;07 Sep 2001</p>
<p>From c++std-edit-876:</p>

<p>
In section 25.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.replace"> [lib.alg.replace]</a> before p4: The name of the first
parameter of template replace_copy_if should be "InputIterator"
instead of "Iterator".  According to 17.3.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.type.descriptions"> [lib.type.descriptions]</a> p1 the
parameter name conveys real normative meaning.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change <tt>Iterator</tt> to <tt>InputIterator</tt>.</p>
<hr>
<a name="338"><h3>338.&nbsp; is whitespace allowed between `-' and a digit?</h3></a><p><b>Section:</b>&nbsp;22.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.categories"> [lib.locale.categories]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;17 Sep 2001</p>
<p>
From Stage 2 processing in 22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>, p8 and 9 (the
original text or the text corrected by the proposed resolution of
issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#221">221</a>) it seems clear that no whitespace is allowed
within a number, but 22.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.numpunct"> [lib.locale.numpunct]</a>, p2, which gives the
format for integer and floating point values, says that whitespace is
optional between a plusminus and a sign.
</p>

<p>
The text needs to be clarified to either consistently allow or
disallow whitespace between a plusminus and a sign. It might be
worthwhile to consider the fact that the C library stdio facility does
not permit whitespace embedded in numbers and neither does the C or
C++ core language (the syntax of integer-literals is given in 2.13.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lex.html#lex.icon"> [lex.icon]</a>, that of floating-point-literals in 2.13.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lex.html#lex.fcon"> [lex.fcon]</a> of the C++ standard).
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the first part of 22.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.numpunct"> [lib.locale.numpunct]</a> paragraph 2 from:</p>
<blockquote>
<p>
The syntax for number formats is as follows, where <tt>digit</tt>
represents the radix set specified by the <tt>fmtflags</tt> argument
value, <tt>whitespace</tt> is as determined by the facet
<tt>ctype&lt;charT&gt;</tt> (22.2.1.1), and <tt>thousands-sep</tt> and
<tt>decimal-point</tt> are the results of corresponding
<tt>numpunct&lt;charT&gt;</tt> members.  Integer values have the
format:
</p>
<pre>  integer   ::= [sign] units
  sign      ::= plusminus [whitespace]
  plusminus ::= '+' | '-'
  units     ::= digits [thousands-sep units]
  digits    ::= digit [digits]
</pre>
</blockquote>
<p>to:</p>
<blockquote>
<p>
The syntax for number formats is as follows, where <tt>digit</tt>
represents the radix set specified by the <tt>fmtflags</tt> argument
value, and <tt>thousands-sep</tt> and <tt>decimal-point</tt> are the
results of corresponding <tt>numpunct&lt;charT&gt;</tt> members.
Integer values have the format:
</p>
<pre>  integer   ::= [sign] units
  sign      ::= plusminus
  plusminus ::= '+' | '-'
  units     ::= digits [thousands-sep units]
  digits    ::= digit [digits]
</pre>
</blockquote>
<p><b>Rationale:</b></p>
<p>It's not clear whether the format described in 22.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.numpunct"> [lib.locale.numpunct]</a> paragraph 2 has any normative weight: nothing in the
standard says how, or whether, it's used.  However, there's no reason
for it to differ gratuitously from the very specific description of
numeric processing in 22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>.  The proposed
resolution removes all mention of "whitespace" from that format.</p>
<hr>
<a name="339"><h3>339.&nbsp;definition of bitmask type restricted to clause 27</h3></a><p><b>Section:</b>&nbsp;22.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.category.ctype"> [lib.category.ctype]</a>, 17.3.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.bitmask.types"> [lib.bitmask.types]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;17 September 2001</p>
<p>
The ctype_category::mask type is declared to be an enum in 22.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.category.ctype"> [lib.category.ctype]</a> with p1 then stating that it is a bitmask type, most
likely referring to the definition of bitmask type in 17.3.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.bitmask.types"> [lib.bitmask.types]</a>, p1. However, the said definition only applies to
clause 27, making the reference in 22.2.1 somewhat dubious.
</p>
<p><b>Proposed resolution:</b></p>
<p>Clarify 17.3.2.1.2, p1 by changing the current text from</p>
    <blockquote>
    Several types defined in clause 27 are bitmask types. Each bitmask type
    can be implemented as an enumerated type that overloads certain operators,
    as an integer type, or as a bitset (23.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.template.bitset"> [lib.template.bitset]</a>).
    </blockquote>
<p>to read</p>
    <blockquote>
    Several types defined in clauses lib.language.support through 
    lib.input.output and Annex D are bitmask types. Each bitmask type can
    be implemented as an enumerated type that overloads certain operators,
    as an integer  type, or as a bitset (lib.template.bitset).
    </blockquote>

<p>
Additionally, change the definition in 22.2.1 to adopt the same
convention as in clause 27 by replacing the existing text with the
following (note, in particluar, the cross-reference to 17.3.2.1.2 in
22.2.1, p1):
</p>

<blockquote>
<p>22.2.1 The ctype category [lib.category.ctype]</p>
<pre>namespace std {
    class ctype_base {
    public:
        typedef <b><i>T</i></b> mask;

        // numeric values are for exposition only.
        static const mask space = 1 &lt;&lt; 0;
        static const mask print = 1 &lt;&lt; 1;
        static const mask cntrl = 1 &lt;&lt; 2;
        static const mask upper = 1 &lt;&lt; 3;
        static const mask lower = 1 &lt;&lt; 4;
        static const mask alpha = 1 &lt;&lt; 5;
        static const mask digit = 1 &lt;&lt; 6;
        static const mask punct = 1 &lt;&lt; 7;
        static const mask xdigit = 1 &lt;&lt; 8;
        static const mask alnum = alpha | digit;
        static const mask graph = alnum | punct;
    };
}
</pre>

<p>The type <tt>mask</tt> is a bitmask type (17.3.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.bitmask.types"> [lib.bitmask.types]</a>).</p>
</blockquote>

<p><i>[Curaçao: The LWG notes that T above should be bold-italics to be
consistent with the rest of the standard.]</i></p>

<hr>
<a name="340"><h3>340.&nbsp;interpretation of <tt>has_facet&lt;Facet&gt;(loc)</tt>
</h3></a><p><b>Section:</b>&nbsp;22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;18 Sep 2001</p>
<p>
It's unclear whether 22.1.1.1.1, p3 says that
<tt>has_facet&lt;Facet&gt;(loc)</tt> returns true for any <tt>Facet</tt>
from Table 51 or whether it includes Table 52 as well:
</p>

<blockquote>
For any locale <tt>loc</tt> either constructed, or returned by
locale::classic(), and any facet <tt>Facet</tt> that is a member of a
standard category, <tt>has_facet&lt;Facet&gt;(loc)</tt> is true. Each
locale member function which takes a <tt>locale::category</tt>
argument operates on the corresponding set of facets.
</blockquote>

<p>
It seems that it comes down to which facets are considered to be members of a
standard category. Intuitively, I would classify all the facets in Table 52 as
members of their respective standard categories, but there are an unbounded set
of them...
</p>

<p>
The paragraph implies that, for instance, <tt>has_facet&lt;num_put&lt;C,
OutputIterator&gt; &gt;(loc)</tt> must always return true. I don't think that's
possible. If it were, then <tt>use_facet&lt;num_put&lt;C, OutputIterator&gt;
&gt;(loc)</tt> would have to return a reference to a distinct object for each
valid specialization of <tt>num_put&lt;C, OutputIteratory&gt;</tt>, which is
clearly impossible.
</p>

<p>
On the other hand, if none of the facets in Table 52 is a member of a standard
category then none of the locale member functions that operate on entire
categories of facets will work properly.
</p>

<p>
It seems that what p3 should mention that it's required (permitted?)
to hold only for specializations of <tt>Facet</tt> from Table 52 on
<tt>C</tt> from the set { <tt>char</tt>, <tt>wchar_t</tt> }, and
<tt>InputIterator</tt> and <tt>OutputIterator</tt> from the set of
{
{i,o}<tt>streambuf_iterator</tt>&lt;{<tt>char</tt>,<tt>wchar_t</tt>}<tt>&gt;</tt>
}.
</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>, paragraph 3, change
"that is a member of a standard category" to "shown in Table 51".</p>
<p><b>Rationale:</b></p>
<p>The facets in Table 52 are an unbounded set.  Locales should not be
required to contain an infinite number of facets.</p> 

<p>It's not necessary to talk about which values of InputIterator and
OutputIterator must be supported.  Table 51 already contains a
complete list of the ones we need.</p>
<hr>
<a name="341"><h3>341.&nbsp;Vector reallocation and swap</h3></a><p><b>Section:</b>&nbsp;23.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.priority.queue"> [lib.priority.queue]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Anthony Williams&nbsp; <b>Date:</b>&nbsp;27 Sep 2001</p>
<p>It is a common idiom to reduce the capacity of a vector by swapping it with
an empty one:</p>
<pre>  std::vector&lt;SomeType&gt; vec;
  // fill vec with data
  std::vector&lt;SomeType&gt;().swap(vec);
  // vec is now empty, with minimal capacity
</pre>

<p>However, the wording of 23.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.priority.queue"> [lib.priority.queue]</a>paragraph 5 prevents
the capacity of a vector being reduced, following a call to
reserve(). This invalidates the idiom, as swap() is thus prevented
from reducing the capacity. The proposed wording for issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#329">329</a> does not affect this.  Consequently, the example above
requires the temporary to be expanded to cater for the contents of
vec, and the contents be copied across. This is a linear-time
operation.</p>

<p>However, the container requirements state that swap must have constant
complexity (23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> note to table 65).</p>

<p>This is an important issue, as reallocation affects the validity of
references and iterators.</p>

<p>If the wording of 23.2.4.2p5 is taken to be the desired intent, then
references and iterators remain valid after a call to swap, if they refer to
an element before the new end() of the vector into which they originally
pointed, in which case they refer to the element at the same index position.
Iterators and references that referred to an element whose index position
was beyond the new end of the vector are invalidated.</p>

<p>If the note to table 65 is taken as the desired intent, then there are two
possibilities with regard to iterators and references:</p>

<ol>
<li>All Iterators and references into both vectors are invalidated.</li>
<li>Iterators and references into either vector remain valid, and remain
pointing to the same element. Consequently iterators and references that
referred to one vector now refer to the other, and vice-versa.</li>
</ol>
<p><b>Proposed resolution:</b></p>
<p>Add a new paragraph after 23.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.priority.queue"> [lib.priority.queue]</a> paragraph 5:</p>
<blockquote>
<pre>  void swap(vector&lt;T,Allocator&gt;&amp; x);
</pre>
<p><b>Effects:</b> Exchanges the contents and capacity() of <tt>*this</tt>
with that of <tt>x</tt>.</p>
<p><b>Complexity:</b> Constant time.</p>
</blockquote>

<p><i>[This solves the problem reported for this issue.  We may also
have a problem with a circular definition of swap() for other
containers.]</i></p>

<p><b>Rationale:</b></p>
<p>
swap should be constant time.  The clear intent is that it should just
do pointer twiddling, and that it should exchange all properties of
the two vectors, including their reallocation guarantees.
</p>
<hr>
<a name="345"><h3>345.&nbsp;type tm in &lt;cwchar&gt;</h3></a><p><b>Section:</b>&nbsp;21.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.c.strings"> [lib.c.strings]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Clark Nelson&nbsp; <b>Date:</b>&nbsp;19 Oct 2001</p>
<p>
C99, and presumably amendment 1 to C90, specify that &lt;wchar.h&gt;
declares struct tm as an incomplete type. However, table 48 in 21.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.c.strings"> [lib.c.strings]</a> does not mention the type tm as being declared in
&lt;cwchar&gt;. Is this omission intentional or accidental?
</p>
<p><b>Proposed resolution:</b></p>
<p>In section 21.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.c.strings"> [lib.c.strings]</a>, add "tm" to table 48.</p>
<hr>
<a name="346"></a><h3><a name="346">346.&nbsp;Some iterator member functions should be const</a></h3><p><b>Section:</b>&nbsp;24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Jeremy Siek&nbsp; <b>Date:</b>&nbsp;20 Oct 2001</p>
<p>Iterator member functions and operators that do not change the state
of the iterator should be defined as const member functions or as
functions that take iterators either by const reference or by
value. The standard does not explicitly state which functions should
be const.  Since this a fairly common mistake, the following changes
are suggested to make this explicit.</p>

<p>The tables almost indicate constness properly through naming: r
for non-const and a,b for const iterators. The following changes
make this more explicit and also fix a couple problems.</p>
<p><b>Proposed resolution:</b></p>
<p>In 24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a> Change the first section of p9 from
"In the following sections, a and b denote values of X..." to
"In the following sections, a and b denote values of type const X...".</p>

<p>In Table 73, change</p>
<pre>    a-&gt;m   U&amp;         ...
</pre>

<p>to</p>

<pre>    a-&gt;m   const U&amp;   ...
    r-&gt;m   U&amp;         ...
</pre>

<p>In Table 73 expression column, change</p>

<pre>    *a = t
</pre>

<p>to</p>

<pre>    *r = t
</pre>

<p><i>[Redmond: The container requirements should be reviewed to see if
the same problem appears there.]</i></p>

<hr>
<a name="347"><h3>347.&nbsp;locale::category and bitmask requirements</h3></a><p><b>Section:</b>&nbsp;22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;P.J. Plauger, Nathan Myers&nbsp; <b>Date:</b>&nbsp;23 Oct 2001</p>
<p>
In 22.1.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.category"> [lib.locale.category]</a> paragraph 1, the category members
are described as bitmask elements.  In fact, the bitmask requirements
in 17.3.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.bitmask.types"> [lib.bitmask.types]</a> don't seem quite right: <tt>none</tt>
and <tt>all</tt> are bitmask constants, not bitmask elements.</p>

<p>In particular, the requirements for <tt>none</tt> interact poorly
with the requirement that the LC_* constants from the C library must
be recognizable as C++ locale category constants.  LC_* values should
not be mixed with these values to make category values.</p>

<p>We have two options for the proposed resolution.  Informally:
option 1 removes the requirement that LC_* values be recognized as
category arguments.  Option 2 changes the category type so that this
requirement is implementable, by allowing <tt>none</tt> to be some
value such as 0x1000 instead of 0.</p>

<p>Nathan writes: "I believe my proposed resolution [Option 2] merely
re-expresses the status quo more clearly, without introducing any
changes beyond resolving the DR.</p>

<p><b>Proposed resolution:</b></p>
<p>Replace the first two paragraphs of 22.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.types"> [lib.locale.types]</a> with:</p>
<blockquote>
<pre>    typedef int category;
</pre>

<p>Valid category values include the <tt>locale</tt> member bitmask
elements <tt>collate</tt>, <tt>ctype</tt>, <tt>monetary</tt>,
<tt>numeric</tt>, <tt>time</tt>, and <tt>messages</tt>, each of which
represents a single locale category. In addition, <tt>locale</tt> member
bitmask constant <tt>none</tt> is defined as zero and represents no
category. And locale member bitmask constant <tt>all</tt> is defined such that
the expression</p>
<pre>    (collate | ctype | monetary | numeric | time | messages | all) == all
</pre>
<p>
is <tt>true</tt>, and represents the union of all categories.  Further
the expression <tt>(X | Y)</tt>, where <tt>X</tt> and <tt>Y</tt> each
represent a single category, represents the union of the two
categories.
</p>

<p>
<tt>locale</tt> member functions expecting a <tt>category</tt>
argument require one of the <tt>category</tt> values defined above, or
the union of two or more such values. Such a <tt>category</tt>
argument identifies a set of locale categories. Each locale category,
in turn, identifies a set of locale facets, including at least those
shown in Table 51:
</p>
</blockquote>
<p><i>[Curaçao: need input from locale experts.]</i></p>

<p><b>Rationale:</b></p>

<p>The LWG considered, and rejected, an alternate proposal (described
  as "Option 2" in the discussion).  The main reason for rejecting it
  was that library implementors were concerened about implementation
  difficult, given that getting a C++ library to work smoothly with a
  separately written C library is already a delicate business.  Some
  library implementers were also concerned about the issue of adding
  extra locale categories.</p>

<blockquote>
<p><b>Option 2:</b> <br>
Replace the first paragraph of 22.1.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.types"> [lib.locale.types]</a> with:</p>
<blockquote>
<p>
Valid category values include the enumerated values.  In addition, the
result of applying commutative operators | and &amp; to any two valid 
values is valid, and results in the setwise union and intersection, 
respectively, of the argument categories.  The values <tt>all</tt> and 
<tt>none</tt> are defined such that for any valid value <tt>cat</tt>, the
expressions <tt>(cat | all == all)</tt>, <tt>(cat &amp; all == cat)</tt>,
<tt>(cat | none == cat)</tt> and <tt>(cat &amp; none == none)</tt> are 
true.  For non-equal values <tt>cat1</tt> and <tt>cat2</tt> of the
remaining enumerated values, <tt>(cat1 &amp; cat2 == none)</tt> is true.
For any valid categories <tt>cat1</tt> and <tt>cat2</tt>, the result
of <tt>(cat1 &amp; ~cat2)</tt> is valid, and equals the setwise union of 
those categories found in <tt>cat1</tt> but not found in <tt>cat2</tt>.
[Footnote: it is not required that <tt>all</tt> equal the setwise union
of the other enumerated values; implementations may add extra categories.]
</p>
</blockquote>
</blockquote>
<hr>
<a name="349"><h3>349.&nbsp;Minor typographical error in ostream_iterator</h3></a><p><b>Section:</b>&nbsp;24.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.ostream.iterator"> [lib.ostream.iterator]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andy Sawyer&nbsp; <b>Date:</b>&nbsp;24 Oct 2001</p>
<p>24.5.2 [lib.ostream.iterator] states:</p>
<pre>    [...]

    private:
    // basic_ostream&lt;charT,traits&gt;* out_stream; exposition only
    // const char* delim; exposition only
</pre>

<p>Whilst it's clearly marked "exposition only", I suspect 'delim'
should be of type 'const charT*'.</p>
<p><b>Proposed resolution:</b></p>
<p>
In 24.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.ostream.iterator"> [lib.ostream.iterator]</a>, replace <tt>const char* delim</tt> with
<tt>const charT* delim</tt>.
</p>
<hr>
<a name="352"><h3>352.&nbsp;missing fpos requirements</h3></a><p><b>Section:</b>&nbsp;21.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.char.traits.typedefs"> [lib.char.traits.typedefs]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;2 Dec 2001</p>
<p>
<i>(1)</i>
There are no requirements on the <tt>stateT</tt> template parameter of
<tt>fpos</tt> listed in 27.4.3. The interface appears to require that
the type be at least Assignable and CopyConstructible (27.4.3.1, p1),
and I think also DefaultConstructible (to implement the operations in
Table 88).
</p>
<p>
21.1.2, p3, however, only requires that
<tt>char_traits&lt;charT&gt;::state_type</tt> meet the requirements of
CopyConstructible types.
</p>
<p>
<i>(2)</i>
Additionally, the <tt>stateT</tt> template argument has no
corresponding typedef in fpos which might make it difficult to use in
generic code.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Modify 21.1.2, p4 from
</p>
<p>
    Requires: <tt>state_type</tt> shall meet the requirements of
              CopyConstructible types (20.1.3).
</p>
<p>
    Requires: state_type shall meet the requirements of Assignable
              (23.1, p4), CopyConstructible (20.1.3), and
              DefaultConstructible  (20.1.4) types.
</p>

<p><b>Rationale:</b></p>
<p>The LWG feels this is two issues, as indicated above. The first is
a defect---std::basic_fstream is unimplementable without these
additional requirements---and the proposed resolution fixes it.  The
second is questionable; who would use that typedef?  The class
template fpos is used only in a very few places, all of which know the
state type already.  Unless motivation is provided, the second should
be considered NAD.</p>
<hr>
<a name="354"><h3>354.&nbsp;Associative container lower/upper bound requirements</h3></a><p><b>Section:</b>&nbsp;23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Hans Aberg&nbsp; <b>Date:</b>&nbsp;17 Dec 2001</p>
<p>
Discussions in the thread "Associative container lower/upper bound
requirements" on comp.std.c++ suggests that there is a defect in the
C++ standard, Table 69 of section 23.1.2, "Associative containers",
[lib.associative.reqmts].  It currently says:</p>

<blockquote>
<p>
a.find(k): returns an iterator pointing to an element with the key equivalent to
k, or a.end() if such an element is not found.
</p>

<p>
a.lower_bound(k): returns an iterator pointing to the first element with
key not less than k.
</p>

<p>
a.upper_bound(k): returns an iterator pointing to the first element with
key greater than k.
</p>
</blockquote>

<p>
We have "or a.end() if such an element is not found" for
<tt>find</tt>, but not for <tt>upper_bound</tt> or
<tt>lower_bound</tt>.  As the text stands, one would be forced to
insert a new element into the container and return an iterator to that
in case the sought iterator does not exist, which does not seem to be
the intention (and not possible with the "const" versions).
</p>
<p><b>Proposed resolution:</b></p>

<p>Change Table 69 of section 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> indicated entries
to:</p>

<blockquote>
<p>
a.lower_bound(k): returns an iterator pointing to the first element with
key not less than k, or a.end() if such an element is not found.
</p>

<p>
a.upper_bound(k): returns an iterator pointing to the first element with
key greater than k, or a.end() if such an element is not found.
</p>
</blockquote>

<p><i>[Curaçao: LWG reviewed PR.]</i></p>

<hr>
<a name="355"><h3>355.&nbsp;Operational semantics for a.back()</h3></a><p><b>Section:</b>&nbsp;23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Yaroslav Mironov&nbsp; <b>Date:</b>&nbsp;23 Jan 2002</p>

<p>Table 68 "Optional Sequence Operations" in 23.1.1/12
specifies operational semantics for "a.back()" as
"*--a.end()", which may be ill-formed <i>[because calling
operator-- on a temporary (the return) of a built-in type is
ill-formed]</i>, provided a.end() returns a simple pointer rvalue
(this is almost always the case for std::vector::end(), for
example). Thus, the specification is not only incorrect, it
demonstrates a dangerous construct: "--a.end()" may
successfully compile and run as intended, but after changing the type
of the container or the mode of compilation it may produce
compile-time error. </p>

<p><b>Proposed resolution:</b></p>
<p>Change the specification in table 68 "Optional Sequence
Operations" in 23.1.1/12 for "a.back()" from</p>


<blockquote>
*--a.end()
</blockquote>

<p>to</p>

<blockquote>
  { iterator tmp = a.end(); --tmp; return *tmp; }
</blockquote>

<p>and the specification for "a.pop_back()" from</p>

<blockquote>
a.erase(--a.end())
</blockquote>

<p>to</p>

<blockquote>
  { iterator tmp = a.end(); --tmp; a.erase(tmp); }
</blockquote>

<p><i>[Curaçao: LWG changed PR from "{ X::iterator tmp =
a.end(); return *--tmp; }" to "*a.rbegin()", and from
"{ X::iterator tmp = a.end(); a.erase(--tmp); }" to
"a.erase(rbegin())".]</i></p>

<p><i>[There is a second possible defect; table 68 "Optional
Sequence Operations" in the "Operational Semantics"
column uses operations present only in the "Reversible
Container" requirements, yet there is no stated dependency
between these separate requirements tables. Ask in Santa Cruz if the
LWG would like a new issue opened.]</i></p>

<p><i>[Santa Cruz: the proposed resolution is even worse than what's in
  the current standard: erase is undefined for reverse iterator.  If
  we're going to make the change, we need to define a temporary and
  use operator--.  Additionally, we don't know how prevalent this is:
  do we need to make this change in more than one place?  Martin has
  volunteered to review the standard and see if this problem occurs
  elsewhere.]</i></p>

<p><i>[Oxford: Matt provided new wording to address the concerns raised
  in Santa Cruz.  It does not appear that this problem appears
  anywhere else in clauses 23 or 24.]</i></p>

<p><i>[Kona: In definition of operational semantics of back(), change
"*tmp" to "return *tmp;"]</i></p>

<hr>
<a name="358"><h3>358.&nbsp;interpreting <tt>thousands_sep</tt> after a <tt>decimal_point</tt>
</h3></a><p><b>Section:</b>&nbsp;22.2.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.get.virtuals"> [lib.facet.num.get.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;12 Mar 2002</p>
<p>
I don't think <tt>thousands_sep</tt> is being treated correctly after
decimal_point has been seen. Since grouping applies only to the
integral part of the number, the first such occurrence should, IMO,
terminate Stage 2. (If it does not terminate it, then 22.2.2.1.2, p12
and 22.2.3.1.2, p3 need to explain how <tt>thousands_sep</tt> is to be
interpreted in the fractional part of a number.)
</p>

<p>
The easiest change I can think of that resolves this issue would be
something like below.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the first sentence of 22.2.2.1.2, p9 from
</p>

<blockquote>
    If discard is true then the position of the character is
    remembered, but the character is otherwise ignored. If it is not
    discarded, then a check is made to determine if c is allowed as
    the next character of an input field of the conversion specifier
    returned by stage 1. If so it is accumulated.
</blockquote>

<p>to</p>

<blockquote>
    If <tt>discard</tt> is true, then if <tt>'.'</tt> has not yet been
    accumulated, then the position of the character is remembered, but
    the character is otherwise ignored. Otherwise, if <tt>'.'</tt> has
    already been accumulated, the character is discarded and Stage 2
     terminates. ...
</blockquote>

<p><b>Rationale:</b></p>
<p>We believe this reflects the intent of the Standard.  Thousands sep
  characters after the decimal point are not useful in any locale.
  Some formatting conventions do group digits that follow the decimal
  point, but they usually introduce a different grouping character
  instead of reusing the thousand sep character.  If we want to add
  support for such conventions, we need to do so explicitly.</p>

<hr>
<a name="359"><h3>359.&nbsp;num_put&lt;&gt;::do_put (..., bool) undocumented</h3></a><p><b>Section:</b>&nbsp;22.2.2.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.members"> [lib.facet.num.put.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;12 Mar 2002</p>
<p>22.2.2.2.1, p1:</p>

    <pre>    iter_type put (iter_type out, ios_base&amp; str, char_type fill,
                   bool val) const;
    ...

    1   Returns: do_put (out, str, fill, val).
    </pre>

<p>AFAICS, the behavior of do_put (..., bool) is not documented anywhere,
however, 22.2.2.2.2, p23:</p>

<blockquote>
<pre>iter_type put (iter_type out, ios_base&amp; str, char_type fill,
               bool val) const;
</pre>


        Effects: If (str.flags() &amp; ios_base::boolalpha) == 0 then do
             out = do_put(out, str, fill, (int)val)
           Otherwise do
<pre>             string_type s =
                 val ? use_facet&lt;ctype&lt;charT&gt; &gt;(loc).truename()
                     : use_facet&lt;ctype&lt;charT&gt; &gt;(loc).falsename();
</pre>
           and then insert the characters of s into out. <i>out</i>.
</blockquote>

<p>
This means that the bool overload of <tt>do_put()</tt> will never be called,
which contradicts the first paragraph. Perhaps the declaration
should read <tt>do_put()</tt>, and not <tt>put()</tt>?
</p>

<p>
Note also that there is no <b>Returns</b> clause for this function, which
should probably be corrected, just as should the second occurrence
of <i>"out."</i> in the text.
</p>

<p>
I think the least invasive change to fix it would be something like
the following:
</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>, just above paragraph 1, remove
  the <tt>bool</tt> overload.</p>

<p>
In 22.2.2.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.facet.num.put.virtuals"> [lib.facet.num.put.virtuals]</a>, p23, make the following changes
</p>

<blockquote>
     Replace <tt>put()</tt> with <tt>do_put()</tt> in the declaration
     of the member function.
</blockquote>

<blockquote>
    Change the <b>Effects</b> clause to a <b>Returns</b> clause (to
    avoid the requirement to call <tt>do_put(..., int)</tt> from <tt>
    do_put (..., bool))</tt>
    like so:
</blockquote>

<blockquote>
    23   <b>Returns</b>: If <tt>(str.flags() &amp;
         ios_base::boolalpha) == 0</tt> then
         <tt>do_put (out, str, fill, (long)val)</tt>
         Otherwise the function obtains a string <tt>s</tt> as if by
<pre>             string_type s =
                val ? use_facet&lt;ctype&lt;charT&gt; &gt;(loc).truename()
                    : use_facet&lt;ctype&lt;charT&gt; &gt;(loc).falsename();
</pre>
         and then inserts each character <tt>c</tt> of s into out via
           <tt>*out++ = c</tt>
         and returns <tt>out</tt>.
</blockquote>

<p><b>Rationale:</b></p>
<p>
This fixes a couple of obvious typos, and also fixes what appears to
be a requirement of gratuitous inefficiency.
</p>
<hr>
<a name="360"><h3>360.&nbsp;locale mandates inefficient implementation</h3></a><p><b>Section:</b>&nbsp;22.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale"> [lib.locale]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;12 Mar 2002</p>
<p>
22.1.1, p7 (copied below) allows iostream formatters and extractors
to make assumptions about the values returned from facet members.
However, such assumptions are apparently not guaranteed to hold
in other cases (e.g., when the facet members are being called directly
rather than as a result of iostream calls, or between successive
calls to the same iostream functions with no interevening calls to
<tt>imbue()</tt>, or even when the facet member functions are called
from other member functions of other facets). This restriction
prevents locale from being implemented efficiently.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the first sentence in 22.1.1, p7 from</p>
<blockquote>
    In successive calls to a locale facet member function during
    a call to an iostream inserter or extractor or a streambuf member
    function, the returned result shall be identical. [Note: This
    implies that such results may safely be reused without calling
    the locale facet member function again, and that member functions
    of iostream classes cannot safely call <tt>imbue()</tt>
    themselves, except as specified elsewhere. --end note]
</blockquote>

<p>to</p>

<blockquote>
    In successive calls to a locale facet member function on a facet
    object installed in the same locale, the returned result shall be
    identical. ...
</blockquote>

<p><b>Rationale:</b></p>
<p>This change is reasonable becuase it clarifies the intent of this
  part of the standard.</p>
<hr>
<a name="362"><h3>362.&nbsp;bind1st/bind2nd type safety</h3></a><p><b>Section:</b>&nbsp;D.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/future.html#depr.lib.binders"> [depr.lib.binders]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Andrew Demkin&nbsp; <b>Date:</b>&nbsp;26 Apr 2002</p>
<p>
The definition of bind1st() (<font color="red">20.5.6.2</font>) can result in
the construction of an unsafe binding between incompatible pointer
types. For example, given a function whose first parameter type is
'pointer to T', it's possible without error to bind an argument of
type 'pointer to U' when U does not derive from T:
</p>
<pre>   foo(T*, int);

   struct T {};
   struct U {};

   U u;

   int* p;
   int* q;

   for_each(p, q, bind1st(ptr_fun(foo), &amp;u));    // unsafe binding
</pre>

<p>
The definition of bind1st() includes a functional-style conversion to
map its argument to the expected argument type of the bound function
(see below):
</p>
<pre>  typename Operation::first_argument_type(x)
</pre>

<p>
A functional-style conversion (5.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/expr.html#expr.type.conv"> [expr.type.conv]</a>) is defined to be
semantically equivalent to an explicit cast expression (5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/expr.html#expr.cast"> [expr.cast]</a>), which may (according to 5.4, paragraph 5) be interpreted
as a reinterpret_cast, thus masking the error.
</p>

<p>The problem and proposed change also apply to <font color="red">20.5.6.4</font>.</p>
<p><b>Proposed resolution:</b></p>
<p>Add this sentence to the end of 20.5.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.arithmetic.operations"> [lib.arithmetic.operations]</a>/1:
  "Binders <tt>bind1st</tt> and <tt>bind2nd</tt> are deprecated in
  favor of <tt>std::tr1::bind</tt>."</p>

<p>(Notes to editor: (1) when and if tr1::bind is incorporated into
  the standard, "std::tr1::bind" should be changed to "std::bind". (2)
  20.5.6 should probably be moved to Annex D.</p>
<p><b>Rationale:</b></p>
<p>There is no point in fixing bind1st and bind2nd.  tr1::bind is a
  superior solution.  It solves this problem and others.</p>
<hr>
<a name="363"><h3>363.&nbsp;Missing exception specification in 27.4.2.1.1</h3></a><p><b>Section:</b>&nbsp;27.4.2.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios::failure"> [lib.ios::failure]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown and Marc Paterno&nbsp; <b>Date:</b>&nbsp;20 May 2002</p>
<p>
The destructor of ios_base::failure should have an empty throw
specification, because the destructor of its base class, exception, is
declared in this way.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the destructor to</p>
<pre>  virtual ~failure() throw();
</pre>
<p><b>Rationale:</b></p>
<p>Fixes an obvious glitch.  This is almost editorial.</p>
<hr>
<a name="364"><h3>364.&nbsp;Inconsistent wording in 27.5.2.4.2</h3></a><p><b>Section:</b>&nbsp;27.5.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.buffer"> [lib.streambuf.virt.buffer]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown, Marc Paterno&nbsp; <b>Date:</b>&nbsp;10 May 2002</p>
<p>
27.5.2.4.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.streambuf.virt.buffer"> [lib.streambuf.virt.buffer]</a> paragraph 1 is inconsistent with the Effects
clause for seekoff.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Make this paragraph, the Effects clause for setbuf, consistent in wording
with the Effects clause for seekoff in paragraph 3 by amending paragraph 1
to indicate the purpose of setbuf:
</p>

<p>Original text:</p>

<blockquote>
1 Effects: Performs an operation that is defined separately for each
class derived from basic_streambuf in this clause (27.7.1.3, 27.8.1.4).
</blockquote>

<p>Proposed text:</p>

<blockquote>
1 Effects: Influences stream buffering in a way that is defined separately
for each class derived from basic_streambuf in this clause
(27.7.1.3, 27.8.1.4).
</blockquote>

<p><b>Rationale:</b></p>
<p>The LWG doesn't believe there is any normative difference between
  the existing wording and what's in the proposed resolution, but the
  change may make the intent clearer.</p>
<hr>
<a name="365"><h3>365.&nbsp;Lack of const-qualification in clause 27</h3></a><p><b>Section:</b>&nbsp;27 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.input.output"> [lib.input.output]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown, Marc Paterno&nbsp; <b>Date:</b>&nbsp;10 May 2002</p>
<p>
Some stream and streambuf member functions are declared non-const,
even thought they appear only to report information rather than to
change an object's logical state.  They should be declared const.  See
document N1360 for details and rationale.
</p>

<p>The list of member functions under discussion: <tt>in_avail</tt>,
<tt>showmanyc</tt>, <tt>tellg</tt>, <tt>tellp</tt>, <tt>is_open</tt>.</p>

<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#73">73</a></p>

<p><b>Proposed resolution:</b></p>
<p>In 27.8.1.5, 27.8.1.7, 27.8.1.8, 27.8.1.10, 27.8.1.11, and 27.8.1.13</p>
<p>Replace</p>
<pre>  bool is_open();
</pre>
<p>with</p>
<pre>  bool is_open() const;
</pre>
<p><b>Rationale:</b></p>
<p>Of the changes proposed in N1360, the only one that is safe is
changing the filestreams' is_open to const.  The LWG believed that
this was NAD the first time it considered this issue (issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#73">73</a>), but now thinks otherwise.  The corresponding streambuf
member function, after all,is already const.</p>

<p>The other proposed changes are less safe, because some streambuf
functions that appear merely to report a value do actually perform
mutating operations.  It's not even clear that they should be
considered "logically const", because streambuf has two interfaces, a
public one and a protected one.  These functions may, and often do,
change the state as exposed by the protected interface, even if the
state exposed by the public interface is unchanged.</p>

<p>Note that implementers can make this change in a binary compatible
way by providing both overloads; this would be a conforming extension.</p>

<hr>
<a name="369"><h3>369.&nbsp;io stream objects and static ctors</h3></a><p><b>Section:</b>&nbsp;27.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostream.objects"> [lib.iostream.objects]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Ruslan Abdikeev&nbsp; <b>Date:</b>&nbsp;8 Jul 2002</p>
<p>
Is it safe to use standard iostream objects from constructors of
static objects?  Are standard iostream objects constructed and are
their associations established at that time?
</p>

<p>Surpisingly enough, Standard does NOT require that.</p>

<p>
27.3/2 [lib.iostream.objects] guarantees that standard iostream
objects are constructed and their associations are established before
the body of main() begins execution.  It also refers to ios_base::Init
class as the panacea for constructors of static objects.
</p>

<p>
However, there's nothing in 27.3 [lib.iostream.objects],
in 27.4.2 [lib.ios.base], and in 27.4.2.1.6 [lib.ios::Init],
that would require implementations to allow access to standard
iostream objects from constructors of static objects.
</p>

<p>Details:</p>

<p>Core text refers to some magic object ios_base::Init, which will
be discussed below:</p>

<blockquote>
    "The [standard iostream] objects are constructed, and their
    associations are established at some time prior to or during
    first time an object of class basic_ios&lt;charT,traits&gt;::Init
    is constructed, and in any case before the body of main
    begins execution." (27.3/2 [lib.iostream.objects])
</blockquote>

<p>
The first <i>non-normative</i> footnote encourages implementations
to initialize standard iostream objects earlier than required.
</p>

<p>However, the second <i>non-normative</i> footnote makes an explicit
and unsupported claim:</p>

<blockquote>
  "Constructors and destructors for static objects can access these
  [standard iostream] objects to read input from stdin or write output
  to stdout or stderr." (27.3/2 footnote 265 [lib.iostream.objects])
</blockquote>

<p>
The only bit of magic is related to that ios_base::Init class.  AFAIK,
the rationale behind ios_base::Init was to bring an instance of this
class to each translation unit which #included &lt;iostream&gt; or
related header.  Such an inclusion would support the claim of footnote
quoted above, because in order to use some standard iostream object it
is necessary to #include &lt;iostream&gt;.
</p>

<p>
However, while Standard explicitly describes ios_base::Init as
an appropriate class for doing the trick, I failed to found a
mention of an _instance_ of ios_base::Init in Standard.
</p>
<p><b>Proposed resolution:</b></p>

<p>Add to 27.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostream.objects"> [lib.iostream.objects]</a>, p2, immediately before the last sentence
of the paragraph, the following two sentences:</p>

<blockquote>
If a translation unit includes &lt;iostream&gt;, or explicitly
constructs an ios_base::Init object, these stream objects shall
be constructed before dynamic initialization of non-local
objects defined later in that translation unit, and these stream
objects shall be destroyed after the destruction of dynamically
initialized non-local objects defined later in that translation unit.
</blockquote>

<p><i>[Lillehammer: Matt provided wording.]</i></p>
<p><i>[Mont Tremblant: Matt provided revised wording.]</i></p>
<p><b>Rationale:</b></p>
<p>
The original proposed resolution unconditionally required
implementations to define an ios_base::Init object of some
implementation-defined name in the header &lt;iostream&gt;. That's an
overspecification. First, defining the object may be unnecessary
and even detrimental to performance if an implementation can
guarantee that the 8 standard iostream objects will be initialized
before any other user-defined object in a program. Second, there
is no need to require implementations to document the name of the
object.</p>

<p>
The new proposed resolution gives users guidance on what they need to
do to ensure that stream objects are constructed during startup.</p>
<hr>
<a name="370"><h3>370.&nbsp;Minor error in basic_istream::get</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Ray Lischner&nbsp; <b>Date:</b>&nbsp;15 Jul 2002</p>
<p>Defect report for description of basic_istream::get (section 27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>), paragraph 15. The description for the get function
with the following signature:</p>

<pre>  basic_istream&lt;charT,traits&gt;&amp; get(basic_streambuf&lt;char_type,traits&gt;&amp;
  sb);
</pre>

<p>is incorrect. It reads</p>

<blockquote>
  Effects: Calls get(s,n,widen('\n'))
</blockquote>

<p>which I believe should be:</p>

<blockquote>
  Effects: Calls get(sb,widen('\n'))
</blockquote>
<p><b>Proposed resolution:</b></p>
<p>Change the <b>Effects</b> paragraph to:</p>
<blockquote>
  Effects: Calls get(sb,this-&gt;widen('\n'))
</blockquote>

<p><i>[Pre-Oxford: Minor correction from Howard: replaced 'widen' 
      with 'this-&gt;widen'.]</i></p>

<p><b>Rationale:</b></p>
<p>Fixes an obvious typo.</p>
<hr>
<a name="371"><h3>371.&nbsp;Stability of multiset and multimap member functions</h3></a><p><b>Section:</b>&nbsp;23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Frank Compagner&nbsp; <b>Date:</b>&nbsp;20 Jul 2002</p>
<p>
The requirements for multiset and multimap containers (23.1
[lib.containers.requirements], 23.1.2 [lib.associative.reqmnts],
23.3.2 [lib.multimap] and 23.3.4 [lib.multiset]) make no mention of
the stability of the required (mutating) member functions. It appears
the standard allows these functions to reorder equivalent elements of
the container at will, yet the pervasive red-black tree implementation
appears to provide stable behaviour.
</p>

<p>This is of most concern when considering the behaviour of erase().
A stability requirement would guarantee the correct working of the
following 'idiom' that removes elements based on a certain predicate
function.
</p>

<pre>  multimap&lt;int, int&gt; m;
  multimap&lt;int, int&gt;::iterator i = m.begin();
  while (i != m.end()) {
      if (pred(i))
          m.erase (i++);
      else
          ++i;
  }
</pre>

<p>
Although clause 23.1.2/8 guarantees that i remains a valid iterator
througout this loop, absence of the stability requirement could
potentially result in elements being skipped. This would make
this code incorrect, and, furthermore, means that there is no way
of erasing these elements without iterating first over the entire
container, and second over the elements to be erased. This would
be unfortunate, and have a negative impact on both performance and
code simplicity.
</p>

<p>
If the stability requirement is intended, it should be made explicit
(probably through an extra paragraph in clause 23.1.2).
</p>
<p>
If it turns out stability cannot be guaranteed, i'd argue that a
remark or footnote is called for (also somewhere in clause 23.1.2) to
warn against relying on stable behaviour (as demonstrated by the code
above).  If most implementations will display stable behaviour, any
problems emerging on an implementation without stable behaviour will
be hard to track down by users. This would also make the need for an
erase_if() member function that much greater.
</p>

<p>This issue is somewhat related to LWG issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#130">130</a>.</p>

<p><b>Proposed resolution:</b></p>

<p>Add the following to the end of 23.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.associative.reqmts"> [lib.associative.reqmts]</a> paragraph 4: 
"For <tt>multiset</tt> and <tt>multimap</tt>, <tt>insert</tt>and <tt>erase</tt>
  are <i>stable</i>: they preserve the relative ordering of equivalent
  elements.</p> 

<p><i>[Lillehammer: Matt provided wording]</i></p>
<p><i>[Joe Gottman points out that the provided wording does not address
multimap and multiset.  N1780 also addresses this issue and suggests
wording.]</i></p>

<p><i>[Mont Tremblant: Changed set and map to multiset and multimap.]</i></p>

<p><b>Rationale:</b></p>
<p>The LWG agrees that this guarantee is necessary for common user
  idioms to work, and that all existing implementations provide this
  property.  Note that this resolution guarantees stability for
  multimap and multiset, not for all associative containers in
  general.</p>

<hr>
<a name="373"><h3>373.&nbsp;Are basic_istream and basic_ostream to use (exceptions()&amp;badbit) != 0 ?</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.reqmts"> [lib.istream.formatted.reqmts]</a>, 27.6.2.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.formatted.reqmts"> [lib.ostream.formatted.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Keith Baker&nbsp; <b>Date:</b>&nbsp;23 Jul 2002</p>

<p>
In 27.6.1.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.reqmts"> [lib.istream.formatted.reqmts]</a> and 27.6.2.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.formatted.reqmts"> [lib.ostream.formatted.reqmts]</a>
(exception()&amp;badbit) != 0 is used in testing for rethrow, yet
exception() is the constructor to class std::exception in 18.6.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.type.info"> [lib.type.info]</a> that has no return type. Should member function
exceptions() found in 27.4.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ios"> [lib.ios]</a> be used instead?
</p>

<p><b>Proposed resolution:</b></p>
<p>
In 27.6.1.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.formatted.reqmts"> [lib.istream.formatted.reqmts]</a> and 27.6.2.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.formatted.reqmts"> [lib.ostream.formatted.reqmts]</a>, change
"(exception()&amp;badbit) != 0" to "(exceptions()&amp;badbit) != 0".
</p>
<p><b>Rationale:</b></p>
<p>Fixes an obvious typo.</p>
<hr>
<a name="375"><h3>375.&nbsp;basic_ios should be ios_base in 27.7.1.3</h3></a><p><b>Section:</b>&nbsp;27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Ray Lischner&nbsp; <b>Date:</b>&nbsp;14 Aug 2002</p>
<p>
In Section 27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>: Table 90, Table 91, and paragraph
14 all contain references to "basic_ios::" which should be
"ios_base::".
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change all references to "basic_ios" in Table 90, Table 91, and
paragraph 14 to "ios_base".
</p>
<p><b>Rationale:</b></p>
<p>Fixes an obvious typo.</p>
<hr>
<a name="376"><h3>376.&nbsp;basic_streambuf semantics</h3></a><p><b>Section:</b>&nbsp;27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Ray Lischner&nbsp; <b>Date:</b>&nbsp;14 Aug 2002</p>
<p>
In Section 27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>, Table 90, the implication is that
the four conditions should be mutually exclusive, but they are not.
The first two cases, as written, are subcases of the third.</p>

<p>
As written, it is unclear what should be the result if cases 1 and 2
are both true, but case 3 is false.
</p>

<p><b>Proposed resolution:</b></p>

<p>Rewrite these conditions as:</p>
<blockquote>
<p>
  (which &amp; (ios_base::in|ios_base::out)) == ios_base::in
</p>

<p>
  (which &amp; (ios_base::in|ios_base::out)) == ios_base::out
</p>

<p>
  (which &amp; (ios_base::in|ios_base::out)) == 
(ios_base::in|ios_base::out)
   and way == either ios_base::beg or ios_base::end
</p>

<p>Otherwise</p>
</blockquote>

<p><b>Rationale:</b></p>
<p>It's clear what we wanted to say, we just failed to say it.  This
  fixes it.</p>
<hr>
<a name="379"><h3>379.&nbsp;nonsensical ctype::do_widen() requirement</h3></a><p><b>Section:</b>&nbsp;22.2.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;6 Sep 2002</p>
<p>
The last sentence in 22.2.1.1.2, p11 below doesn't seem to make sense.
</p>
<pre>  charT do_widen (char c) const;

  -11- Effects: Applies the simplest reasonable transformation from
       a char value or sequence of char values to the corresponding
       charT value or values. The only characters for which unique
       transformations are required are those in the basic source
       character set (2.2). For any named ctype category with a
       ctype&lt;charT&gt; facet ctw and valid ctype_base::mask value
       M (is(M, c) || !ctw.is(M, do_widen(c))) is true.
</pre>
<p>
Shouldn't the last sentence instead read
</p>
<pre>       For any named ctype category with a ctype&lt;char&gt; facet ctc
       and valid ctype_base::mask value M
       (ctc.is(M, c) || !is(M, do_widen(c))) is true.
</pre>
<p>
I.e., if the narrow character c is not a member of a class of
characters then neither is the widened form of c. (To paraphrase
footnote 224.)
</p>
<p><b>Proposed resolution:</b></p>
<p>
Replace the last sentence of 22.2.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.ctype.virtuals"> [lib.locale.ctype.virtuals]</a>, p11 with the
following text:
</p>
<pre>       For any named ctype category with a ctype&lt;char&gt; facet ctc
       and valid ctype_base::mask value M,
       (ctc.is(M, c) || !is(M, do_widen(c))) is true.
</pre>

<p><i>[Kona: Minor edit. Added a comma after the <i>M</i> for clarity.]</i></p>

<p><b>Rationale:</b></p>
<p>The LWG believes this is just a typo, and that this is the correct fix.</p>
<hr>
<a name="380"><h3>380.&nbsp;typos in codecvt tables 53 and 54</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;6 Sep 2002</p>
<p>
Tables 53 and 54 in 22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a> are both titled "convert
result values," when surely "do_in/do_out result values" must have
been intended for Table 53 and "do_unshift result values" for Table
54.
</p>
<p>
Table 54, row 3 says that the meaning of partial is "more characters
needed to be supplied to complete termination." The function is not
supplied any characters, it is given a buffer which it fills with
characters or, more precisely, destination elements (i.e., an escape
sequence). So partial means that space for more than (to_limit - to)
destination elements was needed to terminate a sequence given the
value of state.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the title of Table 53 to "do_in/do_out result values" and
the title of Table 54 to "do_unshift result values."
</p>
<p>
Change the text in Table 54, row 3 (the <b>partial</b> row), under the
heading Meaning, to "space for more than (to_limit - to) destination
elements was needed to terminate a sequence given the value of state."
</p>
<hr>
<a name="381"><h3>381.&nbsp;detection of invalid mbstate_t in codecvt</h3></a><p><b>Section:</b>&nbsp;22.2.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.codecvt.byname"> [lib.locale.codecvt.byname]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;6 Sep 2002</p>
<p>
All but one codecvt member functions that take a state_type argument
list as one of their preconditions that the state_type argument have
a valid value. However, according to 22.2.1.5.2, p6,
codecvt::do_unshift() is the only codecvt member that is supposed to
return error if the state_type object is invalid.
</p>

<p>
It seems to me that the treatment of state_type by all codecvt member
functions should be the same and the current requirements should be
changed. Since the detection of invalid state_type values may be
difficult in general or computationally expensive in some specific
cases, I propose the following:
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add a new paragraph before 22.2.1.5.2, p5, and after the function
declaration below
</p>
<pre>    result do_unshift(stateT&amp; state,
    externT* to, externT* to_limit, externT*&amp; to_next) const;
</pre>
<p>
as follows:
</p>
<pre>    Requires: (to &lt;= to_end) well defined and true; state initialized,
    if at the beginning of a sequence, or else equal to the result of
    converting the preceding characters in the sequence.
</pre>
<p>
and change the text in Table 54, row 4, the <b>error</b> row, under
the heading Meaning, from
</p>
<pre>    state has invalid value
</pre>
<p>
to
</p>
<pre>    an unspecified error has occurred
</pre>
<p><b>Rationale:</b></p>
<p>The intent is that implementations should not be required to detect
invalid state values; such a requirement appears nowhere else.  An
invalid state value is a precondition violation, <i>i.e.</i> undefined
behavior.  Implementations that do choose to detect invalid state
values, or that choose to detect any other kind of error, may return
<b>error</b> as an indication.</p>
<hr>
<a name="383"><h3>383.&nbsp;Bidirectional iterator assertion typo</h3></a><p><b>Section:</b>&nbsp;24.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.bidirectional.iterators"> [lib.bidirectional.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;ysapir (submitted via comp.std.c++)&nbsp; <b>Date:</b>&nbsp;17 Oct 2002</p>
<p>
Following a discussion on the boost list regarding end iterators and
the possibility of performing operator--() on them, it seems to me
that there is a typo in the standard.  This typo has nothing to do
with that discussion.
</p>

<p>
I have checked this newsgroup, as well as attempted a search of the
Active/Defect/Closed Issues List on the site for the words "s is
derefer" so I believe this has not been proposed before.  Furthermore,
the "Lists by Index" mentions only DR <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#299">299</a> on section
24.1.4, and DR <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#299">299</a> is not related to this issue.
</p>

<p>
The standard makes the following assertion on bidirectional iterators,
in section 24.1.4 [lib.bidirectional.iterators], Table 75:
</p>

<pre>                         operational  assertion/note
expression  return type   semantics    pre/post-condition

--r          X&amp;                        pre: there exists s such
                                       that r == ++s.
                                       post: s is dereferenceable.
                                       --(++r) == r.
                                       --r == --s implies r == s.
                                       &amp;r == &amp;--r.
</pre>

<p>
(See <a href="http://aspn.activestate.com/ASPN/Mail/Message/boost/1395763">http://aspn.activestate.com/ASPN/Mail/Message/boost/1395763</a>.)
</p>

<p>
In particular, "s is dereferenceable" seems to be in error.  It seems
that the intention was to say "r is dereferenceable".
</p>

<p>
If it were to say "r is dereferenceable" it would
make perfect sense.  Since s must be dereferenceable prior to
operator++, then the natural result of operator-- (to undo operator++)
would be to make r dereferenceable.  Furthermore, without other
assertions, and basing only on precondition and postconditions, we
could not otherwise know this.  So it is also interesting information.
</p>

<p><b>Proposed resolution:</b></p>
<p>
Change the guarantee to "postcondition: r is dereferenceable."
</p>
<p><b>Rationale:</b></p>
<p>Fixes an obvious typo</p>
<hr>
<a name="384"><h3>384.&nbsp;equal_range has unimplementable runtime complexity</h3></a><p><b>Section:</b>&nbsp;25.3.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.equal.range"> [lib.equal.range]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Hans Bos&nbsp; <b>Date:</b>&nbsp;18 Oct 2002</p>
<p>
Section 25.3.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.equal.range"> [lib.equal.range]</a>
states that at most 2 * log(last - first) + 1
comparisons are allowed for equal_range.
</p>

<p>It is not possible to implement equal_range with these constraints.</p>

<p>In a range of one element as in:</p>
<pre>    int x = 1;
    equal_range(&amp;x, &amp;x + 1, 1)
</pre>

<p>it is easy to see that at least 2 comparison operations are needed.</p>

<p>For this case at most 2 * log(1) + 1 = 1 comparison is allowed.</p>

<p>I have checked a few libraries and they all use the same (nonconforming)
algorithm for equal_range that has a complexity of</p>
<pre>     2* log(distance(first, last)) + 2.
</pre>
<p>I guess this is the algorithm that the standard assumes for equal_range.</p>

<p>
It is easy to see that 2 * log(distance) + 2 comparisons are enough
since equal range can be implemented with lower_bound and upper_bound
(both log(distance) + 1).
</p>

<p>
I think it is better to require something like 2log(distance) + O(1)  (or
even logarithmic as multiset::equal_range).
Then an implementation has more room to optimize for certain cases (e.g.
have log(distance) characteristics when at most match is found in the range
but 2log(distance) + 4 for the worst case).
</p>

<p><b>Proposed resolution:</b></p>
<p>In 25.3.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.lower.bound"> [lib.lower.bound]</a>/4, change <tt>log(last - first) + 1</tt>
to <tt>log<sub>2</sub>(last - first) + <i>O</i>(1)</tt>.</p>

<p>In 25.3.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.upper.bound"> [lib.upper.bound]</a>/4, change <tt>log(last - first) + 1</tt>
to <tt>log<sub>2</sub>(last - first) + <i>O</i>(1)</tt>.</p>

<p>In 25.3.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.equal.range"> [lib.equal.range]</a>/4, change <tt>2*log(last - first) + 1</tt>
to <tt>2*log<sub>2</sub>(last - first) + <i>O</i>(1)</tt>.</p>

<p><i>[Matt provided wording]</i></p>
<p><b>Rationale:</b></p>
<p>The LWG considered just saying <i>O</i>(log n) for all three, but
Ê decided that threw away too much valuable information.Ê The fact
Ê that lower_bound is twice as fast as equal_range is important.
Ê However, it's better to allow an arbitrary additive constant than to
Ê specify an exact count.Ê An exact count would have to
Ê involve <tt>floor</tt> or <tt>ceil</tt>.Ê It would be too easy to
Ê get this wrong, and don't provide any substantial value for users.</p>
<hr>
<a name="386"><h3>386.&nbsp;Reverse iterator's operator[] has impossible return type</h3></a><p><b>Section:</b>&nbsp;24.4.1.3.11 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.op-="> [lib.reverse.iter.op-=]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;23 Oct 2002</p>
<p>In 24.4.1.3.11 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.op-="> [lib.reverse.iter.op-=]</a>, <tt>reverse_iterator&lt;&gt;::operator[]</tt> 
is specified as having a return type of <tt>reverse_iterator::reference</tt>,
which is the same as <tt>iterator_traits&lt;Iterator&gt;::reference</tt>.
(Where <tt>Iterator</tt> is the underlying iterator type.)</p>

<p>The trouble is that <tt>Iterator</tt>'s own operator[] doesn't
  necessarily have a return type
  of <tt>iterator_traits&lt;Iterator&gt;::reference</tt>.   Its
  return type is merely required to be convertible
  to <tt>Iterator</tt>'s value type.  The return type specified for
  reverse_iterator's operator[] would thus appear to be impossible.</p>

<p>With the resolution of issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#299">299</a>, the type of
  <tt>a[n]</tt> will continue to be required (for random access
  iterators) to be convertible to the value type, and also <tt>a[n] =
  t</tt> will be a valid expression.  Implementations of
  <tt>reverse_iterator</tt> will likely need to return a proxy from
  <tt>operator[]</tt> to meet these requirements. As mentioned in the
  comment from Dave Abrahams, the simplest way to specify that
  <tt>reverse_iterator</tt> meet this requirement to just mandate
  it and leave the return type of <tt>operator[]</tt> unspecified.</p>

<p><b>Proposed resolution:</b></p>

<p>In 24.4.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.reverse.iter.requirements"> [lib.reverse.iter.requirements]</a> change:</p>

<blockquote>
<pre>reference operator[](difference_type n) const;
</pre>
</blockquote>

<p>to:</p>

<blockquote>
<pre><b><i>unspecified</i></b> operator[](difference_type n) const; // see <font color="red">lib.random.access.iterators</font>
</pre>
</blockquote>




<p><i>[
Comments from Dave Abrahams: IMO we should resolve 386 by just saying
    that the return type of reverse_iterator's operator[] is
    unspecified, allowing the random access iterator requirements to
    impose an appropriate return type.  If we accept 299's proposed
    resolution (and I think we should), the return type will be
    readable and writable, which is about as good as we can do.
]</i></p>
<hr>
<a name="389"><h3>389.&nbsp;Const overload of valarray::operator[] returns by value</h3></a><p><b>Section:</b>&nbsp;26.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex"> [lib.complex]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Gabriel Dos Reis&nbsp; <b>Date:</b>&nbsp;8 Nov 2002</p>
<p>Consider the following program:</p>
<pre>    #include &lt;iostream&gt;
    #include &lt;ostream&gt;
    #include &lt;vector&gt;
    #include &lt;valarray&gt;
    #include &lt;algorithm&gt;
    #include &lt;iterator&gt;
    template&lt;typename Array&gt;
    void print(const Array&amp; a)
    {
    using namespace std;
    typedef typename Array::value_type T;
    copy(&amp;a[0], &amp;a[0] + a.size(),
    ostream_iterator&lt;T&gt;(std::cout, " "));
    }
    template&lt;typename T, unsigned N&gt;
    unsigned size(T(&amp;)[N]) { return N; }
    int main()
    {
    double array[] = { 0.89, 9.3, 7, 6.23 };
    std::vector&lt;double&gt; v(array, array + size(array));
    std::valarray&lt;double&gt; w(array, size(array));
    print(v); // #1
    std::cout &lt;&lt; std::endl;
    print(w); // #2
    std::cout &lt;&lt; std::endl;
    }
</pre>

<p>While the call numbered #1 succeeds, the call numbered #2 fails
because the const version of the member function
valarray&lt;T&gt;::operator[](size_t) returns a value instead of a
const-reference. That seems to be so for no apparent reason, no
benefit. Not only does that defeats users' expectation but it also
does hinder existing software (written either in C or Fortran)
integration within programs written in C++.  There is no reason why
subscripting an expression of type valarray&lt;T&gt; that is const-qualified
should not return a const T&amp;.</p>
<p><b>Proposed resolution:</b></p>
<p>In the class synopsis in 26.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.complex"> [lib.complex]</a>, and in
<font color="red">26.3.2.3</font> just above paragraph 1, change</p>
<pre>  T operator[](size_t const);
</pre>
<p>to</p>
<pre>  const T&amp; operator[](size_t const);
</pre>

<p><i>[Kona: fixed a minor typo: put semicolon at the end of the line
  wehre it belongs.]</i></p>

<p><b>Rationale:</b></p>
<p>Return by value seems to serve no purpose.  Valaray was explicitly
designed to have a specified layout so that it could easily be
integrated with libraries in other languages, and return by value
defeats that purpose.  It is believed that this change will have no
impact on allowable optimizations.</p>
<hr>
<a name="391"><h3>391.&nbsp;non-member functions specified as const</h3></a><p><b>Section:</b>&nbsp;22.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.conversions"> [lib.conversions]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;James Kanze&nbsp; <b>Date:</b>&nbsp;10 Dec 2002</p>
<p>
The specifications of toupper and tolower both specify the functions as
const, althought they are not member functions, and are not specified as
const in the header file synopsis in section 22.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locales"> [lib.locales]</a>.
</p>
<p><b>Proposed resolution:</b></p>
<p>In 22.1.3.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.conversions"> [lib.conversions]</a>, remove <tt>const</tt> from the function
  declarations of std::toupper and std::tolower</p>
<p><b>Rationale:</b></p>
<p>Fixes an obvious typo</p>
<hr>
<a name="395"><h3>395.&nbsp;inconsistencies in the definitions of rand() and random_shuffle()</h3></a><p><b>Section:</b>&nbsp;26.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.numarray"> [lib.numarray]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;James Kanze&nbsp; <b>Date:</b>&nbsp;3 Jan 2003</p>
<p>
In 26.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-numerics.html#lib.numarray"> [lib.numarray]</a>, the C++ standard refers to the C standard for the
definition of rand(); in the C standard, it is written that "The
implementation shall behave as if no library function calls the rand
function."
</p>

<p>
In 25.2.11 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.random.shuffle"> [lib.alg.random.shuffle]</a>, there is no specification as to
how the two parameter version of the function generates its random
value.  I believe that all current implementations in fact call rand()
(in contradiction with the requirement avove); if an implementation does
not call rand(), there is the question of how whatever random generator
it does use is seeded.  Something is missing.
</p>

<p><b>Proposed resolution:</b></p>
<p>
In [lib.c.math], add a paragraph specifying that the C definition of
rand shal be modified to say that "Unless otherwise specified, the
implementation shall behave as if no library function calls the rand
function."
</p>

<p>
In [lib.alg.random.shuffle], add a sentence to the effect that "In
the two argument form of the function, the underlying source of
random numbers is implementation defined. [Note: in particular, an
implementation is permitted to use <tt>rand</tt>.]
</p>
<p><b>Rationale:</b></p>
<p>The original proposed resolution proposed requiring the
  two-argument from of <tt>random_shuffle</tt> to
  use <tt>rand</tt>. We don't want to do that, because some existing
  implementations already use something else: gcc
  uses <tt>lrand48</tt>, for example.  Using <tt>rand</tt> presents a
  problem if the number of elements in the sequence is greater than
  RAND_MAX.</p> 
<hr>
<a name="400"><h3>400.&nbsp;redundant type cast in lib.allocator.members</h3></a><p><b>Section:</b>&nbsp;20.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.allocator.members"> [lib.allocator.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Markus Mauhart&nbsp; <b>Date:</b>&nbsp;27 Feb 2003</p>
<p>
20.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.allocator.members"> [lib.allocator.members]</a> allocator members, contains
the following 3 lines:
</p>

<pre>  12 Returns: new((void *) p) T( val)
     void destroy(pointer p);
  13 Returns: ((T*) p)-&gt;~T()
</pre>

<p>
The type cast "(T*) p" in the last line is redundant cause
we know that std::allocator&lt;T&gt;::pointer is a typedef for T*.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Replace "((T*) p)" with "p".
</p>
<p><b>Rationale:</b></p>
<p>Just a typo, this is really editorial.</p>
<hr>
<a name="402"><h3>402.&nbsp;wrong new expression in [some_]allocator::construct</h3></a><p><b>Section:</b>&nbsp;20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>, 20.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.allocator.members"> [lib.allocator.members]</a>, &nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Markus Mauhart&nbsp; <b>Date:</b>&nbsp;27 Feb 2003</p>
<p>
This applies to the new expression that is contained in both par12 of
20.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.allocator.members"> [lib.allocator.members]</a> and in par2 (table 32) of 20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a>.
I think this new expression is wrong, involving unintended side
effects.
</p>


<p>20.6.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.allocator.members"> [lib.allocator.members]</a>  contains the following 3 lines:</p>

<pre>  11 Returns: the largest value N for which the call allocate(N,0) might succeed.
     void construct(pointer p, const_reference val);
  12 Returns: new((void *) p) T( val)
</pre>


<p>20.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.default.con.req"> [lib.default.con.req]</a> in table 32 has the following line:</p>
<pre>  a.construct(p,t)   Effect: new((void*)p) T(t)
</pre>

<p>
.... with the prerequisits coming from the preceding two paragraphs,
especially from table 31:
</p>

<pre>  alloc&lt;T&gt;             a     ;// an allocator for T
  alloc&lt;T&gt;::pointer    p     ;// random access iterator
                              // (may be different from T*)
  alloc&lt;T&gt;::reference  r = *p;// T&amp;
  T const&amp;             t     ;
</pre>

<p>
Cause of using "new" but not "::new", any existing "T::operator new"
function will hide the global placement new function. When there is no
"T::operator new" with adequate signature,
every_alloc&lt;T&gt;::construct(..) is ill-formed, and most
std::container&lt;T,every_alloc&lt;T&gt;&gt; use it; a workaround
would be adding placement new and delete functions with adequate
signature and semantic to class T, but class T might come from another
party. Maybe even worse is the case when T has placement new and
delete functions with adequate signature but with "unknown" semantic:
I dont like to speculate about it, but whoever implements
any_container&lt;T,any_alloc&gt; and wants to use construct(..)
probably must think about it.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Replace "new" with "::new" in both cases.
</p>
<hr>
<a name="403"><h3>403.&nbsp;basic_string::swap should not throw exceptions</h3></a><p><b>Section:</b>&nbsp;21.3.5.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::swap"> [lib.string::swap]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;25 Mar 2003</p>

<p>
std::basic_string, 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a> paragraph 2 says that
basic_string "conforms to the requirements of a Sequence, as specified
in (23.1.1)." The sequence requirements specified in (23.1.1) to not
include any prohibition on swap members throwing exceptions.
</p>

<p>
Section 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> paragraph 10 does limit conditions under
which exceptions may be thrown, but applies only to "all container
types defined in this clause" and so excludes basic_string::swap
because it is defined elsewhere.
</p>

<p>
Eric Niebler points out that 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a> paragraph 5 explicitly
permits basic_string::swap to invalidates iterators, which is
disallowed by 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> paragraph 10. Thus the standard would
be contradictory if it were read or extended to read as having
basic_string meet 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> paragraph 10 requirements.
</p>

<p>
Yet several LWG members have expressed the belief that the original
intent was that basic_string::swap should not throw exceptions as
specified by 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> paragraph 10, and that the standard is
unclear on this issue. The complexity of basic_string::swap is
specified as "constant time", indicating the intent was to avoid
copying (which could cause a bad_alloc or other exception). An
important use of swap is to ensure that exceptions are not thrown in
exception-safe code.
</p>

<p>
Note: There remains long standing concern over whether or not it is
possible to reasonably meet the 23.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.requirements"> [lib.container.requirements]</a> paragraph 10 swap
requirements when allocators are unequal. The specification of
basic_string::swap exception requirements is in no way intended to
address, prejudice, or otherwise impact that concern.
</p>





<p><b>Proposed resolution:</b></p>
<p>
In 21.3.5.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::swap"> [lib.string::swap]</a>, add a throws clause:
</p>

<p>
Throws: Shall not throw exceptions.
</p>
<hr>
<a name="404"><h3>404.&nbsp;May a replacement allocation function be declared inline?</h3></a><p><b>Section:</b>&nbsp;17.4.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.replacement.functions"> [lib.replacement.functions]</a>, 18.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete"> [lib.new.delete]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;24 Apr 2003</p>
<p>
The eight basic dynamic memory allocation functions (single-object
and array versions of ::operator new and ::operator delete, in the
ordinary and nothrow forms) are replaceable.  A C++ program may
provide an alternative definition for any of them, which will be used
in preference to the implementation's definition.  
</p>

<p>
Three different parts of the standard mention requirements on
replacement functions: 17.4.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.replacement.functions"> [lib.replacement.functions]</a>, 18.5.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.single"> [lib.new.delete.single]</a>
and 18.5.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.array"> [lib.new.delete.array]</a>, and 3.7.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/basic.html#basic.stc.dynamic"> [basic.stc.dynamic]</a>.
</p>

<p>None of these three places say whether a replacement function may
  be declared inline.  18.5.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.new.delete.single"> [lib.new.delete.single]</a> paragraph 2 specifies a
  signature for the replacement function, but that's not enough:
  the <tt>inline</tt> specifier is not part of a function's signature.
  One might also reason from 7.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/dcl.html#dcl.fct.spec"> [dcl.fct.spec]</a> paragraph 2, which
  requires that "an inline function shall be defined in every
  translation unit in which it is used," but this may not be quite
  specific enough either.  We should either explicitly allow or
  explicitly forbid inline replacement memory allocation
  functions.</p>
<p><b>Proposed resolution:</b></p>
<p>
Add a new sentence to the end of 17.4.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.replacement.functions"> [lib.replacement.functions]</a> paragraph 3:
"The program's definitions shall not be specified as <tt>inline</tt>.
No diagnostic is required."
</p>

<p><i>[Kona: added "no diagnostic is required"]</i></p>

<p><b>Rationale:</b></p>
<p>
The fact that <tt>inline</tt> isn't mentioned appears to have been
nothing more than an oversight.  Existing implementations do not
permit inline functions as replacement memory allocation functions.
Providing this functionality would be difficult in some cases, and is
believed to be of limited value.
</p>
<hr>
<a name="405"><h3>405.&nbsp;qsort and POD</h3></a><p><b>Section:</b>&nbsp;25.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.c.library"> [lib.alg.c.library]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Ray Lischner&nbsp; <b>Date:</b>&nbsp;08 Apr 2003</p>
<p>
Section 25.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.c.library"> [lib.alg.c.library]</a> describes bsearch and qsort, from the C
standard library. Paragraph 4 does not list any restrictions on qsort,
but it should limit the base parameter to point to POD.  Presumably,
qsort sorts the array by copying bytes, which requires POD.
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 25.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.c.library"> [lib.alg.c.library]</a> paragraph 4, just after the declarations and
before the nonnormative note, add these words: "both of which have the
same behavior as the original declaration.  The behavior is undefined
unless the objects in the array pointed to by <i>base</i> are of POD
type."
</p>

<p><i>[Something along these lines is clearly necessary.  Matt
  provided wording.]</i></p>
<hr>
<a name="406"><h3>406.&nbsp;vector::insert(s) exception safety</h3></a><p><b>Section:</b>&nbsp;23.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.stack"> [lib.stack]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;27 Apr 2003</p>
<p>
There is a possible defect in the standard: the standard text was
never intended to prevent arbitrary ForwardIterators, whose operations
may throw exceptions, from being passed, and it also wasn't intended
to require a temporary buffer in the case where ForwardIterators were
passed (and I think most implementations don't use one).  As is, the
standard appears to impose requirements that aren't met by any
existing implementation.
</p>
<p><b>Proposed resolution:</b></p>
<p>Replace 23.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.stack"> [lib.stack]</a> paragraph 1 with:</p>
<blockquote>
  1- Notes: Causes reallocation if the new size is greater than the
  old capacity. If no reallocation happens, all the iterators and
  references before the insertion point remain valid. If an exception
  is thrown other than by the copy constructor or assignment operator
  of T or by any InputIterator operation there are no effects.
</blockquote>

<p><i>[We probably need to say something similar for deque.]</i></p>

<hr>
<a name="407"><h3>407.&nbsp;Can singular iterators be destroyed?</h3></a><p><b>Section:</b>&nbsp;24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;3 June 2003</p>
<p>
Clause 24.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.requirements"> [lib.iterator.requirements]</a>, paragraph 5, says that the only expression
that is defined for a singular iterator is "an assignment of a
non-singular value to an iterator that holds a singular value".  This 
means that destroying a singular iterator (e.g. letting an automatic
variable go out of scope) is technically undefined behavior.  This
seems overly strict, and probably unintentional.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the sentence in question to "... the only exceptions are
destroying an iterator that holds a singular value, or the assignment
of a non-singular value to an iterator that holds a singular value."
</p>
<hr>
<a name="409"><h3>409.&nbsp;Closing an fstream should clear error state</h3></a><p><b>Section:</b>&nbsp;27.8.1.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ifstream.members"> [lib.ifstream.members]</a>, 27.8.1.10 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ofstream.members"> [lib.ofstream.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Nathan Myers&nbsp; <b>Date:</b>&nbsp;3 June 2003</p>
<p>
A strict reading of 27.8.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstreams"> [lib.fstreams]</a> shows that opening or
closing a basic_[io]fstream does not affect the error bits.  This
means, for example, that if you read through a file up to EOF, and
then close the stream and reopen it at the beginning of the file,
the EOF bit in the stream's error state is still set.  This is
counterintuitive.
</p>
<p>
The LWG considered this issue once before, as issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#22">22</a>,
and put in a footnote to clarify that the strict reading was indeed
correct.  We did that because we believed the standard was
unambiguous and consistent, and that we should not make architectural
changes in a TC.  Now that we're working on a new revision of the
language, those considerations no longer apply.
</p>
<p><b>Proposed resolution:</b></p>

<p>Change 27.8.1.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ifstream.members"> [lib.ifstream.members]</a>, para. 3 from:</p>

<blockquote>
Calls rdbuf()-&gt;open(s,mode|in). If that function returns a null
pointer, calls setstate(failbit) (which may throw ios_base::failure
[Footnote: (lib.iostate.flags)].
</blockquote>

<p>to:</p>

<blockquote>Calls rdbuf()-&gt;open(s,mode|in). If that function returns
a null pointer, calls setstate(failbit) (which may throw
ios_base::failure [Footnote: (lib.iostate.flags)), else calls clear().
</blockquote>

<p>Change 27.8.1.10 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ofstream.members"> [lib.ofstream.members]</a>, para. 3 from:</p>

<blockquote>Calls rdbuf()-&gt;open(s,mode|out). If that function
returns a null pointer, calls setstate(failbit) (which may throw
ios_base::failure [Footnote: (lib.iostate.flags)).
</blockquote>

<p>to:</p>

<blockquote>Calls rdbuf()-&gt;open(s,mode|out). If that function
returns a null pointer, calls setstate(failbit) (which may throw
ios_base::failure [Footnote: (lib.iostate.flags)), else calls clear().
</blockquote>

<p>Change 27.8.1.13 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstream.members"> [lib.fstream.members]</a>, para. 3 from:</p>

<blockquote>Calls rdbuf()-&gt;open(s,mode), If that function returns a
null pointer, calls setstate(failbit), (which may throw
ios_base::failure). (lib.iostate.flags) )
</blockquote>

<p>to:</p>

<blockquote>Calls rdbuf()-&gt;open(s,mode), If that function returns a
null pointer, calls setstate(failbit), (which may throw
ios_base::failure). (lib.iostate.flags) ), else calls clear().
</blockquote>



<p><i>[Kona: the LWG agrees this is a good idea.  Post-Kona: Bill
provided wording.  He suggests having open, not close, clear the error
flags.]</i></p>

<p><i>[Post-Sydney: Howard provided a new proposed resolution.  The
  old one didn't make sense because it proposed to fix this at the
  level of basic_filebuf, which doesn't have access to the stream's
  error state.  Howard's proposed resolution fixes this at the level
  of the three fstream class template instead.]</i></p>

<hr>
<a name="410"><h3>410.&nbsp;Missing semantics for stack and queue comparison operators</h3></a><p><b>Section:</b>&nbsp;23.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.cons"> [lib.list.cons]</a>, 23.2.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.modifiers"> [lib.list.modifiers]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Hans Bos&nbsp; <b>Date:</b>&nbsp;7 Jun 2003</p>
<p>
Sections 23.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.cons"> [lib.list.cons]</a> and 23.2.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.modifiers"> [lib.list.modifiers]</a> list
comparison operators (==, !=, &lt;, &lt;=, &gt;, =&gt;) for queue and
stack.  Only the semantics for queue::operator== (23.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.cons"> [lib.list.cons]</a> par2) and queue::operator&lt; (23.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.cons"> [lib.list.cons]</a>
par3) are defined.
</p>
<p><b>Proposed resolution:</b></p>

<p>Add the following new paragraphs after 23.2.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.cons"> [lib.list.cons]</a>
  paragraph 3:</p>

<blockquote>

<pre>  operator!=
</pre>
<p>Returns: <tt>x.c != y.c</tt></p>

<pre>  operator&gt;
</pre>
<p>Returns: <tt>x.c &gt; y.c</tt></p>

<pre>  operator&lt;=
</pre>
<p>Returns: <tt>x.c &lt;= y.c</tt></p>

<pre>  operator&gt;=
</pre>
<p>Returns: <tt>x.c &gt;= y.c</tt></p>

</blockquote>

<p>Add the following paragraphs at the end of 23.2.3.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.list.modifiers"> [lib.list.modifiers]</a>:</p>

<blockquote>

<pre>  operator==
</pre>
<p>Returns: <tt>x.c == y.c</tt></p>

<pre>  operator&lt;
</pre>
<p>Returns: <tt>x.c &lt; y.c</tt></p>

<pre>  operator!=
</pre>
<p>Returns: <tt>x.c != y.c</tt></p>

<pre>  operator&gt;
</pre>
<p>Returns: <tt>x.c &gt; y.c</tt></p>

<pre>  operator&lt;=
</pre>
<p>Returns: <tt>x.c &lt;= y.c</tt></p>

<pre>  operator&gt;=
</pre>
<p>Returns: <tt>x.c &gt;= y.c</tt></p>

</blockquote>


<p><i>[Kona: Matt provided wording.]</i></p>

<p><b>Rationale:</b></p>
There isn't any real doubt about what these operators are
supposed to do, but we ought to spell it out.
<hr>
<a name="411"><h3>411.&nbsp;Wrong names of set member functions</h3></a><p><b>Section:</b>&nbsp;25.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.set.operations"> [lib.alg.set.operations]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Daniel Frey&nbsp; <b>Date:</b>&nbsp;9 Jul 2003</p>
<p>
25.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.set.operations"> [lib.alg.set.operations]</a> paragraph 1 reads:
"The semantics of the set operations are generalized to multisets in a 
standard way by defining union() to contain the maximum number of 
occurrences of every element, intersection() to contain the minimum, and 
so on."
</p>

<p>
This is wrong.  The name of the functions are set_union() and
set_intersection(), not union() and intersection().
</p>
<p><b>Proposed resolution:</b></p>
<p>Change that sentence to use the correct names.</p>
<hr>
<a name="412"><h3>412.&nbsp;Typo in 27.4.4.3</h3></a><p><b>Section:</b>&nbsp;27.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostate.flags"> [lib.iostate.flags]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;10 Jul 2003</p>
<p>
The Effects clause in 27.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostate.flags"> [lib.iostate.flags]</a> paragraph 5 says that the
function only throws if the respective bits are already set prior to
the function call. That's obviously not the intent. The typo ought to
be corrected and the text reworded as: "If (<i>state</i> &amp;
exceptions()) == 0, returns. ..."
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 27.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostate.flags"> [lib.iostate.flags]</a> paragraph 5, replace "If (rdstate() &amp;
exceptions()) == 0" with "If ((state | (rdbuf() ? goodbit : badbit))
&amp; exceptions()) == 0".
</p>

<p><i>[Kona: the original proposed resolution wasn't quite right.  We
  really do mean rdstate(); the ambiguity is that the wording in the
  standard doesn't make it clear whether we mean rdstate() before
  setting the new state, or rdsate() after setting it.  We intend the
  latter, of course. Post-Kona: Martin provided wording.]</i></p>

<hr>
<a name="413"><h3>413.&nbsp;Proposed resolution to LDR#64 still wrong</h3></a><p><b>Section:</b>&nbsp;27.6.1.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream::extractors"> [lib.istream::extractors]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Bo Persson&nbsp; <b>Date:</b>&nbsp;13 Jul 2003</p>
<p>
The second sentence of the proposed resolution says:
</p>

<p>
"If it inserted no characters because it caught an exception thrown
while extracting characters from sb and ..."
</p>

<p>
However, we are not extracting from sb, but extracting from the
basic_istream (*this) and inserting into sb. I can't really tell if
"extracting" or "sb" is a typo.
</p>

<p><i>[
Sydney: Definitely a real issue. We are, indeed, extracting characters
from an istream and not from sb. The problem was there in the FDIS and
wasn't fixed by issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#64">64</a>. Probably what was intended was
to have *this instead of sb. We're talking about the exception flag
state of a basic_istream object, and there's only one basic_istream
object in this discussion, so that would be a consistent
interpretation.  (But we need to be careful: the exception policy of
this member function must be consistent with that of other
extractors.)  PJP will provide wording.
]</i></p>

<p><b>Proposed resolution:</b></p>
<p>Change the sentence from:</p>

<blockquote>
If it inserted no characters because it caught an exception thrown
while extracting characters from sb and failbit is on in exceptions(),
then the caught exception is rethrown.
</blockquote>

<p>to:</p>

<blockquote>
If it inserted no characters because it caught an exception thrown
while extracting characters from *this and failbit is on in exceptions(),
then the caught exception is rethrown.
</blockquote>
<hr>
<a name="414"><h3>414.&nbsp;Which iterators are invalidated by v.erase()?</h3></a><p><b>Section:</b>&nbsp;23.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.stack"> [lib.stack]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;19 Aug 2003</p>
<p>
Consider the following code fragment:
</p>
<blockquote>
<pre>int A[8] = { 1,3,5,7,9,8,4,2 };
std::vector&lt;int&gt; v(A, A+8);

std::vector&lt;int&gt;::iterator i1 = v.begin() + 3;
std::vector&lt;int&gt;::iterator i2 = v.begin() + 4;
v.erase(i1);
</pre>
</blockquote>

<p>
Which iterators are invalidated by <tt>v.erase(i1)</tt>: i1, i2,
both, or neither?
</p>

<p>
On all existing implementations that I know of, the status of i1 and
i2 is the same: both of them will be iterators that point to some
elements of the vector (albeit not the same elements they did
before).  You won't get a crash if you use them.  Depending on 
exactly what you mean by "invalidate", you might say that neither one
has been invalidated because they still point to <i>something</i>,
or you might say that both have been invalidated because in both
cases the elements they point to have been changed out from under the
iterator.
</p>

<p>
The standard doesn't say either of those things.  It says that erase
invalidates all iterators and references "after the point of the
erase".  This doesn't include i1, since it's at the point of the
erase instead of after it.  I can't think of any sensible definition
of invalidation by which one can say that i2 is invalidated but i1
isn't.
</p>

<p>
(This issue is important if you try to reason about iterator validity
based only on the guarantees in the standard, rather than reasoning
from typical implementation techniques.  Strict debugging modes,
which some programmers find useful, do not use typical implementation
techniques.)
</p>
<p><b>Proposed resolution:</b></p>
<p>
In 23.2.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.stack"> [lib.stack]</a> paragraph 3, change "Invalidates all the
iterators and references after the point of the erase" to
"Invalidates iterators and references at or after the point of the
erase". 
</p>
<p><b>Rationale:</b></p>
<p>I believe this was essentially a typographical error, and that it
  was taken for granted that erasing an element invalidates iterators
  that point to it.  The effects clause in question treats iterators
  and references in parallel, and it would seem counterintuitive to
  say that a reference to an erased value remains valid.</p>
<hr>
<a name="415"><h3>415.&nbsp;behavior of std::ws</h3></a><p><b>Section:</b>&nbsp;27.6.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.manip"> [lib.istream.manip]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;18 Sep 2003</p>
<p>
According to 27.6.1.4, the ws() manipulator is not required to construct
the sentry object. The manipulator is also not a member function so the
text in 27.6.1, p1 through 4 that describes the exception policy for
istream member functions does not apply. That seems inconsistent with
the rest of extractors and all the other input functions (i.e., ws will
not cause a tied stream to be flushed before extraction, it doesn't check
the stream's exceptions or catch exceptions thrown during input, and it
doesn't affect the stream's gcount).
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add to 27.6.1.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.manip"> [lib.istream.manip]</a>, immediately before the first sentence
of paragraph 1, the following text:
</p>

    <blockquote>
    Behaves as an unformatted input function (as described in
    27.6.1.3, paragraph 1), except that it does not count the number
    of characters extracted and does not affect the value returned by
    subsequent calls to is.gcount(). After constructing a sentry
    object...  
    </blockquote>

<p><i>[Post-Kona: Martin provided wording]</i></p>

<hr>
<a name="420"><h3>420.&nbsp;is std::FILE a complete type?</h3></a><p><b>Section:</b>&nbsp;27.8.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstreams"> [lib.fstreams]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;18 Sep 2003</p>
<p>
7.19.1, p2, of C99 requires that the FILE type only be declared in
&lt;stdio.h&gt;.  None of the (implementation-defined) members of the
struct is mentioned anywhere for obvious reasons.
</p>

<p>
C++ says in 27.8.1, p2 that FILE is a type that's defined in &lt;cstdio&gt;. Is
it really the intent that FILE be a complete type or is an implementation
allowed to just declare it without providing a full definition?
</p>
<p><b>Proposed resolution:</b></p>
<p>In the first sentence of 27.8.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstreams"> [lib.fstreams]</a> paragraph 2, change
  "defined" to "declared".</p>
<p><b>Rationale:</b></p>
<p>We don't want to impose any restrictions beyond what the C standard
  already says. We don't want to make anything implementation defined,
  because that imposes new requirements in implementations.</p>
<hr>
<a name="425"><h3>425.&nbsp;return value of std::get_temporary_buffer</h3></a><p><b>Section:</b>&nbsp;20.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.help"> [lib.meta.help]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;18 Sep 2003</p>
<p>
The standard is not clear about the requirements on the value returned from
a call to get_temporary_buffer(0). In particular, it fails to specify whether
the call should return a distinct pointer each time it is called (like
operator new), or whether the value is unspecified (as if returned by
malloc). The standard also fails to mention what the required behavior
is when the argument is less than 0.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change 20.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-utilities.html#lib.meta.help"> [lib.meta.help]</a> paragraph 2 from "...or a pair of 0
values if no storage can be obtained" to "...or a pair of 0 values if
no storage can be obtained or if <i>n</i> &lt;= 0."</p>
<p><i>[Kona: Matt provided wording]</i></p>
<hr>
<a name="426"><h3>426.&nbsp;search_n(), fill_n(), and generate_n() with negative n</h3></a><p><b>Section:</b>&nbsp;25.1.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.search"> [lib.alg.search]</a>, 25.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.fill"> [lib.alg.fill]</a>, 25.2.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.generate"> [lib.alg.generate]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;18 Sep 2003</p>
<p>
The complexity requirements for these function templates are incorrect
(or don't even make sense) for negative n:</p>

<p>25.1.9, p7 (search_n):
<br>
Complexity: At most (last1 - first1) * count applications
of the corresponding predicate.</p>

<p>25.2.5, p3 (fill_n):
<br>
Complexity: Exactly last - first (or n) assignments.</p>
<br>

<p>25.2.6, p3 (generate_n):
<br>
Complexity: Exactly last - first (or n) assignments.</p>

<p>
In addition, the Requirements or the Effects clauses for the latter two
templates don't say anything about the behavior when n is negative.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change 25.1.9, p7 to</p>

<blockquote>
Complexity: At most (last1 - first1) * count applications
of the corresponding predicate if count is positive,
or 0 otherwise.
</blockquote>

<p>Change 25.2.5, p2 to</p>
<blockquote>
Effects: Assigns value through all the iterators in the range [first,
last), or [first, first + n) if n is positive, none otherwise.
</blockquote>

<p>Change 25.2.5, p3 to:</p>
<blockquote>
Complexity: Exactly last - first (or n if n is positive,
or 0 otherwise) assignments.
</blockquote>

<p>
Change 25.2.6, p1 
to (notice the correction for the misspelled "through"):
</p>
<blockquote>
Effects: Invokes the function object genand assigns the return
value of gen through all the iterators in the range [first, last),
or [first, first + n) if n is positive, or [first, first)
otherwise.
</blockquote>

<p>Change 25.2.6, p3 to:</p>
<blockquote>
Complexity: Exactly last - first (or n if n is positive,
or 0 otherwise) assignments.
</blockquote>
<p><b>Rationale:</b></p>
<p>Informally, we want to say that whenever we see a negative number
  we treat it the same as if it were zero.  We believe the above
  changes do that (although they may not be the minimal way of saying
  so).  The LWG considered and rejected the alternative of saying that
  negative numbers are undefined behavior.</p>
<hr>
<a name="428"><h3>428.&nbsp;string::erase(iterator) validity</h3></a><p><b>Section:</b>&nbsp;21.3.5.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::erase"> [lib.string::erase]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;18 Sep 2003</p>
<p>
23.1.1, p3 along with Table 67 specify as a prerequisite for a.erase(q)
that q must be a valid dereferenceable iterator into the sequence a.
</p>

<p>
However, 21.3.5.5, p5 describing string::erase(p) only requires that
p be a valid iterator.
</p>

<p>
This may be interepreted as a relaxation of the general requirement,
which is most likely not the intent.
</p>
<p><b>Proposed resolution:</b></p>
<p>Remove 21.3.5.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::erase"> [lib.string::erase]</a> paragraph 5.</p>
<p><b>Rationale:</b></p>
<p>The LWG considered two options: changing the string requirements to
  match the general container requirements, or just removing the
  erroneous string requirements altogether.  The LWG chose the latter
  option, on the grounds that duplicating text always risks the
  possibility that it might be duplicated incorrectly.</p>
<hr>
<a name="432"><h3>432.&nbsp;stringbuf::overflow() makes only one write position available</h3></a><p><b>Section:</b>&nbsp;27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Christian W Brock&nbsp; <b>Date:</b>&nbsp;24 Sep 2003</p>
<p>27.7.1.3 par 8 says:</p>
<blockquote>
Notes: The function can make a write position available only if
    ( mode &amp; ios_base::out) != 0. To make a write position
    available, the function reallocates (or initially allocates) an
    array object with a sufficient number of elements to hold the
    current array object (if any), plus one additional write position.
    If ( mode &amp; ios_base::in) != 0, the function alters the read end
    pointer egptr() to point just past the new write position (as
    does the write end pointer epptr()).
</blockquote>

<p>
The sentences "plus one additional write position." and especially
    "(as does the write end pointer epptr())" COULD by interpreted
    (and is interpreted by at least my library vendor) as:
</p>

<blockquote>
    post-condition: epptr() == pptr()+1
</blockquote>

<p>
This WOULD force sputc() to call the virtual overflow() each time.
</p>

<p>The proposed change also affects Defect Report 169.</p>

<p><b>Proposed resolution:</b></p>
<p>27.7.1.1/2 Change:</p>

<blockquote>
2- Notes: The function allocates no array object.
</blockquote>

<p>
to:
</p>

<blockquote>
2- Postcondition: str() == "".
</blockquote>

<p>
27.7.1.1/3 Change:
</p>

<blockquote>
<p>
-3- Effects: Constructs an object of class basic_stringbuf,
initializing the base class with basic_streambuf()
(lib.streambuf.cons), and initializing mode with which . Then copies
the content of str into the basic_stringbuf underlying character
sequence and initializes the input and output sequences according to
which. If which &amp; ios_base::out is true, initializes the output
sequence with the underlying sequence. If which &amp; ios_base::in is
true, initializes the input sequence with the underlying sequence.
</p>
</blockquote>

<p>to:</p>

<blockquote>
<p>
-3- Effects: Constructs an object of class basic_stringbuf,
initializing the base class with basic_streambuf()
(lib.streambuf.cons), and initializing mode with which. Then copies
the content of str into the basic_stringbuf underlying character
sequence. If which &amp; ios_base::out is true, initializes the output
sequence such that pbase() points to the first underlying character,
epptr() points one past the last underlying character, and if (which &amp;
ios_base::ate) is true, pptr() is set equal to
epptr() else pptr() is set equal to pbase(). If which &amp; ios_base::in
is true, initializes the input sequence such that eback() and gptr()
point to the first underlying character and egptr() points one past
the last underlying character.
</p>
</blockquote>

<p>27.7.1.2/1 Change:</p>

<blockquote>
<p>
-1- Returns: A basic_string object whose content is equal to the
basic_stringbuf underlying character sequence. If the buffer is only
created in input mode, the underlying character sequence is equal to
the input sequence; otherwise, it is equal to the output sequence. In
case of an empty underlying character sequence, the function returns
basic_string&lt;charT,traits,Allocator&gt;().
</p>
</blockquote>

<p>to:</p>

<blockquote>
<p>
-1- Returns: A basic_string object whose content is equal to the
basic_stringbuf underlying character sequence. If the basic_stringbuf
was created only in input mode, the resultant basic_string contains
the character sequence in the range [eback(), egptr()).  If the
basic_stringbuf was created with (which &amp; ios_base::out) being true
then the resultant basic_string contains the character sequence in the
range [pbase(), high_mark) where high_mark represents the position one
past the highest initialized character in the buffer.  Characters can
be initialized either through writing to the stream, or by
constructing the basic_stringbuf with a basic_string, or by calling
the str(basic_string) member function.  In the case of calling the
str(basic_string) member function, all characters initialized prior to
the call are now considered uninitialized (except for those
characters re-initialized by the new basic_string).  Otherwise the
basic_stringbuf has been created in neither input nor output mode and
a zero length basic_string is returned.
</p>
</blockquote>

<p>
27.7.1.2/2 Change:
</p>

<blockquote>
<p>
-2- Effects: If the basic_stringbuf's underlying character sequence is
not empty, deallocates it. Then copies the content of s into the
basic_stringbuf underlying character sequence and initializes the
input and output sequences according to the mode stored when creating
the basic_stringbuf object. If (mode&amp;ios_base::out) is true, then
initializes the output sequence with the underlying sequence. If
(mode&amp;ios_base::in) is true, then initializes the input sequence with
the underlying sequence.
</p>
</blockquote>

<p>to:</p>

<blockquote>
<p>
-2- Effects: Copies the content of s into the basic_stringbuf
underlying character sequence. If mode &amp; ios_base::out is true,
initializes the output sequence such that pbase() points to the first
underlying character, epptr() points one past the last underlying
character, and if (mode &amp; ios_base::ate) is true,
pptr() is set equal to epptr() else pptr() is set equal to pbase(). If
mode &amp; ios_base::in is true, initializes the input sequence such that
eback() and gptr() point to the first underlying character and egptr()
points one past the last underlying character.
</p>
</blockquote>

<p>Remove 27.2.1.2/3.  (Same rationale as issue 238: incorrect and unnecessary.)</p>

<p>27.7.1.3/1 Change:</p>

<blockquote>
<p>
1- Returns: If the input sequence has a read position available,
returns traits::to_int_type(*gptr()).  Otherwise, returns
traits::eof().
</p>
</blockquote>

<p>to:</p>

<blockquote>
<p>
1- Returns: If the input sequence has a read position available,
returns traits::to_int_type(*gptr()).  Otherwise, returns
traits::eof().  Any character in the underlying buffer which has been
initialized is considered to be part of the input sequence.
</p>
</blockquote>

<p>27.7.1.3/9 Change:</p>

<blockquote>
<p>
-9- Notes: The function can make a write position available only if (
mode &amp; ios_base::out) != 0. To make a write position available, the
function reallocates (or initially allocates) an array object with a
sufficient number of elements to hold the current array object (if
any), plus one additional write position. If ( mode &amp; ios_base::in) !=
0, the function alters the read end pointer egptr() to point just past
the new write position (as does the write end pointer epptr()).
</p>
</blockquote>

<p>to:</p>

<blockquote>
<p>
-9- The function can make a write position available only if ( mode &amp;
ios_base::out) != 0. To make a write position available, the function
reallocates (or initially allocates) an array object with a sufficient
number of elements to hold the current array object (if any), plus one
additional write position. If ( mode &amp; ios_base::in) != 0, the
function alters the read end pointer egptr() to point just past the
new write position.
</p>
</blockquote>

<p>27.7.1.3/12 Change:</p>

<blockquote>
<p>
-12- _ If (newoff + off) &lt; 0, or (xend - xbeg) &lt; (newoff + off), the
positioning operation fails. Otherwise, the function assigns xbeg +
newoff + off to the next pointer xnext .
</p>
</blockquote>

<p>to:</p>

<blockquote>
<p>
-12- _ If (newoff + off) &lt; 0, or if (newoff + off) refers to an
uninitialized character (as defined in 27.7.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.members"> [lib.stringbuf.members]</a>
paragraph 1), the positioning operation fails. Otherwise, the function
assigns xbeg + newoff + off to the next pointer xnext .
</p>
</blockquote>

<p><i>[post-Kona: Howard provided wording.  At Kona the LWG agreed that
  something along these lines was a good idea, but the original
  proposed resolution didn't say enough about the effect of various
  member functions on the underlying character sequences.]</i></p>

<p><b>Rationale:</b></p>
<p>The current basic_stringbuf description is over-constrained in such
a way as to prohibit vendors from making this the high-performance
in-memory stream it was meant to be.  The fundamental problem is that
the pointers: eback(), gptr(), egptr(), pbase(), pptr(), epptr() are
observable from a derived client, and the current description
restricts the range [pbase(), epptr()) from being grown geometrically.
This change allows, but does not require, geometric growth of this
range.</p>

<p>Backwards compatibility issues: These changes will break code that
derives from basic_stringbuf, observes epptr(), and depends upon
[pbase(), epptr()) growing by one character on each call to overflow()
(i.e. test suites).  Otherwise there are no backwards compatibility
issues.</p>

<p>27.7.1.1/2: The non-normative note is non-binding, and if it were
binding, would be over specification.  The recommended change focuses
on the important observable fact.</p>

<p>27.7.1.1/3: This change does two things: 1.  It describes exactly
what must happen in terms of the sequences.  The terms "input
sequence" and "output sequence" are not well defined.  2.  It
introduces a common extension: open with app or ate mode.  I concur
with issue 238 that paragraph 4 is both wrong and unnecessary.</p>

<p>27.7.1.2/1: This change is the crux of the efficiency issue.  The
resultant basic_string is not dependent upon epptr(), and thus
implementors are free to grow the underlying buffer geometrically
during overflow() *and* place epptr() at the end of that buffer.</p>

<p>27.7.1.2/2:  Made consistent with the proposed 27.7.1.1/3.</p>

<p>27.7.1.3/1: Clarifies that characters written to the stream beyond
the initially specified string are available for reading in an i/o
basic_streambuf.</p>

<p>27.7.1.3/9: Made normative by removing "Notes:", and removed the
trailing parenthetical comment concerning epptr().</p>

<p>27.7.1.3/12: Restricting the positioning to [xbeg, xend) is no
longer allowable since [pbase(), epptr()) may now contain
uninitialized characters.  Positioning is only allowable over the
initialized range.</p>
<hr>
<a name="434"><h3>434.&nbsp;bitset::to_string() hard to use</h3></a><p><b>Section:</b>&nbsp;23.3.5.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.members"> [lib.bitset.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;15 Oct 2003</p>
<p>
It has been pointed out a number of times that the bitset to_string() member
function template is tedious to use since callers must explicitly specify the
entire template argument list (3 arguments). At least two implementations
provide a number of overloads of this template to make it easier to use.
</p>
<p><b>Proposed resolution:</b></p>
<p>In order to allow callers to specify no template arguments at all, just the
first one (charT), or the first 2 (charT and traits), in addition to all
three template arguments, add the following three overloads to both the
interface (declarations only) of the class template bitset as well as to
section 23.3.5.2, immediately after p34, the Returns clause of the existing
to_string() member function template:</p>

<pre>    template &lt;class charT, class traits&gt;
    basic_string&lt;charT, traits, allocator&lt;charT&gt; &gt;
    to_string () const;

    -34.1- Returns: to_string&lt;charT, traits, allocator&lt;charT&gt; &gt;().

    template &lt;class charT&gt;
    basic_string&lt;charT, char_traits&lt;charT&gt;, allocator&lt;charT&gt; &gt;
    to_string () const;

    -34.2- Returns: to_string&lt;charT, char_traits&lt;charT&gt;, allocator&lt;charT&gt; &gt;().

    basic_string&lt;char, char_traits&lt;char&gt;, allocator&lt;char&gt; &gt;
    to_string () const;

    -34.3- Returns: to_string&lt;char, char_traits&lt;char&gt;, allocator&lt;char&gt; &gt;().
</pre>

<p><i>[Kona: the LWG agrees that this is an improvement over the
  status quo.  Dietmar thought about an alternative using a proxy
  object but now believes that the proposed resolution above is the
  right choice.
]</i></p>

<hr>
<a name="435"><h3>435.&nbsp;bug in DR 25</h3></a><p><b>Section:</b>&nbsp;21.3.7.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string.io"> [lib.string.io]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;15 Oct 2003</p>

<p>
It has been pointed out that the proposed resolution in DR 25 may not be
quite up to snuff: <br>
http://gcc.gnu.org/ml/libstdc++/2003-09/msg00147.html
http://anubis.dkuug.dk/jtc1/sc22/wg21/docs/lwg-defects.html#25<br>
</p>

<p>
It looks like Petur is right. The complete corrected text is copied below.
I think we may have have been confused by the reference to 22.2.2.2.2 and
the subsequent description of `n' which actually talks about the second
argument to sputn(), not about the number of fill characters to pad with.
</p>

<p>
So the question is: was the original text correct? If the intent was to
follow classic iostreams then it most likely wasn't, since setting width()
to less than the length of the string doesn't truncate it on output. This
is also the behavior of most implementations (except for SGI's standard
iostreams where the operator does truncate).
</p>
<p><b>Proposed resolution:</b></p>
<p>Change the text in 21.3.7.9, p4 from</p>
    <blockquote>
    If bool(k) is true, inserts characters as if by calling
    os.rdbuf()-&gt;sputn(str.data(), n), padding as described in stage 3
    of lib.facet.num.put.virtuals, where n is the larger of os.width()
    and str.size(); 
    </blockquote>
<p>to</p>
    <blockquote>
    If bool(k) is true, determines padding as described in
    lib.facet.num.put.virtuals, and then inserts the resulting
    sequence of characters <tt>seq</tt> as if by calling
    <tt>os.rdbuf()-&gt;sputn(seq, n)</tt>, where <tt>n</tt> is the larger of
    <tt>os.width()</tt> and <tt>str.size()</tt>;
     </blockquote>

<p><i>[Kona: it appears that neither the original wording, DR25, nor the
  proposed resolution, is quite what we want.  We want to say that
  the string will be output, padded to os.width() if necessary.  We
  don't want to duplicate the padding rules in clause 22, because
  they're complicated, but we need to be careful because they weren't
  quite written with quite this case in mind.  We need to say what
  the character sequence is, and then defer to clause 22.  Post-Kona:
  Benjamin provided wording.]</i></p>

<hr>
<a name="436"><h3>436.&nbsp;are cv-qualified facet types valid facets?</h3></a><p><b>Section:</b>&nbsp;22.1.1.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.facet"> [lib.locale.facet]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;15 Oct 2003</p>
<p>
Is "const std::ctype&lt;char&gt;" a valid template argument to has_facet, use_facet,
and the locale template ctor? And if so, does it designate the same Facet as
the non-const "std::ctype&lt;char&gt;?" What about "volatile std::ctype&lt;char&gt;?"
Different implementations behave differently: some fail to compile, others
accept such types but behave inconsistently.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change 22.1.1.1.2, p1 to read:</p>

<p>Template parameters in this clause which are required to be facets
are those named Facet in declarations. A program that passes a type
that is not a facet, or a type that refers to volatile-qualified
facet, as an (explicit or deduced) template parameter to a locale
function expecting a facet, is ill-formed.  A const-qualified facet is
a valid template argument to any locale function that expects a Facet
template parameter.</p>

<p><i>[Kona: changed the last sentence from a footnote to normative
text.]</i></p>

<hr>
<a name="438"><h3>438.&nbsp;Ambiguity in the "do the right thing" clause</h3></a><p><b>Section:</b>&nbsp;23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;20 Oct 2003</p>

<p>Section 23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a>, paragraphs 9-11, fixed up the problem
noticed with statements like:</p>
<pre>vector&lt;int&gt; v(10, 1);
</pre>

<p>The intent of the above statement was to construct with:</p>
<pre>vector(size_type, const value_type&amp;);
</pre>

<p>but early implementations failed to compile as they bound to:</p>
<pre>template &lt;class InputIterator&gt;
vector(InputIterator f, InputIterator l);
</pre>
<p>instead.</p>

<p>Paragraphs 9-11 say that if InputIterator is an integral type, then the
member template constructor will have the same effect as:</p>
<pre>vector&lt;static_cast&lt;size_type&gt;(f), static_cast&lt;value_type&gt;(l));
</pre>
<p>(and similarly for the other member template functions of sequences).</p>

<p>There is also a note that describes one implementation technique:</p>
<blockquote>
   One way that sequence implementors can satisfy this requirement is to
   specialize the member template for every integral type.
</blockquote>

<p>This might look something like:</p>
<blockquote>
<pre>template &lt;class T&gt;
struct vector
{
     typedef unsigned size_type;

     explicit vector(size_type) {}
     vector(size_type, const T&amp;) {}

     template &lt;class I&gt;
     vector(I, I);

     // ...
};

template &lt;class T&gt;
template &lt;class I&gt;
vector&lt;T&gt;::vector(I, I) { ... }

template &lt;&gt;
template &lt;&gt;
vector&lt;int&gt;::vector(int, int) { ... }

template &lt;&gt;
template &lt;&gt;
vector&lt;int&gt;::vector(unsigned, unsigned) { ... }

//  ...
</pre>
</blockquote>

<p>Label this solution 'A'.</p>

<p>The standard also says:</p>
<blockquote>
 Less cumbersome implementation techniques also exist.
</blockquote>
<p>
A popular technique is to not specialize as above, but instead catch
every call with the member template, detect the type of InputIterator,
and then redirect to the correct logic.  Something like:
</p>
<blockquote>
<pre>template &lt;class T&gt;
template &lt;class I&gt;
vector&lt;T&gt;::vector(I f, I l)
{
     choose_init(f, l, int2type&lt;is_integral&lt;I&gt;::value&gt;());
}

template &lt;class T&gt;
template &lt;class I&gt;
vector&lt;T&gt;::choose_init(I f, I l, int2type&lt;false&gt;)
{
    // construct with iterators
}

template &lt;class T&gt;
template &lt;class I&gt;
vector&lt;T&gt;::choose_init(I f, I l, int2type&lt;true&gt;)
{
    size_type sz = static_cast&lt;size_type&gt;(f);
    value_type v = static_cast&lt;value_type&gt;(l);
    // construct with sz,v
}
</pre>
</blockquote>

<p>Label this solution 'B'.</p>

<p>Both of these solutions solve the case the standard specifically
mentions:</p>
<pre>vector&lt;int&gt; v(10, 1);  // ok, vector size 10, initialized to 1
</pre>

<p>
However, (and here is the problem), the two solutions have different
behavior in some cases where the value_type of the sequence is not an
integral type.  For example consider:
</p>
<blockquote><pre>     pair&lt;char, char&gt;                     p('a', 'b');
     vector&lt;vector&lt;pair&lt;char, char&gt; &gt; &gt;   d('a', 'b');
</pre></blockquote>
<p>
The second line of this snippet is likely an error.  Solution A catches
the error and refuses to compile.  The reason is that there is no
specialization of the member template constructor that looks like:
</p>
<pre>template &lt;&gt;
template &lt;&gt;
vector&lt;vector&lt;pair&lt;char, char&gt; &gt; &gt;::vector(char, char) { ... }
</pre>

<p>
So the expression binds to the unspecialized member template
constructor, and then fails (compile time) because char is not an
InputIterator.
</p>

<p>
Solution B compiles the above example though.  'a' is casted to an
unsigned integral type and used to size the outer vector.  'b' is
static casted to the inner vector using it's explicit constructor:
</p>

<pre>explicit vector(size_type n);
</pre>

<p>
and so you end up with a static_cast&lt;size_type&gt;('a') by
static_cast&lt;size_type&gt;('b') matrix.
</p>

<p>
It is certainly possible that this is what the coder intended.  But the
explicit qualifier on the inner vector has been thwarted at any rate.
</p>

<p>
The standard is not clear whether the expression:
</p>

<pre>     vector&lt;vector&lt;pair&lt;char, char&gt; &gt; &gt;   d('a', 'b');
</pre>

<p>
(and similar expressions) are:
</p>

<ol>
<li>  undefined behavior.</li>
<li>  illegal and must be rejected.</li>
<li>  legal and must be accepted.</li>
</ol>

<p>My preference is listed in the order presented.</p>

<p>There are still other techniques for implementing the requirements of
paragraphs 9-11, namely the "restricted template technique" (e.g.
enable_if).  This technique is the most compact and easy way of coding
the requirements, and has the behavior of #2 (rejects the above
expression).
</p>

<p>
Choosing 1 would allow all implementation techniques I'm aware of.
Choosing 2 would allow only solution 'A' and the enable_if technique.
Choosing 3 would allow only solution 'B'.
</p>

<p>
Possible wording for a future standard if we wanted to actively reject
the expression above would be to change "static_cast" in paragraphs
9-11 to "implicit_cast" where that is defined by:
</p>

<blockquote>
<pre>template &lt;class T, class U&gt;
inline
T implicit_cast(const U&amp; u)
{
     return u;
}
</pre>
</blockquote>

<p><b>Proposed resolution:</b></p>

Replace 23.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.sequence.reqmts"> [lib.sequence.reqmts]</a> paragraphs 9 - 11 with:

<p>For every sequence defined in this clause and in clause lib.strings:</p>

<ul>
  <li>
    <p>If the constructor</p>
       <pre>       template &lt;class InputIterator&gt;
       X(InputIterator f, InputIterator l,
         const allocator_type&amp; a = allocator_type())
       </pre>
    <p>is called with a type InputIterator that does not qualify as
    an input iterator, then the constructor will behave as if the
    overloaded constructor:</p>
       <pre>       X(size_type, const value_type&amp; = value_type(),
         const allocator_type&amp; = allocator_type())
       </pre>
    <p>were called instead, with the arguments static_cast&lt;size_type&gt;(f), l and a, respectively.</p>
  </li>

  <li>
    <p>If the member functions of the forms:</p>
       <pre>       template &lt;class InputIterator&gt;          //  such as  insert()
       rt fx1(iterator p, InputIterator f, InputIterator l);

       template &lt;class InputIterator&gt;          //  such as  append(), assign()
       rt fx2(InputIterator f, InputIterator l);

       template &lt;class InputIterator&gt;          //  such as  replace()
       rt fx3(iterator i1, iterator i2, InputIterator f, InputIterator l);
       </pre>
    <p>are called with a type InputIterator that does not qualify as
    an input iterator, then these functions will behave as if the
    overloaded member functions:</p>
       <pre>       rt fx1(iterator, size_type, const value_type&amp;);

       rt fx2(size_type, const value_type&amp;);

       rt fx3(iterator, iterator, size_type, const value_type&amp;);
       </pre>
    <p>were called instead, with the same arguments.</p>
  </li>
</ul>

<p>In the previous paragraph the alternative binding will fail if f 
is not implicitly convertible to X::size_type or if l is not implicitly 
convertible to X::value_type.</p>

<p>
The extent to which an implementation determines that a type cannot be
an input iterator is unspecified, except that as a minimum integral
types shall not qualify as input iterators.
</p>



<p><i>[
Kona: agreed that the current standard requires <tt>v('a', 'b')</tt>
to be accepted, and also agreed that this is surprising behavior.  The
LWG considered several options, including something like
implicit_cast, which doesn't appear to be quite what we want.  We
considered Howards three options: allow acceptance or rejection,
require rejection as a compile time error, and require acceptance.  By
straw poll (1-6-1), we chose to require a compile time error.
Post-Kona: Howard provided wording.
]</i></p>

<p><i>[
Sydney: The LWG agreed with this general direction, but there was some
discomfort with the wording in the original proposed resolution.
Howard submitted new wording, and we will review this again in
Redmond.
]</i></p>

<p><i>[Redmond: one very small change in wording: the first argument
  is cast to size_t.  This fixes the problem of something like
  <tt>vector&lt;vector&lt;int&gt; &gt;(5, 5)</tt>, where int is not 
  implicitly convertible to the value type.]</i></p>

<p><b>Rationale:</b></p>
<p>The proposed resolution fixes:</p>

<pre>  vector&lt;int&gt; v(10, 1);
</pre>

<p>
since as integral types 10 and 1 must be disqualified as input
iterators and therefore the (size,value) constructor is called (as
if).</p>

<p>The proposed resolution breaks:</p>

<pre>  vector&lt;vector&lt;T&gt; &gt; v(10, 1);
</pre>

<p>
because the integral type 1 is not *implicitly* convertible to
vector&lt;T&gt;.  The wording above requires a diagnostic.</p>

<p>
The proposed resolution leaves the behavior of the following code
unspecified.
</p>

<pre>  struct A
  {
    operator int () const {return 10;}
  };

  struct B
  {
    B(A) {}
  };

  vector&lt;B&gt; v(A(), A());
</pre>

<p>
The implementation may or may not detect that A is not an input
iterator and employee the (size,value) constructor.  Note though that
in the above example if the B(A) constructor is qualified explicit,
then the implementation must reject the constructor as A is no longer
implicitly convertible to B.
</p>
<hr>
<a name="441"><h3>441.&nbsp;Is fpos::state const?</h3></a><p><b>Section:</b>&nbsp;27.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos"> [lib.fpos]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Vincent Leloup&nbsp; <b>Date:</b>&nbsp;17 Nov 2003</p>
<p>
In section 27.4.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos.members"> [lib.fpos.members]</a> fpos&lt;stateT&gt;::state() is declared
non const, but in section 27.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos"> [lib.fpos]</a> it is declared const.
</p>
<p><b>Proposed resolution:</b></p>
<p>
In section 27.4.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fpos.members"> [lib.fpos.members]</a>, change the declaration of 
<tt>fpos&lt;stateT&gt;::state()</tt> to const.
</p>
<hr>
<a name="442"><h3>442.&nbsp;sentry::operator bool() inconsistent signature</h3></a><p><b>Section:</b>&nbsp;27.6.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream::sentry"> [lib.ostream::sentry]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Vincent Leloup&nbsp; <b>Date:</b>&nbsp;18 Nov 2003</p>
<p>
In section 27.6.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream::sentry"> [lib.ostream::sentry]</a> paragraph 4, in description part
basic_ostream&lt;charT, traits&gt;::sentry::operator bool() is declared
as non const, but in section 27.6.2.3, in synopsis it is declared
const.
</p>
<p><b>Proposed resolution:</b></p>
<p>
In section 27.6.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream::sentry"> [lib.ostream::sentry]</a> paragraph 4, change the declaration
of <tt>sentry::operator bool()</tt> to const.
</p>
<hr>
<a name="443"><h3>443.&nbsp;filebuf::close() inconsistent use of EOF</h3></a><p><b>Section:</b>&nbsp;27.8.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.members"> [lib.filebuf.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Vincent Leloup&nbsp; <b>Date:</b>&nbsp;20 Nov 2003</p>
<p>
In section 27.8.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.filebuf.members"> [lib.filebuf.members]</a> par6, in effects description of
basic_filebuf&lt;charT, traits&gt;::close(), overflow(EOF) is used twice;
should be overflow(traits::eof()).
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change overflow(EOF) to overflow(traits::eof()).
</p>
<hr>
<a name="444"><h3>444.&nbsp;Bad use of casts in fstream</h3></a><p><b>Section:</b>&nbsp;27.8.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstreams"> [lib.fstreams]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Vincent Leloup&nbsp; <b>Date:</b>&nbsp;20 Nov 2003</p>
<p>
27.8.1.7 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ifstream.members"> [lib.ifstream.members]</a> p1, 27.8.1.10 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ofstream.members"> [lib.ofstream.members]</a> p1, 27.8.1.13 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstream.members"> [lib.fstream.members]</a> p1 seems have same problem as exposed in LWG issue
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#252">252</a>.
</p>
<p><b>Proposed resolution:</b></p>

<p><i>[Sydney: Genuine defect. 27.8.1.13 needs a cast to cast away
 constness. The other two places are stylistic: we could change the
 C-style casts to const_cast. Post-Sydney: Howard provided wording.
]</i></p>

<p>Change 27.8.1.7/1 from:</p>
<blockquote>
  Returns: (basic_filebuf&lt;charT,traits&gt;*)&amp;sb.
</blockquote>

<p>to:</p>
<blockquote>
  Returns: const_cast&lt;basic_filebuf&lt;charT,traits&gt;*&gt;(&amp;sb).
</blockquote>

<p>Change 27.8.1.10/1 from:</p>
<blockquote>
  Returns: (basic_filebuf&lt;charT,traits&gt;*)&amp;sb.
</blockquote>

<p>to:</p>
<blockquote>
  Returns: const_cast&lt;basic_filebuf&lt;charT,traits&gt;*&gt;(&amp;sb).
</blockquote>

<p>Change 27.8.1.13/1 from:</p>
<blockquote>
  Returns: &amp;sb.
</blockquote>

<p>to:</p>
<blockquote>
  Returns: const_cast&lt;basic_filebuf&lt;charT,traits&gt;*&gt;(&amp;sb).
</blockquote>



<hr>
<a name="445"><h3>445.&nbsp;iterator_traits::reference unspecified for some iterator categories</h3></a><p><b>Section:</b>&nbsp;24.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.traits"> [lib.iterator.traits]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;9 Dec 2003</p>
<p>
The standard places no restrictions at all on the reference type
of input, output, or forward iterators (for forward iterators it
only specifies that *x must be value_type&amp; and doesn't mention
the reference type).  Bidirectional iterators' reference type is
restricted only by implication, since the base iterator's
reference type is used as the return type of reverse_iterator's
operator*, which must be T&amp; in order to be a conforming forward
iterator.
</p>

<p>
Here's what I think we ought to be able to expect from an input
or forward iterator's reference type R, where a is an iterator
and V is its value_type
</p>

<ul>
  <li>
      *a is convertible to R
  </li>

  <li>
      R is convertible to V
  </li>

  <li>
      static_cast&lt;V&gt;(static_cast&lt;R&gt;(*a)) is equivalent to
      static_cast&lt;V&gt;(*a) 
  </li>
</ul>

<p>A mutable forward iterator ought to satisfy, for x of type V:</p>
  <li>
      { R r = *a; r = x; } is equivalent to *a = x;
  </li>

<p>
I think these requirements capture existing container iterators
(including vector&lt;bool&gt;'s), but render istream_iterator invalid;
its reference type would have to be changed to a constant
reference.
</p>


<p>
(Jeremy Siek) During the discussion in Sydney, it was felt that a
simpler long term solution for this was needed. The solution proposed
was to require <tt>reference</tt> to be the same type as <tt>*a</tt>
and <tt>pointer</tt> to be the same type as <tt>a-&gt;</tt>.  Most
iterators in the Standard Library already meet this requirement. Some
iterators are output iterators, and do not need to meet the
requirement, and others are only specified through the general
iterator requirements (which will change with this resolution). The
sole case where there is an explicit definition of the reference type
that will need to change is <tt>istreambuf_iterator</tt> which returns
<tt>charT</tt> from <tt>operator*</tt> but has a reference type of
<tt>charT&amp;</tt>. We propose changing the reference type of
<tt>istreambuf_iterator</tt> to <tt>charT</tt>.
</p>

<p>The other option for resolving the issue with <tt>pointer</tt>,
  mentioned in the note below, is to remove <tt>pointer</tt>
  altogether. I prefer placing requirements on <tt>pointer</tt> to
  removing it for two reasons. First, <tt>pointer</tt> will become
  useful for implementing iterator adaptors and in particular,
  <tt>reverse_iterator</tt> will become more well defined. Second,
  removing <tt>pointer</tt> is a rather drastic and publicly-visible
  action to take.</p>

<p>The proposed resolution technically enlarges the requirements for
iterators, which means there are existing iterators (such as
<tt>istreambuf_iterator</tt>, and potentially some programmer-defined
iterators) that will no longer meet the requirements. Will this break
existing code? The scenario in which it would is if an algorithm
implementation (say in the Standard Library) is changed to rely on
<tt>iterator_traits::reference</tt>, and then is used with one of the
iterators that do not have an appropriately defined
<tt>iterator_traits::reference</tt>.
</p>


<p>The proposed resolution makes one other subtle change. Previously,
it was required that output iterators have a <tt>difference_type</tt>
and <tt>value_type</tt> of <tt>void</tt>, which means that a forward
iterator could not be an output iterator. This is clearly a mistake,
so I've changed the wording to say that those types may be
<tt>void</tt>.
</p>

<p><b>Proposed resolution:</b></p>

<p>In 24.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.traits"> [lib.iterator.traits]</a>, after:</p>

<blockquote>
be defined as the iterator's difference type, value type and iterator
category, respectively.
</blockquote>

<p>add</p>

<blockquote>
In addition, the types
<pre>iterator_traits&lt;Iterator&gt;::reference
iterator_traits&lt;Iterator&gt;::pointer
</pre>
must be defined as the iterator's reference and pointer types, that
is, the same type as the type of <tt>*a</tt> and <tt>a-&gt;</tt>,
respectively.
</blockquote>

<p>In 24.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.iterator.traits"> [lib.iterator.traits]</a>, change:</p>

<blockquote>
In the case of an output iterator, the types
<pre>iterator_traits&lt;Iterator&gt;::difference_type
iterator_traits&lt;Iterator&gt;::value_type
</pre>
are both defined as <tt>void</tt>.
</blockquote>

<p>to:</p>
<blockquote>
In the case of an output iterator, the types
<pre>iterator_traits&lt;Iterator&gt;::difference_type
iterator_traits&lt;Iterator&gt;::value_type
iterator_traits&lt;Iterator&gt;::reference
iterator_traits&lt;Iterator&gt;::pointer
</pre>
may be defined as <tt>void</tt>.
</blockquote>

<p>In 24.5.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.istreambuf.iterator"> [lib.istreambuf.iterator]</a>, change:</p>
<blockquote>
<pre>typename traits::off_type, charT*, charT&amp;&gt;
</pre>
</blockquote>
<p>to:</p>
<blockquote>
<pre>typename traits::off_type, charT*, charT&gt;
</pre>
</blockquote>

<p><i>[
Redmond: there was concern in Sydney that this might not be the only place
where things were underspecified and needed to be changed.  Jeremy
reviewed iterators in the standard and confirmed that nothing else
needed to be changed.
]</i></p>

<hr>
<a name="448"><h3>448.&nbsp;Random Access Iterators over abstract classes</h3></a><p><b>Section:</b>&nbsp;24.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.random.access.iterators"> [lib.random.access.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;7 Jan 2004</p>
<p>
Table 76, the random access iterator requirement table, says that the
return type of a[n] must be "convertible to T".  When an iterator's
value_type T is an abstract class, nothing is convertible to T.
Surely this isn't an intended restriction?
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change the return type to "convertible to T const&amp;".
</p>
<hr>
<a name="449"><h3>449.&nbsp;Library Issue 306 Goes Too Far</h3></a><p><b>Section:</b>&nbsp;18.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.support.types"> [lib.support.types]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Pete Becker&nbsp; <b>Date:</b>&nbsp;15 Jan 2004</p>
<p>Original text:</p>
<blockquote>
The macro offsetof accepts a restricted set of type arguments in this
International Standard. type shall be a POD structure or a POD union
(clause 9). The result of applying the offsetof macro to a field that
is a static data member or a function member is undefined."
</blockquote>

<p>Revised text:</p>
<blockquote>
"If type is not a POD structure or a POD union the results are undefined."
</blockquote>

<p>
Looks to me like the revised text should have replaced only the second
sentence. It doesn't make sense standing alone.
</p>

<p><b>Proposed resolution:</b></p>
<p>Change 18.1, paragraph 5, to:</p>

<blockquote>
The macro offsetof accepts a restricted set of type arguments in this
International Standard.  If type is not a POD structure or a POD union
the results are undefined.  The result of applying the offsetof macro
to a field that is a static data member or a function member is
undefined."
</blockquote>
<hr>
<a name="453"></a><h3><a name="453">453.&nbsp;basic_stringbuf::seekoff need not always fail for an empty stream</a></h3><p><b>Section:</b>&nbsp;27.7.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.stringbuf.virtuals"> [lib.stringbuf.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Bill Plauger&nbsp; <b>Date:</b>&nbsp;30 Jan 2004</p>
<pre>  pos_type basic_stringbuf::seekoff(off_type, ios_base::seekdir,
                                    ios_base::openmode);
</pre>
<p>
is obliged to fail if nothing has been inserted into the stream. This
is unnecessary and undesirable. It should be permissible to seek to
an effective offset of zero.</p>

<p><i>[
 Sydney: Agreed that this is an annoying problem: seeking to zero should be
 legal. Bill will provide wording.
]</i></p>

<p><b>Proposed resolution:</b></p>
<p>Change the sentence from:</p>
<blockquote>
For a sequence to be positioned, if its next pointer (either
gptr() or pptr()) is a null pointer, the positioning operation
fails.
</blockquote>

<p>to:</p>

<blockquote>
For a sequence to be positioned, if its next pointer (either
gptr() or pptr()) is a null pointer and the new offset newoff
is nonzero, the positioning operation fails.
</blockquote>
<hr>
<a name="455"><h3>455.&nbsp;cerr::tie() and wcerr::tie() are overspecified</h3></a><p><b>Section:</b>&nbsp;27.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostream.objects"> [lib.iostream.objects]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Bill Plauger&nbsp; <b>Date:</b>&nbsp;30 Jan 2004</p>
<p>
Both cerr::tie() and wcerr::tie() are obliged to be null at program
startup. This is overspecification and overkill. It is both traditional
and useful to tie cerr to cout, to ensure that standard output is drained
whenever an error message is written. This behavior should at least be
permitted if not required. Same for wcerr::tie().
</p>
<p><b>Proposed resolution:</b></p>

<p>Add to the description of cerr:</p>
<blockquote>
After the object cerr is initialized, cerr.tie() returns &amp;cout.
Its state is otherwise the same as required for basic_ios&lt;char&gt;::init
(lib.basic.ios.cons).
</blockquote>

<p>Add to the description of wcerr:</p>

<blockquote>
After the object wcerr is initialized, wcerr.tie() returns &amp;wcout.
Its state is otherwise the same as required for basic_ios&lt;wchar_t&gt;::init
(lib.basic.ios.cons).
</blockquote>

<p><i>[Sydney: straw poll (3-1): we should <i>require</i>, not just
  permit, cout and cerr to be tied on startup.  Pre-Redmond: Bill will
  provide wording.]</i></p>
<hr>
<a name="457"><h3>457.&nbsp;bitset constructor: incorrect number of initialized bits</h3></a><p><b>Section:</b>&nbsp;23.3.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.cons"> [lib.bitset.cons]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Dag Henriksson&nbsp; <b>Date:</b>&nbsp;30 Jan 2004</p>
<p>
The constructor from unsigned long says it initializes "the first M
bit positions to the corresponding bit values in val. M is the smaller
of N and the value CHAR_BIT * sizeof(unsigned long)."
</p>

<p>
Object-representation vs. value-representation strikes again. CHAR_BIT *
sizeof (unsigned long) does not give us the number of bits an unsigned long
uses to hold the value. Thus, the first M bit position above is not
guaranteed to have any corresponding bit values in val.
</p>
<p><b>Proposed resolution:</b></p>
<p>In 23.3.5.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.bitset.cons"> [lib.bitset.cons]</a> paragraph 2, change "M is the smaller of
  N and the value CHAR_BIT * sizeof (unsigned long). (249)" to
  "<tt>M</tt> is the smaller of <tt>N</tt> and the number of bits in
  the value representation (section 3.9 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/basic.html#basic.types"> [basic.types]</a>) of <tt>unsigned
  long</tt>."
</p>
<hr>
<a name="460"><h3>460.&nbsp;Default modes missing from basic_fstream member specifications</h3></a><p><b>Section:</b>&nbsp;27.8.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstreams"> [lib.fstreams]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Ben Hutchings&nbsp; <b>Date:</b>&nbsp;1 Apr 2004</p>
<p>
The second parameters of the non-default constructor and of the open
member function for basic_fstream, named "mode", are optional
according to the class declaration in 27.8.1.11 [lib.fstream].  The
specifications of these members in 27.8.1.12 [lib.fstream.cons] and
27.8.1.13 lib.fstream.members] disagree with this, though the
constructor declaration has the "explicit" function-specifier implying
that it is intended to be callable with one argument.
</p>
<p><b>Proposed resolution:</b></p>
<p>In 27.8.1.12 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstream.cons"> [lib.fstream.cons]</a>, change</p>
<pre>  explicit basic_fstream(const char* s, ios_base::openmode mode); 
</pre>
<p>to</p>
<pre>  explicit basic_fstream(const char* s,
                         ios_base::openmode mode = ios_base::in|ios_base::out);
</pre>
<p>In 27.8.1.13 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.fstream.members"> [lib.fstream.members]</a>, change</p>
<pre>  void open(const char*s, ios_base::openmode mode); 
</pre>
<p>to</p>
  void open(const char*s,
            ios_base::openmode mode = ios_base::in|ios_base::out);
<hr>
<a name="461"><h3>461.&nbsp;time_get hard or impossible to implement</h3></a><p><b>Section:</b>&nbsp;22.2.5.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.locale.time.get.virtuals"> [lib.locale.time.get.virtuals]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Bill Plauger&nbsp; <b>Date:</b>&nbsp;23 Mar 2004</p>
<p>
Template time_get currently contains difficult, if not impossible,
requirements for do_date_order, do_get_time, and do_get_date. All require
the implementation to scan a field generated by the %x or %X conversion
specifier in strftime. Yes, do_date_order can always return no_order, but
that doesn't help the other functions. The problem is that %x can be
nearly anything, and it can vary widely with locales. It's horribly
onerous to have to parse "third sunday after Michaelmas in the year of
our Lord two thousand and three," but that's what we currently ask of
do_get_date. More practically, it leads some people to think that if
%x produces 10.2.04, we should know to look for dots as separators. Still
not easy.
</p>

<p>
Note that this is the <i>opposite</i> effect from the intent stated in the
footnote earlier in this subclause:
</p>

<blockquote>
"In other words, user confirmation is required for reliable parsing of
user-entered dates and times, but machine-generated formats can be
parsed reliably. This allows parsers to be aggressive about interpreting
user variations on standard formats."
</blockquote>

<p>
We should give both implementers and users an easier and more reliable
alternative: provide a (short) list of alternative delimiters and say
what the default date order is for no_order. For backward compatibility,
and maximum latitude, we can permit an implementation to parse whatever
%x or %X generates, but we shouldn't require it.
</p>
<p><b>Proposed resolution:</b></p>

<p><b>In the description:</b></p>
<pre>iter_type do_get_time(iter_type s, iter_type end, ios_base&amp; str,
        ios_base::iostate&amp; err, tm* t) const;
</pre>

<p>
2 Effects: Reads characters starting at suntil it has extracted those
struct tm members, and remaining format characters, used by
time_put&lt;&gt;::put to produce the format specified by 'X', or until it
encounters an error or end of sequence.
</p>

<p><b>change:</b> 'X'</p>

<p><b>to:</b> "%H:%M:%S"</p>


<p>Change</p>
<pre>iter_type do_get_date(iter_type s, iter_type end, ios_base&amp; str,
        ios_base::iostate&amp; err, tm* t) const;

4 Effects: Reads characters starting at s until it has extracted those
struct tm members, and remaining format characters, used by
time_put&lt;&gt;::put to produce the format specified by 'x', or until it
encounters an error.
</pre>

<p>to</p>
iter_type do_get_date(iter_type s, iter_type end, ios_base&amp; str,
        ios_base::iostate&amp; err, tm* t) const;

4 Effects: Reads characters starting at s until it has extracted those
struct tm members, and remaining format characters, used by
time_put&lt;&gt;::put to produce one of the following formats, or until it
encounters an error. The format depends on the value returned by
date_order() as follows:

        date_order()  format

        no_order      "%m/%d/%y"
        dmy           "%d/%m/%y"
        mdy           "%m/%d/%y"
        ymd           "%y/%m/%d"
        ydm           "%y/%d/%m"

An implementation may also accept additional implementation-defined formats.
<pre></pre>

<p><i>[Redmond: agreed that this is a real problem.  The solution is
  probably to match C99's parsing rules.  Bill provided wording.
]</i></p>

<hr>
<a name="464"><h3>464.&nbsp;Suggestion for new member functions in standard containers</h3></a><p><b>Section:</b>&nbsp;23.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.adaptors"> [lib.container.adaptors]</a>, 23.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map"> [lib.map]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Thorsten Ottosen&nbsp; <b>Date:</b>&nbsp;12 May 2004</p>

<p>To add slightly more convenience to vector&lt;T&gt; and map&lt;Key,T&gt; we should consider to add</p>
<ol>
<li> add vector&lt;T&gt;::data() member (const and non-const version)
semantics: if( empty() ) return 0; else return buffer_;</li>
<li> add map&lt;Key,T&gt;::at( const Key&amp; k ) member (const and non-const version)
<i>semantics</i>: iterator i = find( k ); if( i != end() ) return *i; else throw range_error();</li>
</ol>

<p>Rationale:</p>

<ul>
<li>To obtain a pointer to the vector's buffer, one must use either
operator[]() (which can give undefined behavior for empty vectors) or
at() (which will then throw if the vector is empty). </li>
<li>tr1::array&lt;T,sz&gt; already has a data() member</li>
<li>e cannot use operator[]() when T is not DefaultDonstructible</li>
<li>Neither when the map is const.</li>
<li>when we want to make sure we don't add an element accidently</li>
<li>when it should be considered an error if a key is not in the map</li>
</ul>

<p><b>Proposed resolution:</b></p>
<p>In 23.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.adaptors"> [lib.container.adaptors]</a>, add the following to the <tt>vector</tt>
  synopsis after "element access" and before "modifiers":</p>
<pre>  // <i>[lib.vector.data] data access</i>
  pointer       data();
  const_pointer data() const;
</pre>

<p>Add a new subsection of 23.2.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.container.adaptors"> [lib.container.adaptors]</a>:</p>
<blockquote>
<p>23.2.4.x <tt>vector</tt> data access</p>
<pre>   pointer       data();
   const_pointer data() const;
</pre>
<p><b>Returns:</b> A pointer such that [data(), data() + size()) is a valid
   range.  For a non-empty vector, data() == &amp;front().</p>
<p><b>Complexity:</b> Constant time.</p>
<p><b>Throws:</b> Nothing.</p>
</blockquote>

<p>In 23.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map"> [lib.map]</a>, add the following to the <tt>map</tt>
synopsis immediately after the line for operator[]:</p>
<pre>  T&amp;       at(const key_type&amp; x);
  const T&amp; at(const key_type&amp; x) const;
</pre>

<p>Add the following to 23.3.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.map.access"> [lib.map.access]</a>:</p>
<blockquote>
<pre>  T&amp;       at(const key_type&amp; x);
  const T&amp; at(const key_type&amp; x) const;
</pre>

<p><b>Returns:</b> A reference to the element whose key is equivalent
  to x, if such an element is present in the map.</p>
<p><b>Throws:</b> <tt>out_of_range</tt> if no such element is present.</p>

</blockquote>

<p><b>Rationale:</b></p>
<p>Neither of these additions provides any new functionality but the
  LWG agreed that they are convenient, especially for novices.  The
  exception type chosen for <tt>at</tt>, <tt>std::out_of_range</tt>,
  was chosen to match <tt>vector::at</tt>.</p>
<hr>
<a name="465"><h3>465.&nbsp;Contents of &lt;ciso646&gt;</h3></a><p><b>Section:</b>&nbsp;17.4.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.headers"> [lib.headers]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Steve Clamage&nbsp; <b>Date:</b>&nbsp;3 Jun 2004</p>
<p>C header &lt;iso646.h&gt; defines macros for some operators, such as
not_eq for !=.</p>

<p>Section 17.4.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.headers"> [lib.headers]</a> "Headers" says that except as noted in
clauses 18 through 27, the &lt;cname&gt; C++ header contents are the same
as the C header &lt;name.h&gt;. In particular, table 12 lists
&lt;ciso646&gt; as a C++ header.</p>

<p>I don't find any other mention of &lt;ciso646&gt;, or any mention of
&lt;iso646.h&gt;, in clauses 17 thorough 27. That implies that the
contents of &lt;ciso646&gt; are the same as C header &lt;iso646.h&gt;.</p>

<p>Annex C (informative, not normative) in [diff.header.iso646.h] C.2.2.2
"Header &lt;iso646.h&gt;" says that the alternative tokens are not
defined as macros in &lt;ciso646&gt;, but does not mention the contents
of &lt;iso646.h&gt;.</p>

<p>I don't find any normative text to support C.2.2.2.</p>

<p><b>Proposed resolution:</b></p>
<p>Add to section 17.4.1.2 Headers [lib.headers] a new paragraph after
  paragraph 6 (the one about functions must be functions):</p> 

<blockquote>
<p>Identifiers that are keywords or operators in C++ shall not be defined
as macros in C++ standard library headers. 
[Footnote:In particular, including the standard header &lt;iso646.h&gt;
or &lt;ciso646&gt; has no effect. </p>
</blockquote>

<p><i>[post-Redmond: Steve provided wording.]</i></p>

<hr>
<a name="467"><h3>467.&nbsp;char_traits::lt(), compare(), and memcmp()</h3></a><p><b>Section:</b>&nbsp;21.1.3.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.char.traits.specializations.char"> [lib.char.traits.specializations.char]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;28 Jun 2004</p>

<p>
Table 37 describes the requirements on Traits::compare() in terms of
those on Traits::lt(). 21.1.3.1, p6 requires char_traits&lt;char&gt;::lt()
to yield the same result as operator&lt;(char, char).
</p>

<p>
Most, if not all, implementations of char_traits&lt;char&gt;::compare()
call memcmp() for efficiency. However, the C standard requires both
memcmp() and strcmp() to interpret characters under comparison as
unsigned, regardless of the signedness of char. As a result, all
these char_traits implementations fail to meet the requirement
imposed by Table 37 on compare() when char is signed.
</p>


<p>Read email thread starting with c++std-lib-13499 for more. </p>
<p><b>Proposed resolution:</b></p>


<p>Change 21.1.3.1, p6 from</p>
<blockquote>
    The two-argument members assign, eq, and lt are defined identically
    to the built-in operators =, ==, and &lt; respectively.
</blockquote>
<p>to</p>
<blockquote>
  The two-argument member assign is defined identically to
  the built-in operator =. The two
  argument members eq and lt are defined identically to
  the built-in operators == and &lt; for type unsigned char.
</blockquote>

<p><i>[Redmond: The LWG agreed with this general direction, but we
  also need to change <tt>eq</tt> to be consistent with this change.
  Post-Redmond: Martin provided wording.]</i></p>

<hr>
<a name="468"><h3>468.&nbsp;unexpected consequences of ios_base::operator void*()</h3></a><p><b>Section:</b>&nbsp;27.4.4.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.iostate.flags"> [lib.iostate.flags]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;28 Jun 2004</p>

<p>The program below is required to compile but when run it typically
produces unexpected results due to the user-defined conversion from
std::cout or any object derived from basic_ios to void*.
</p>

<pre>    #include &lt;cassert&gt;
    #include &lt;iostream&gt;

    int main ()
    {
        assert (std::cin.tie () == std::cout);
        // calls std::cout.ios::operator void*()
    }
</pre>

<p><b>Proposed resolution:</b></p>

<p>
Replace std::basic_ios&lt;charT, traits&gt;::operator void*() with another
conversion operator to some unspecified type that is guaranteed not
to be convertible to any other type except for bool (a pointer-to-member
might be one such suitable type). In addition, make it clear that the
pointer type need not be a pointer to a complete type and when non-null,
the value need not be valid.
</p>

<p>Specifically, change in [lib.ios] the signature of</p>
<pre>    operator void*() const;
</pre>
<p>to</p>
<pre>    operator unspecified-bool-type() const;
</pre>
<p>and change [lib.iostate.flags], p1 from</p>
<pre>    operator void*() const;
</pre>
<p>to</p>
<pre>operator unspecified-bool-type() const;

     -1- Returns: if fail() then a value that will evaluate false in a
      boolean context; otherwise a value that will evaluate true in a
      boolean context. The value type returned shall not be
      convertible to int.

     -2- [Note: This conversion can be used in contexts where a bool
      is expected (e.g., an if condition); however, implicit
      conversions (e.g., to int) that can occur with bool are not
      allowed, eliminating some sources of user error. One possible
      implementation choice for this type is pointer-to-member.  - end
      note]
</pre>

<p><i>[Redmond: 5-4 straw poll in favor of doing this.]</i></p>
<p><i>[Lillehammer: Doug provided revised wording for
  "unspecified-bool-type".]</i></p> 

<hr>
<a name="469"><h3>469.&nbsp;vector&lt;bool&gt; ill-formed relational operators</h3></a><p><b>Section:</b>&nbsp;23.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.vector"> [lib.vector]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;28 Jun 2004</p>

<p>
The overloads of relational operators for vector&lt;bool&gt; specified
in [lib.vector.bool] are redundant (they are semantically identical
to those provided for the vector primary template) and may even be
diagnosed as ill-formed (refer to Daveed Vandevoorde's explanation
in c++std-lib-13647).
</p>

<p><b>Proposed resolution:</b></p>
<p>
Remove all overloads of overloads of relational operators for
vector&lt;bool&gt; from [lib.vector.bool].
</p>
<hr>
<a name="474"><h3>474.&nbsp;confusing Footnote 297</h3></a><p><b>Section:</b>&nbsp;27.6.2.5.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.ostream.inserters.character"> [lib.ostream.inserters.character]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;1 Jul 2004</p>

<p>
I think Footnote 297 is confused. The paragraph it applies to seems
quite clear in that widen() is only called if the object is not a char
stream (i.e., not basic_ostream&lt;char&gt;), so it's irrelevant what the
value of widen(c) is otherwise.
</p>
<p><b>Proposed resolution:</b></p>
<p>
I propose to strike the Footnote.
</p>
<hr>
<a name="475"><h3>475.&nbsp;May the function object passed to for_each modify the elements of the iterated sequence?</h3></a><p><b>Section:</b>&nbsp;25.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.foreach"> [lib.alg.foreach]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Stephan T. Lavavej, Jaakko Jarvi&nbsp; <b>Date:</b>&nbsp;9 Jul 2004</p>
<p>
It is not clear whether the function object passed to for_each is allowed to
modify the elements of the sequence being iterated over.
</p>

<p>
for_each is classified without explanation in [lib.alg.nonmodifying], "25.1
Non-modifying sequence operations". 'Non-modifying sequence operation' is
never defined.
</p>

<p>
25(5) says: "If an algorithm's Effects section says that a value pointed to
by any iterator passed as an argument is modified, then that algorithm has
an additional type requirement: The type of that argument shall satisfy the
requirements of a mutable iterator (24.1)."
</p>

<p>for_each's Effects section does not mention whether arguments can be
modified:</p>

<blockquote>
  "Effects: Applies f to the result of dereferencing every iterator in the
   range [first, last), starting from first and proceeding to last - 1."
</blockquote>

<p>
Every other algorithm in [lib.alg.nonmodifying] is "really" non-modifying in
the sense that neither the algorithms themselves nor the function objects
passed to the algorithms may modify the sequences or elements in any way.
This DR affects only for_each.
</p>

<p>
We suspect that for_each's classification in "non-modifying sequence
operations" means that the algorithm itself does not inherently modify the
sequence or the elements in the sequence, but that the function object
passed to it may modify the elements it operates on. 
</p>

<p>
The original STL document by Stepanov and Lee explicitly prohibited the
function object from modifying its argument.
The "obvious" implementation of for_each found in several standard library 
implementations, however, does not impose this restriction.
As a result, we suspect that the use of for_each with function objects that modify
their arguments is wide-spread. 
If the restriction was reinstated, all such code would become non-conforming.
Further, none of the other algorithms in the Standard
could serve the purpose of for_each (transform does not guarantee the order in
which its function object is called). 
</p>

<p>
We suggest that the standard be clarified to explicitly allow the function object 
passed to for_each modify its argument.</p>

<p><b>Proposed resolution:</b></p>
<p>Add a nonnormative note to the Effects in 25.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.foreach"> [lib.alg.foreach]</a>: If
the type of 'first' satisfies the requirements of a mutable iterator,
'f' may apply nonconstant functions through the dereferenced iterators
passed to it.
</p>

<p><b>Rationale:</b></p>
<p>The LWG believes that nothing in the standard prohibits function
  objects that modify the sequence elements. The problem is that
  for_each is in a secion entitled "nonmutating algorithms", and the
  title may be confusing.  A nonnormative note should clarify that.</p>
<hr>
<a name="478"><h3>478.&nbsp;Should forward iterator requirements table have a line for r-&gt;m?</h3></a><p><b>Section:</b>&nbsp;24.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iterators.html#lib.forward.iterators"> [lib.forward.iterators]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Dave Abrahams&nbsp; <b>Date:</b>&nbsp;11 Jul 2004</p>
<p>
The Forward Iterator requirements table contains the following:
</p>
<pre> expression  return type         operational  precondition
                                  semantics
  ==========  ==================  ===========  ==========================
  a-&gt;m        U&amp; if X is mutable, (*a).m       pre: (*a).m is well-defined.
              otherwise const U&amp;

  r-&gt;m        U&amp;                  (*r).m       pre: (*r).m is well-defined.
</pre>

<p>The second line may be unnecessary.  Paragraph 11 of
  [lib.iterator.requirements] says:
</p>

<blockquote>
   In the following sections, a and b denote values of type const X, n
   denotes a value of the difference type Distance, u, tmp, and m
   denote identifiers, r denotes a value of X&amp;, t denotes a value of
   value type T, o denotes a value of some type that is writable to
   the output iterator.
</blockquote>

<p>
Because operators can be overloaded on an iterator's const-ness, the
current requirements allow iterators to make many of the operations
specified using the identifiers a and b invalid for non-const
iterators.</p>

<p>Related issue: <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-closed.html#477">477</a></p>
<p><b>Proposed resolution:</b></p>

<p>Remove the "r-&gt;m" line from the Forward Iterator requirements
table. Change</p>
<blockquote>
    "const X"
</blockquote>

<p> to </p>

<blockquote>
    "X or const X" 
</blockquote>

<p>in paragraph 11 of [lib.iterator.requirements].</p>


<p><b>Rationale:</b></p>
<p>
This is a defect because it constrains an lvalue to returning a modifiable lvalue.
</p>
<hr>
<a name="495"><h3>495.&nbsp;Clause 22 template parameter requirements</h3></a><p><b>Section:</b>&nbsp;22 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-locales.html#lib.localization"> [lib.localization]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;10 Jan 2005</p>
<p>It appears that there are no requirements specified for many of the
template parameters in clause 22. It looks like this issue has never
come up, except perhaps for Facet.</p>

<p>Clause 22 isn't even listed in 17.3.2.1 [lib.type.descriptions],
either, which is the wording that allows requirements on template
parameters to be identified by name.</p>

<p>So one issue is that 17.3.2.1 [lib.type.descriptions] Should be
changed to cover clause 22. A better change, which will cover us in
the future, would be to say that it applies to all the library
clauses. Then if a template gets added to any library clause we are
covered.</p>

<p>charT, InputIterator, and other names with requirements defined
elsewhere are fine, assuming the 17.3.2.1 [lib.type.descriptions] fix.
But there are a few template arguments names which I don't think have
requirements given elsewhere:</p>

<ul>
<li>internT and externT.  The fix is to add wording saying that internT
and externT must meet the same requirements as template arguments
named charT.</li>

<li>stateT.  I'm not sure about this one. There already is some wording,
but it seems a bit vague.</li>

<li>Intl.  [lib.locale.moneypunct.byname] The fix for this one is to
rename "Intl" to "International". The name is important because other
text identifies the requirements for the name International but not
for Intl.</li>
</ul>
<p><b>Proposed resolution:</b></p>
<p>Change 17.3.2.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-intro.html#lib.type.descriptions"> [lib.type.descriptions]</a>, paragraph 1, from:</p>
<blockquote>
The Requirements subclauses may describe names that are used to
specify constraints on template arguments.153) These names are used in
clauses 20, 23, 25, and 26 to describe the types that may be supplied
as arguments by a C++ program when instantiating template components
from the library. 
</blockquote>
<p>to:</p>
<blockquote>
The Requirements subclauses may describe names that are used to
specify constraints on template arguments.153) These names are used in
library clauses to describe the types that may be supplied as
arguments by a C++ program when instantiating template components from
the library.
</blockquote>

<p>In the front matter of class 22, locales, add:</p>
<blockquote>
Template parameter types internT and externT shall meet the
requirements of charT (described in 21 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.strings"> [lib.strings]</a>).
</blockquote>
<p><b>Rationale:</b></p>
<p>
 Again, a blanket clause isn't blanket enough. Also, we've got a
 couple of names that we don't have blanket requirement statements
 for. The only issue is what to do about stateT. This wording is
 thin, but probably adequate.</p>
<hr>
<a name="496"><h3>496.&nbsp;Illegal use of "T" in vector&lt;bool&gt;</h3></a><p><b>Section:</b>&nbsp;23.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.vector"> [lib.vector]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;richard@ex-parrot.com&nbsp; <b>Date:</b>&nbsp;10 Feb 2005</p>
<p>
In the synopsis of the std::vector&lt;bool&gt; specialisation in 23.2.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.vector"> [lib.vector]</a>,
the non-template assign() function has the signature</p>

<pre>  void assign( size_type n, const T&amp; t );
</pre>

<p>The type, T, is not defined in this context.</p>
<p><b>Proposed resolution:</b></p>
<p>Replace "T" with "value_type".</p>
<hr>
<a name="497"><h3>497.&nbsp;meaning of numeric_limits::traps for floating point types</h3></a><p><b>Section:</b>&nbsp;18.2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-support.html#lib.numeric.limits.members"> [lib.numeric.limits.members]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;2 Mar 2005</p>

<p>18.2.1.2, p59 says this much about the traps member of numeric_limits:</p>

<blockquote>
<p>static const bool traps;<br>
-59- true if trapping is implemented for the type.204)
<br>
Footnote 204: Required by LIA-1.
</p>
</blockquote>

<p>It's not clear what is meant by "is implemented" here.</p>

<p>
In the context of floating point numbers it seems reasonable to expect
to be able to use traps to determine whether a program can "safely" use
infinity(), quiet_NaN(), etc., in arithmetic expressions, that is
without causing a trap (i.e., on UNIX without having to worry about
getting a signal). When traps is true, I would expect any of the
operations in section 7 of IEEE 754 to cause a trap (and my program
to get a SIGFPE). So, for example, on Alpha, I would expect traps
to be true by default (unless I compiled my program with the -ieee
option), false by default on most other popular architectures,
including IA64, MIPS, PA-RISC, PPC, SPARC, and x86 which require
traps to be explicitly enabled by the program.
</p>

<p>
Another possible interpretation of p59 is that traps should be true
on any implementation that supports traps regardless of whether they
are enabled by default or not. I don't think such an interpretation
makes the traps member very useful, even though that is how traps is
implemented on several platforms. It is also the only way to implement
traps on platforms that allow programs to enable and disable trapping
at runtime.
</p>
<p><b>Proposed resolution:</b></p>
<p>Change p59 to read:</p>
<blockquote>True if, at program startup, there exists a value of the type that
  would cause an arithmetic operation using that value to trap.</blockquote>
<p><b>Rationale:</b></p>
<p>
 Real issue, since trapping can be turned on and off. Unclear what a
 static query can say about a dynamic issue. The real advice we should
 give users is to use cfenv for these sorts of queries. But this new
 proposed resolution is at least consistent and slightly better than
 nothing.</p>
<hr>
<a name="505"><h3>505.&nbsp;Result_type in random distribution requirements</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.1 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.req"> [tr.rand.req]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
<p>
Table 17: Random distribution requirements
</p>
<p>
Row 1 requires that each random distribution provide a nested type "input_type";
this type denotes the type of the values that the distribution consumes.
</p>
<p>
Inspection of all distributions in [tr.rand.dist] reveals that each distribution
provides a second typedef ("result_type") that denotes the type of the values the
distribution produces when called.  
</p>
<p><b>Proposed resolution:</b></p>
<p>
It seems to me that this is also a requirement
for all distributions and should therefore be  indicated as such via a new second
row to this table 17:
</p>
<table border="1" cellpadding="5">
<tbody><tr>
<td>X::result_type</td>
<td>T</td>
<td>---</td>
<td>compile-time</td>
</tr>
</tbody></table>

<p><i>[
Berlin:  Voted to WP.  N1932 adopts the proposed resolution:  see Table 5 row 1.
]</i></p>

<hr>
<a name="507"><h3>507.&nbsp;Missing requirement for variate_generator::operator()</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.var"> [tr.rand.var]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
<p>
Paragraph 11 of [tr.rand.var] equires that the member template
</p>
<blockquote><pre>template&lt;class T&gt; result_type operator() (T value);
</pre></blockquote>
<p>
return
</p>
<blockquote><pre>distribution()(e, value)
</pre></blockquote>
<p>
However, not all distributions have an operator() with a corresponding signature.
</p>

<p><i>[
Berlin:  As a working group we voted in favor of N1932 which makes this moot:
variate_generator has been eliminated.  Then in full committee we voted to give
this issue WP status (mistakenly).
]</i></p>

<p><b>Proposed resolution:</b></p>
<p>
We therefore  recommend that we insert the following precondition before paragraph 11:
</p>
<blockquote>
Precondition:  <tt>distribution().operator()(e,value)</tt> is well-formed.
</blockquote>
<hr>
<a name="508"><h3>508.&nbsp;Bad parameters for ranlux64_base_01</h3></a><p><b>Section:</b>&nbsp;TR1 5.1.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.rand.predef"> [tr.rand.predef]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Walter Brown&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
<p>
The fifth of these engines with predefined parameters, ranlux64_base_01,
appears to have an unintentional error for which there is a simple correction.
The two pre-defined  subtract_with_carry_01 engines are given as: 
</p>
<blockquote><pre>typedef subtract_with_carry_01&lt;float,  24, 10, 24&gt; ranlux_base_01;
typedef subtract_with_carry_01&lt;double, 48, 10, 24&gt; ranlux64_base_01;
</pre></blockquote>
<p>
We demonstrate below that ranlux64_base_01 fails to meet the intent of the
random number generation proposal, but that the simple correction to
</p>
<blockquote><pre>typedef subtract_with_carry_01&lt;double, 48,  5, 12&gt; ranlux64_base_01;
</pre></blockquote>
<p>
does meet the intent of defining well-known good parameterizations.
</p>
<p>
The ranlux64_base_01 engine as presented fails to meet the intent for
predefined engines, stated in proposal N1398 (section E):
</p>
<blockquote><p>
In order to make good random numbers available to a large number of library
users, this proposal not only defines generic random-number engines, but also
provides a number of predefined well-known good parameterizations for those.
</p></blockquote>
<p>
The predefined ranlux_base_01 engine has been proven [1,2,3] to have a very
long period and so meets this criterion.  This property makes it suitable for
use in the excellent discard_block  engines defined subsequently.  The proof
of long period relies on the fact (proven in [1]) that 2**(w*r) - 2**(w*s)
+ 1 is prime (w, r, and s are template parameters to subtract_with_carry_01,
as defined in [tr.rand.eng.sub1]).
</p>
<p>
The ranlux64_base_01 engine as presented in [tr.rand.predef] uses w=48, r=24, s=10.
For these numbers, the combination 2**(w*r)-2**(w*s)+1 is non-prime (though
explicit factorization  would be a challenge).  In consequence, while it is
certainly possible for some seeding states that this engine would have a very
long period, it is not at all Òwell-knownÓ that this is the case. The intent
in the N1398 proposal involved the base of the ranlux64 engine, which finds heavy
use in the physics community.  This is isomorphic to the predefined ranlux_base_01,
but exploits the ability of double variables to hold (at least) 48 bits of mantissa,
to deliver 48 random bits at a time rather than 24.
</p>
<p><b>Proposed resolution:</b></p>
<p>
To achieve this intended behavior, the correct template parameteriztion  would be:
</p>
<blockquote><pre>typedef subtract_with_carry_01&lt;double, 48, 5, 12&gt; ranlux64_base_01;
</pre></blockquote>
<p>
The sequence of mantissa bits delivered by this is isomorphic (treating each
double as having the  bits of two floats) to that delivered by ranlux_base_01.
</p>
<p>
<b>References:</b>
</p>
<ol>
<li>F. James, Comput. Phys. Commun. 60(1990) 329</li>
<li>G. Marsaglia and A. Zaman, Ann. Appl. Prob 1(1991) 462</li>
<li>M. Luscher, Comput. Phys. Commun. 79(1994) 100-110</li>
</ol>

<p><i>[
Berlin: Voted to WP.  N1932 adopts the proposed resolution in 26.3.5,
just above paragraph 5.
]</i></p>

<hr>
<a name="519"><h3>519.&nbsp;Data() undocumented</h3></a><p><b>Section:</b>&nbsp;TR1 6.2.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.array.array"> [tr.array.array]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Pete Becker&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
<p>
<tt>array&lt;&gt;::data()</tt> is present in the class synopsis, but not documented.
</p>
<p><b>Proposed resolution:</b></p>
<p>
Add a new section, after 6.2.2.3:
</p>
<blockquote><pre>T*       data()
const T* data() const;
</pre></blockquote>
<p>
<b>Returns:</b> <tt>elems</tt>.
</p>
<p>
Change 6.2.2.4/2 to:
</p>
<blockquote>
In the case where <tt>N == 0</tt>, <tt>begin() == end()</tt>. The return value
of <tt>data()</tt> is unspecified.
</blockquote>
<hr>
<a name="520"><h3>520.&nbsp;Result_of and pointers to data members</h3></a><p><b>Section:</b>&nbsp;TR1 3.6 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.func.bind"> [tr.func.bind]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Pete Becker&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
<p>
In the original proposal for binders, the return type of bind() when
called with a pointer to member data as it's callable object was
defined to be mem_fn(ptr); when Peter Dimov and I  unified the
descriptions of the TR1 function objects we hoisted the descriptions
of return types into the INVOKE pseudo-function and into result_of.
Unfortunately, we left pointer to member data out of result_of, so
bind doesn't have any specified behavior when called with a pointer
to  member data.
</p>
<p><b>Proposed resolution:</b></p>
<p><i>[
Pete and Peter will provide wording.
]</i></p>

<p>
In 20.5.4 [lib.func.ret] ([tr.func.ret]) p3 add the following bullet after bullet 2:
</p>
<ol start="3">
<li>If <tt>F</tt> is a member data pointer type <tt>R T::*</tt>, <tt>type</tt>
shall be <tt><i>cv</i> R&amp;</tt> when <tt>T1</tt> is <tt><i>cv</i> U1&amp;</tt>,
<tt>R</tt> otherwise.</li>
</ol>

<p><i>[
Peter provided wording.
]</i></p>
<hr>
<a name="521"><h3>521.&nbsp;Garbled requirements for argument_type in reference_wrapper</h3></a><p><b>Section:</b>&nbsp;TR1 2.1.2 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.util.refwrp.refwrp"> [tr.util.refwrp.refwrp]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Pete Becker&nbsp; <b>Date:</b>&nbsp;3 Jul 2005</p>
<p>
2.1.2/3, second bullet item currently says that reference_wrapper&lt;T&gt; is
derived from unary_function&lt;T, R&gt; if T is:
</p>
<blockquote>
a pointer to member function type with cv-qualifier cv and no arguments;
the type T1 is cv T* and R is the return type of the pointer to member function;
</blockquote>
<p>
The type of T1 can't be cv T*, 'cause that's a pointer to a pointer to member
function. It should be a pointer to the class that T is a pointer to member of.
Like this:
</p>
<blockquote>
a pointer to a member function R T0::f() cv (where cv represents the member
function's cv-qualifiers); the type T1 is cv T0*
</blockquote>
<p>
Similarly, bullet item 2 in 2.1.2/4 should be:
</p>
<blockquote>
a pointer to a member function R T0::f(T2) cv (where cv represents the member
function's cv-qualifiers); the type T1 is cv T0*
</blockquote>
<p><b>Proposed resolution:</b></p>

<p>
Change bullet item 2 in 2.1.2/3:
</p>

<blockquote>
<ul>
<li>
a pointer to member function <del>type with cv-qualifier <tt><i>cv</i></tt> and no arguments;
the type <tt>T1</tt> is <tt><i>cv</i> T*</tt> and <tt>R</tt> is the return 
type of the pointer to member function</del> <ins><tt>R T0::f() <i>cv</i></tt>
(where <tt><i>cv</i></tt> represents the member function's cv-qualifiers);
the type <tt>T1</tt> is <tt><i>cv</i> T0*</tt></ins>
</li>
</ul>
</blockquote>

<p>
Change bullet item 2 in 2.1.2/4:
</p>

<blockquote>
<ul>
<li>
a pointer to member function <del>with cv-qualifier <tt><i>cv</i></tt> and taking one argument
of type <tt>T2</tt>; the type <tt>T1</tt> is <tt><i>cv</i> T*</tt> and 
<tt>R</tt> is the return type of the pointer to member function</del>
<ins><tt>R T0::f(T2) <i>cv</i></tt> (where <tt><i>cv</i></tt> represents the member
function's cv-qualifiers); the type <tt>T1</tt> is <tt><i>cv</i> T0*</tt></ins>
</li>
</ul>
</blockquote>

<hr>
<a name="530"><h3>530.&nbsp;Must elements of a string be contiguous?</h3></a><p><b>Section:</b>&nbsp;21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Matt Austern&nbsp; <b>Date:</b>&nbsp;15 Nov 2005</p>
<p>Issue <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#69">69</a>, which was incorporated into C++03, mandated
&nbsp;&nbsp; that the elements of a vector must be stored in contiguous memory.
&nbsp;&nbsp; Should the same also apply to <tt>basic_string</tt>?</p>

<p>We almost require contiguity already. Clause 23.3.4 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-containers.html#lib.multiset"> [lib.multiset]</a>
&nbsp; defines <tt>operator[]</tt> as <tt>data()[pos]</tt>. What's missing
&nbsp; is a similar guarantee if we access the string's elements via the
&nbsp; iterator interface.</p>

<p>Given the existence of <tt>data()</tt>, and the definition of
&nbsp; <tt>operator[]</tt> and <tt>at</tt> in terms of <tt>data</tt>,
&nbsp; I don't believe it's possible to write a useful and standard-
&nbsp; conforming <tt>basic_string</tt> that isn't contiguous. I'm not
&nbsp; aware of any non-contiguous implementation. We should just require
&nbsp; it.
</p>
<p><b>Proposed resolution:</b></p>
<p>Add the following text to the end of 21.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.basic.string"> [lib.basic.string]</a>,
paragraph 2. </p>

<blockquote>
&nbsp; <p>The characters in a string are stored contiguously, meaning that if
&nbsp; <tt>s</tt> is a <tt>basic_string&lt;charT, Allocator&gt;</tt>, then
&nbsp; it obeys the identity
&nbsp; <tt>&amp;*(s.begin() + n) == &amp;*s.begin() + n</tt>
&nbsp; for all <tt>0 &lt;= n &lt; s.size()</tt>.
  </p>
</blockquote>
<hr>
<a name="533"><h3>533.&nbsp;typo in 2.2.3.10/1</h3></a><p><b>Section:</b>&nbsp;TR1 2.2.3.10 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.util.smartptr.getdeleter"> [tr.util.smartptr.getdeleter]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#DR">DR</a>&nbsp; <b>Submitter:</b>&nbsp;Paolo Carlini&nbsp; <b>Date:</b>&nbsp;9 Nov 2005</p>
<p>
I'm seeing something that looks like a typo. The Return of <tt>get_deleter</tt>
says:
</p>
<blockquote>
If <tt>*this</tt> <i>owns</i> a deleter <tt>d</tt>...
</blockquote>
<p>
but <tt>get_deleter</tt> is a free function!
</p>
<p><b>Proposed resolution:</b></p>
<p>
Therefore, I think should be:
</p>
<blockquote>
If <tt><del>*this</del> <ins>p</ins></tt> <i>owns</i> a deleter <tt>d</tt>...
</blockquote>
<hr>
<a name="535"><h3>535.&nbsp;std::string::swap specification poorly worded</h3></a><p><b>Section:</b>&nbsp;21.3.5.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-strings.html#lib.string::swap"> [lib.string::swap]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Beman Dawes&nbsp; <b>Date:</b>&nbsp;14 Dec 2005</p>
<p>
std::string::swap currently says for effects and postcondition:
</p>

<blockquote>
<p>
<i>Effects:</i> Swaps the contents of the two strings.
</p>

<p>
<i>Postcondition:</i> <tt>*this</tt> contains the characters that were in <tt><i>s</i></tt>,
<tt><i>s</i></tt> contains the characters that were in <tt>*this</tt>.
</p>
</blockquote>

<p>
Specifying both Effects and Postcondition seems redundant, and the postcondition
needs to be made stronger. Users would be unhappy if the characters were not in
the same order after the swap.
</p>
<p><b>Proposed resolution:</b></p>
<blockquote>
<p>
<del><i>Effects:</i> Swaps the contents of the two strings.</del>
</p>

<p>
<i>Postcondition:</i> <tt>*this</tt> contains the <ins>same sequence of</ins>
characters that <del>were</del> <ins>was</ins> in <tt><i>s</i></tt>,
<tt><i>s</i></tt> contains the <ins>same sequence of</ins> characters that
<del>were</del> <ins>was</ins> in <tt>*this</tt>.
</p>
</blockquote>
<hr>
<a name="537"><h3>537.&nbsp;Typos in the signatures in 27.6.1.3/42-43 and 27.6.2.4</h3></a><p><b>Section:</b>&nbsp;27.6.1.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-iostreams.html#lib.istream.unformatted"> [lib.istream.unformatted]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Paolo Carlini&nbsp; <b>Date:</b>&nbsp;12 Feb 2006</p>
<p>
In the most recent working draft, I'm still seeing:
</p>

<blockquote><pre>seekg(off_type&amp; off, ios_base::seekdir dir)
</pre></blockquote>

<p>
and
</p>

<blockquote><pre>seekp(pos_type&amp; pos)

seekp(off_type&amp; off, ios_base::seekdir dir)
</pre></blockquote>

<p>
that is, by reference off and pos arguments.
</p>
<p><b>Proposed resolution:</b></p>
<p>
After 27.6.1.3p42 change:
</p>

<blockquote><pre>basic_istream&lt;charT,traits&gt;&amp; seekg(off_type<del>&amp;</del> <i>off</i>, ios_base::seekdir <i>dir</i>);
</pre></blockquote>

<p>
After 27.6.2.4p1 change:
</p>

<blockquote><pre>basic_ostream&lt;charT,traits&gt;&amp; seekp(pos_type<del>&amp;</del> <i>pos</i>);
</pre></blockquote>

<p>
After 27.6.2.4p3 change:
</p>

<blockquote><pre>basic_ostream&lt;charT,traits&gt;&amp; seekp(off_type<del>&amp;</del> <i>off</i>, ios_base::seekdir <i>dir</i>);
</pre></blockquote>
<hr>
<a name="538"></a><h3><a name="538">538.&nbsp;241 again: Does unique_copy() require CopyConstructible and Assignable?</a></h3><p><b>Section:</b>&nbsp;25.2.8 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lib-algorithms.html#lib.alg.unique"> [lib.alg.unique]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Howard Hinnant&nbsp; <b>Date:</b>&nbsp;9 Feb 2006</p>
<p>
I believe I botched the resolution of
<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#241">
241 "Does unique_copy() require CopyConstructible and Assignable?"</a> which now
has WP status.
</p>

<p>
This talks about <tt>unique_copy</tt> requirements and currently reads:
</p>

<blockquote>
-5- <i>Requires:</i> The ranges <tt>[<i>first</i>, <i>last</i>)</tt> and
<tt>[<i>result</i>, <i>result</i>+(<i>last</i>-<i>first</i>))</tt>
shall not overlap. The expression <tt>*<i>result</i> = *<i>first</i></tt> shall
be valid. If neither <tt>InputIterator</tt> nor <tt>OutputIterator</tt> meets the
requirements of forward iterator then the value type of <tt>InputIterator</tt>
must be CopyConstructible (20.1.3). Otherwise CopyConstructible is not required.
</blockquote>

<p>
The problem (which Paolo discovered) is that when the iterators are at their
most restrictive (<tt>InputIterator</tt>, <tt>OutputIterator</tt>), then we want
<tt>InputIterator::value_type</tt> to be both <tt>CopyConstructible</tt> and
<tt>CopyAssignable</tt> (for the most efficient implementation).  However this
proposed resolution only makes it clear that it is <tt>CopyConstructible</tt>,
and that one can assign from <tt>*<i>first</i></tt> to <tt>*<i>result</i></tt>.
This latter requirement does not necessarily imply that you can:
</p>

<blockquote><pre>*<i>first</i> = *<i>first</i>;
</pre></blockquote>
<p><b>Proposed resolution:</b></p>
<blockquote>
-5- <i>Requires:</i> The ranges <tt>[<i>first</i>, <i>last</i>)</tt> and
<tt>[<i>result</i>, <i>result</i>+(<i>last</i>-<i>first</i>))</tt>
shall not overlap. The expression <tt>*<i>result</i> = *<i>first</i></tt>
shall
be valid. If neither <tt>InputIterator</tt> nor <tt>OutputIterator</tt> meets the
requirements of forward iterator then the <del>value type</del> 
<ins><tt>value_type</tt></ins> of <tt>InputIterator</tt>
must be CopyConstructible (20.1.3) <ins>and Assignable</ins>.
Otherwise CopyConstructible is not required.
</blockquote>
<hr>
<a name="540"><h3>540.&nbsp;shared_ptr&lt;void&gt;::operator*()</h3></a><p><b>Section:</b>&nbsp;TR1 2.2.3.5 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.util.smartptr.shared.obs"> [tr.util.smartptr.shared.obs]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;15 Oct 2005</p>
<p>
I'm trying to reconcile the note in tr.util.smartptr.shared.obs, p6
that talks about the operator*() member function of shared_ptr:
</p>

<blockquote>
  Notes: When T is void, attempting to instantiate this member function
  renders the program ill-formed. [Note: Instantiating shared_ptr&lt;void&gt;
  does not necessarily result in instantiating this member function.
  --end note]
</blockquote>

<p>
with the requirement in temp.inst, p1:
</p>

<blockquote>
  The implicit instantiation of a class template specialization causes
  the implicit instantiation of the declarations, but not of the
  definitions...
</blockquote>

<p>
I assume that what the note is really trying to say is that
"instantiating shared_ptr&lt;void&gt; *must not* result in instantiating
this member function." That is, that this function must not be
declared a member of shared_ptr&lt;void&gt;. Is my interpretation
correct?
</p>
<p><b>Proposed resolution:</b></p>
<p>
Change 2.2.3.5p6
</p>

<blockquote>
-6- <del><i>Notes:</i></del> When <tt>T</tt> is <tt>void</tt>, <del>attempting to instantiate
this member function renders the program ill-formed. [<i>Note:</i>
Instantiating <tt>shared_ptr&lt;void&gt;</tt> does not necessarily result in
instantiating this member function. <i>--end note</i>]</del> <ins>it is
unspecified whether this member function is declared or not, and if so, what its
return type is, except that the declaration (although not necessarily the
definition) of the function shall be well-formed.</ins>
</blockquote>

<hr>
<a name="541"><h3>541.&nbsp;shared_ptr template assignment and void</h3></a><p><b>Section:</b>&nbsp;TR1 2.2.3 <a href="http://www.open-std.org/jtc1/sc22/wg21/docs/tr1.html#tr.util.smartptr.shared"> [tr.util.smartptr.shared]</a>&nbsp; <b>Status:</b>&nbsp;<a href="http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#WP">WP</a>&nbsp; <b>Submitter:</b>&nbsp;Martin Sebor&nbsp; <b>Date:</b>&nbsp;16 Oct 2005</p>
<p>
Is the void specialization of the template assignment operator taking
a shared_ptr&lt;void&gt; as an argument supposed be well-formed?
</p>
<p>
I.e., is this snippet well-formed:
</p>
<blockquote><pre>shared_ptr&lt;void&gt; p;
p.operator=&lt;void&gt;(p);
</pre></blockquote>

<p>
Gcc complains about auto_ptr&lt;void&gt;::operator*() returning a reference
to void. I suspect it's because shared_ptr has two template assignment
operators, one of which takes auto_ptr, and the auto_ptr template gets
implicitly instantiated in the process of overload resolution.
</p>

<p>
The only way I see around it is to do the same trick with auto_ptr&lt;void&gt;
operator*() as with the same operator in shared_ptr&lt;void&gt;.
</p>

<p>
PS Strangely enough, the EDG front end doesn't mind the code, even
though in a small test case (below) I can reproduce the error with
it as well.
</p>

<blockquote><pre>template &lt;class T&gt;
struct A { T&amp; operator*() { return *(T*)0; } };

template &lt;class T&gt;
struct B {
    void operator= (const B&amp;) { }
    template &lt;class U&gt;
    void operator= (const B&lt;U&gt;&amp;) { }
    template &lt;class U&gt;
    void operator= (const A&lt;U&gt;&amp;) { }
};

int main ()
{
    B&lt;void&gt; b;
    b.operator=&lt;void&gt;(b);
}
</pre></blockquote>
<p><b>Proposed resolution:</b></p>
<p>
In [lib.memory] change:
</p>
<blockquote><pre>template&lt;class X&gt; class auto_ptr;
<ins>template&lt;&gt; class auto_ptr&lt;void&gt;;</ins>
</pre></blockquote>

<p>
In [lib.auto.ptr]/2 add the following before the last closing brace:
</p>

<blockquote><pre>template&lt;&gt; class auto_ptr&lt;void&gt;
{
public:
&nbsp; &nbsp; typedef void element_type;
};
</pre></blockquote>

<p>----- End of document -----</p>
</body></html>
generated by cgit v1.2.3 (git 2.25.1) at 2024-06-18 19:54:45 +0000