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<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META NAME="KEYWORDS" CONTENT="libstdc++, libstdc++-v3, GCC, g++, libg++, STL">
<META NAME="DESCRIPTION" CONTENT="FAQ for the GNU libstdc++ effort.">
<TITLE>libstdc++-v3 FAQ</TITLE>
<LINK REL=StyleSheet HREF="../lib3styles.css">
<!--
** Locations of "the most recent snapshot is the Nth" text are
** answers 1_1, 1_4, 4_1, 5_6.
-->
<!-- $Id: index.html,v 1.2.4.3 2001/05/14 19:48:58 bkoz Exp $ -->
</HEAD>
<BODY>
<H1 CLASS="centered">libstdc++ Frequently Asked Questions</H1>
<P>The latest version of this document is always available at
<A HREF="http://gcc.gnu.org/onlinedocs/libstdc++/faq/">
http://gcc.gnu.org/onlinedocs/libstdc++/faq/</A>.</P>
<P>To the <A HREF="http://gcc.gnu.org/libstdc++/">libstdc++-v3 homepage</A>.
<!-- ####################################################### -->
<HR>
<H1>Questions</H1>
<OL>
<LI><A HREF="#1_0">General Information</A>
<!-- I suspect these will mostly be links to/into existing documents. -->
<OL>
<LI><A HREF="#1_1">What is libstdc++-v3?</A>
<LI><A HREF="#1_2">Why should I use libstdc++?</A>
<LI><A HREF="#1_3">Who's in charge of it?</A>
<LI><A HREF="#1_4">How do I get libstdc++?</A>
<LI><A HREF="#1_5">When is libstdc++ going to be finished?</A>
<LI><A HREF="#1_6">How do I contribute to the effort?</A>
<LI><A HREF="#1_7">What happened to libg++? I need that!</A>
<LI><A HREF="#1_8">What if I have more questions?</A>
</OL>
<LI><A HREF="#2_0">Installation</A>
<OL>
<LI><A HREF="#2_1">How do I install libstdc++-v3?</A>
<LI><A HREF="#2_2">[removed]</A>
<LI><A HREF="#2_3">What is this CVS thing that you keep
mentioning?</A>
<LI><A HREF="#2_4">How do I know if it works?</A>
</OL>
<LI><A HREF="#3_0">Platform-Specific Issues</A>
<OL>
<LI><A HREF="#3_1">Can libstdc++-v3 be used with <my
favorite compiler>?</A>
<LI><A HREF="#3_2">[removed]</A>
<LI><A HREF="#3_3">Building under DEC OSF kills the assembler</A>
</OL>
<LI><A HREF="#4_0">Known Bugs and Non-Bugs</A>
<OL>
<LI><A HREF="#4_1">What works already?</A>
<LI><A HREF="#4_2">Bugs in gcc/g++ (not libstdc++-v3)</A>
<LI><A HREF="#4_3">Bugs in the C++ language/lib specification</A>
<LI><A HREF="#4_4">Things in libstdc++ that look like bugs</A>
<UL>
<LI><A HREF="#4_4_Weff">-Weffc++ complains too much</A>
<LI><A HREF="#4_4_rel_ops">"ambiguous overloads"
after including an old-style header</A>
<LI><A HREF="#4_4_interface">The g++-3 headers are
<STRONG>not ours</STRONG></A>
<LI><A HREF="#4_4_glibc">compilation errors from streambuf.h</A>
<LI><A HREF="#4_4_checks">errors about <EM>*Cconcept</EM> and
<EM>constraints</EM> in the STL...</A>
</UL>
<LI><A HREF="#4_5">Aw, that's easy to fix!</A>
</OL>
<LI><A HREF="#5_0">Miscellaneous</A>
<OL>
<LI><A HREF="#5_1">string::iterator is not char*;
vector<T>::iterator is not T*</A>
<LI><A HREF="#5_2">What's next after libstdc++-v3?</A>
<LI><A HREF="#5_3">What about the STL from SGI?</A>
<LI><A HREF="#5_4">Extensions and Backward Compatibility</A>
<LI><A HREF="#5_5">[removed]</A>
<LI><A HREF="#5_6">Is libstdc++-v3 thread-safe?</A>
<LI><A HREF="#5_7">How do I get a copy of the ISO C++ Standard?</A>
</OL>
</OL>
<HR>
<!-- ####################################################### -->
<H1><A NAME="1_0">1.0 General Information</A></H1>
<!-- I suspect these will mostly be links to/into existing documents. -->
<H2><A NAME="1_1">1.1 What is libstdc++-v3?</A></H2>
<P>The GNU Standard C++ Library v3, or libstdc++-2.9x, is an
ongoing project to implement the ISO 14882 Standard C++ library
as described in chapters 17 through 27 and annex D. As the
library reaches stable plateaus, it is captured in a snapshot
and released. The current release is <A
HREF="ftp://gcc.gnu.org/pub/libstdc++/libstdc++-2.92.tar.gz">the
eleventh snapshot</A>. For those who want to see exactly how
far the project has come, or just want the latest
bleeding-edge code, the up-to-date source is available over
anonymous CVS, and can even be browsed over the Web (see below).
</P>
<P>A more formal description of the V3 goals can be found in the
official <A HREF="../17_intro/DESIGN">design document</A>.
</P>
<HR>
<H2><A NAME="1_2">1.2 Why should I use libstdc++?</A></H2>
<P>The completion of the ISO C++ standardization gave the
C++ community a powerful set of reuseable tools in the form
of the C++ Standard Library. However, all existing C++
implementations are (as the Draft Standard used to say)
"incomplet and incorrekt," and many suffer from
limitations of the compilers that use them.
</P>
<P>The GNU C/C++/FORTRAN/<pick-a-language> compiler
(<TT>gcc</TT>, <TT>g++</TT>, etc) is widely considered to be
one of the leading compilers in the world. Its development
has recently been taken over by the
<A HREF="http://gcc.gnu.org/">GCC team</A>. All of
the rapid development and near-legendary
<A
HREF="http://gcc.gnu.org/gcc-2.95/buildstat.html">portability</A>
that are the hallmarks of an open-source project are being
applied to libstdc++.
</P>
<P>That means that all of the Standard classes and functions
(such as <TT>string</TT>, <TT>vector<></TT>, iostreams,
and algorithms) will be freely available and fully compliant.
Programmers will no longer need to "roll their own"
nor be worried about platform-specific incompatabilities.
</P>
<HR>
<H2><A NAME="1_3">1.3 Who's in charge of it?</A></H2>
<P>The libstdc++ project is contributed to by several developers
all over the world, in the same way as GCC or Linux.
Benjamin Kosnik, Gabriel Dos Reis, Phil Edwards, and Ulrich
Drepper are the lead maintainers of the CVS archive.
</P>
<P>Development and discussion is held on the libstdc++ mailing
list. Subscribing to the list, or searching the list
archives, is open to everyone. You can read instructions for
doing so on the <A HREF="http://gcc.gnu.org/libstdc++/">homepage</A>.
If you have questions, ideas, code, or are just curious, sign up!
</P>
<HR>
<H2><A NAME="1_4">1.4 How do I get libstdc++?</A></H2>
<P>The eleventh (and latest) snapshot of libstdc++-v3 is <A
HREF="ftp://gcc.gnu.org/pub/libstdc++/libstdc++-2.92.tar.gz">
available via ftp</A>.
</P>
<P>The <A HREF="http://gcc.gnu.org/libstdc++/">homepage</A>
has instructions for retrieving the latest CVS sources, and for
browsing the CVS sources over the web.
</P>
<P>The subset commonly known as the Standard Template Library
(chapters 23 through 25, mostly) is adapted from the SGI STL,
which is also an ongoing work.<!-- Possibly a link to SGI's
STL here. -->
</P>
<HR>
<H2><A NAME="1_5">1.5 When is libstdc++ going to be finished?</A></H2>
<!-- <P>Nathan Myers gave the best of all possible answers in <A
HREF="http://www.deja.com/getdoc.xp?AN=469581698&fmt=text">a
Usenet article</A>.</P>
which is no longer available, thanks deja...-->
<P>Nathan Myers gave the best of all possible answers, responding to a
Usenet article asking this question: <EM>Sooner, if you help.</EM>
</P>
<HR>
<H2><A NAME="1_6">1.6 How do I contribute to the effort?</A></H2>
<P>Here is <A HREF="../17_intro/contribute.html">a
page devoted to this topic</A>. Subscribing to the mailing
list (see above, or the homepage) is a very good idea if you
have something to contribute, or if you have spare time and
want to help. Contributions don't have to be in the form of
source code; anybody who is willing to help write
documentation, for example, or has found a bug in code that
we all thought was working, is more than welcome!
</P>
<HR>
<H2><A NAME="1_7">1.7 What happened to libg++? I need that!</A></H2>
<P>The most recent libg++ README states that libg++ is no longer
being actively maintained. It should not be used for new
projects, and is only being kicked along to support older code.
</P>
<P>The libg++ was designed and created when there was no Standard
to provide guidance. Classes like linked lists are now provided
for by <TT>list<T></TT> and do not need to be created by
<TT>genclass</TT>. (For that matter, templates exist now and
are well-supported, whereas genclass (mostly) predates them.)
</P>
<P>There are other classes in libg++ that are not specified in the
ISO Standard (e.g., statistical analysis). While there are a
lot of really useful things that are used by a lot of people
(e.g., statistics :-), the Standards Committee couldn't include
everything, and so a lot of those "obvious" classes
didn't get included.
</P>
<P>Since libstdc++ is an implementation of the Standard Library, we
have no plans at this time to include non-Standard utilities
in the implementation, however handy they are. (The extensions
provided in the SGI STL aren't maintained by us and don't get
a lot of our attention, because they don't require a lot of our
time.) It is entirely plausable that the "useful stuff"
from libg++ might be extracted into an updated utilities library,
but nobody has stated such a project yet.
</P>
<!-- The advertisement, so to speak, might have to go. Hmmmmm. -->
<P>(The <A HREF="http://www.boost.org/">Boost</A> site houses free
C++ libraries that do varying things, and happened to be started
by members of the Standards Committee. Certain "useful
stuff" classes will probably migrate there.)
</P>
<P>For the bold and/or desperate, the
<A HREF="http://gcc.gnu.org/fom_serv/cache/33.html">GCC FAQ</A>
describes where to find the last libg++ source.
</P>
<HR>
<H2><A NAME="1_8">1.8 What if I have more questions?</A></H2>
<P>If you have read the README and RELEASE-NOTES files, and your
question remains unanswered, then just ask the mailing list.
At present, you do not need to be subscribed to the list to
send a message to it. More information is available on the
homepage (including how to browse the list archives); to send
to the list, use <A HREF="mailto:libstdc++@gcc.gnu.org">
<CODE>libstdc++@gcc.gnu.org</CODE></A>.
</P>
<P>If you have a question that you think should be included here,
or if you have a question <EM>about</EM> a question/answer here,
contact <A HREF="mailto:pme@sources.redhat.com">Phil Edwards</A>
or <A HREF="mailto:gdr@gcc.gnu.org">Gabriel Dos Reis</A>.
</P>
<HR>
<H1><A NAME="2_0">2.0 Installation</A></H1>
<H2><A NAME="2_1">2.1 How do I install libstdc++-v3?</A></H2>
<P>Complete instructions are not given here (this is a FAQ, not
an installation document), but the tools required are few:
</P>
<UL>
<LI> A 3.x release of GCC. Note that building GCC is much
easier and more automated than building the GCC 2.[78]
series was. If you are using GCC 2.95, you can still
build earlier snapshots of libstdc++.
<LI> GNU Make is the only make that supports these makefiles.
<LI> The GNU Autotools are needed if you are messing with
the configury or makefiles.
</UL>
<P>The file <A HREF="../documentation.html">documentation.html</A>
provides a good overview of the steps necessary to build, install,
and use the library. Instructions for configuring the library
with new flags such as --enable-threads are there also, as well as
patches and instructions for working with GCC 2.95.
</P>
<P>The top-level install.html and
<A HREF="../17_intro/RELEASE-NOTES">RELEASE-NOTES</A> files contain
the exact build and installation instructions. You may wish to
browse those files over CVSweb ahead of time to get a feel for
what's required. RELEASE-NOTES is located in the
".../docs/17_intro/" directory of the distribution.
</P>
<HR>
<H2><A NAME="2_2">2.2 [removed]</A></H2>
<P>This question has become moot and has been removed. The stub
is here to preserve numbering (and hence links/bookmarks).
</P>
<HR>
<H2><A NAME="2_3">2.3 What is this CVS thing that you
keep mentioning?</A></H2>
<P>The <EM>Concurrent Versions System</EM> is one of several revision
control packages. It was selected for GNU projects because it's
free (speech), free (beer), and very high quality. The <A
HREF="http://www.gnu.org/software/cvs/cvs.html">CVS entry in
the GNU software catalogue</A> has a better description as
well as a
<A HREF="http://www.cvshome.org/">link to the makers of CVS</A>.
</P>
<P>The "anonymous client checkout" feature of CVS is
similar to anonymous FTP in that it allows anyone to retrieve
the latest libstdc++ sources.
</P>
<P>After the first of April, American users will have a
"/pharmacy" command-line option...
<!-- wonder how long that'll live -->
</P>
<HR>
<H2><A NAME="2_4">2.4 How do I know if it works?</A></H2>
<P>libstdc++-v3 comes with its own testsuite. You do not need
to actually install the library ("<TT>gmake
install</TT>") to run the testsuite.
</P>
<P>To run the testsuite on the library after building it, use
"gmake check" while in your build directory. To run
the testsuite on the library after building and installing it,
use "gmake check-install" instead.
</P>
<P>If you find bugs in the testsuite programs themselves, or if
you think of a new test program that should be added to the
suite, <B>please</B> write up your idea and send it to the list!
</P>
<HR>
<H1><A NAME="3_0">3.0 Platform-Specific Issues</A></H1>
<H2><A NAME="3_1">3.1 Can libstdc++-v3 be used with <my
favorite compiler>?</A></H2>
<P>Probably not. Yet.</P>
<P>Because GCC advances so rapidly, development and testing of
libstdc++ is being done almost entirely under that compiler.
If you are curious about whether other, lesser compilers
(*grin*) support libstdc++, you are more than welcome to try.
Configuring and building the library (see above) will still
require certain tools, however. Also keep in mind that
<EM>building</EM> libstdc++ does not imply that your compiler
will be able to <EM>use</EM> all of the features found in the
C++ Standard Library.
</P>
<P>Since the goal of ISO Standardization is for all C++
implementations to be able to share code, the final libstdc++
should, in theory, be useable under any ISO-compliant
compiler. It will still be targeted and optimized for
GCC/g++, however.
</P>
<HR>
<H2><A NAME="3_2">3.2 [removed]</A></H2>
<P>This question has become moot and has been removed. The stub
is here to preserve numbering (and hence links/bookmarks).
</P>
<HR>
<H2><A NAME="3_3">3.3 Building DEC OSF kills the assembler</A></H2>
<P>The <TT>atomicity.h</TT> header for the Alpha processor
currently uses pseudo-operators which the DEC assembler
doesn't understand (in particular, .subsection and .previous).
The simple solution is to install GNU <TT>as</TT> and arrange
for the GCC build to use it (or merge the sources and build
it during the bootstrap).
</P>
<P>Anyone who
<A HREF="http://gcc.gnu.org/ml/libstdc++/2000-12/msg00279.html">knows
the DEC assembler well enough</A> to provide the equivalent of
these two pseudos would win praise and accolades from many.
</P>
<HR>
<H1><A NAME="4_0">4.0 Known Bugs and Non-Bugs</A></H1>
<EM>Note that this section can get rapdily outdated -- such is the
nature of an open-source project. For the latest information, join
the mailing list or look through recent archives. The RELEASE-
NOTES and BUGS files are generally kept up-to-date.</EM>
<H2><A NAME="4_1">4.1 What works already?</A></H2>
<P>This is a verbatim clip from the "Status" section
of the RELEASE-NOTES for the latest snapshot.
</P>
<!-- Yeah, I meant that "verbatim clip" thing literally... :-) -->
<pre>
New:
---
- preliminary doxygen documentation has been added. Running "make
doxygen" in the libstdc++-v3 build directory will generate HTML
documentation that can be used to cross-reference names and files in
the library.
- a dejagnu based testing framework has been added
- a new implementation of the concept checking code has been ported
from the boost libraries.
- support for -fno-exceptions has been added
- stdexcept was re-written
- using deprecated or antiquated headers now gives a warning
- the stdio interface to iostreams has been tweaked, and now works
with synchronized c/c++ io
- new libsupc++ routines implementing the IA-64 C++ ABI.
- HPUX configuration files
- support for AIX added
- a lot of bugs were fixed.
- preliminary named locales implemented
- portability improvements made to generation of <limits>
- speedups to improve configuration time.
- DJGPP support added.
- support for dlopening shared libstdc++
</pre>
<HR>
<H2><A NAME="4_2">4.2 Bugs in gcc/g++ (not libstdc++-v3)</A></H2>
<P>This is by no means meant to be complete nor exhaustive, but
mentions some problems that users may encounter when building
or using libstdc++. If you are experiencing one of these
problems, you can find more information on the libstdc++ and
the GCC mailing lists.
</P>
<UL>
<LI>As of 2.91, these bugs have all been fixed. We look forward
to new ones, well, not exactly...
</UL>
<HR>
<H2><A NAME="4_3">4.3 Bugs in the C++ language/lib specification</A></H2>
<P>Yes, unfortunately, there are some. In a <A
HREF="http://gcc.gnu.org/ml/libstdc++/1998/msg00006.html">message
to the list</A>, Nathan Myers announced that he has started a list of
problems in the ISO C++ Standard itself, especially with
regard to the chapters that concern the library. The list
itself is <A
HREF="http://www.cantrip.org/draft-bugs.txt">posted on his
website</A>. Developers who are having problems interpreting
the Standard may wish to consult his notes.
</P>
<P>For those people who are not part of the ISO Library Group
(i.e., nearly all of us needing to read this page in the first
place :-), a public list of the library defects is occasionally
published <A HREF="http://anubis.dkuug.dk/jtc1/sc22/wg21/">here</A>.
</P>
<HR>
<H2><A NAME="4_4">4.4 Things in libstdc++ that look like bugs</A></H2>
<P>There are things which are not bugs in the compiler (4.2) nor
the language specification (4.3), but aren't really bugs in
libstdc++, either. Really! Please do not report these as bugs.
</P>
<A NAME="4_4_Weff">
<P><STRONG>-Weffc++</STRONG>
The biggest of these is the quadzillions of warnings about the
library headers emitted when <TT>-Weffc++</TT> is used. Making
libstdc++ "-Weffc++-clean" is not a goal of the project,
for a few reasons. Mainly, that option tries to enforce
object-oriented programming, while the Standard Library isn't
necessarily trying to be OO. There are multiple solutions
under discussion.
</P>
</A>
<A NAME="4_4_rel_ops">
<P><STRONG>rel_ops</STRONG>
Another is the <TT>rel_ops</TT> namespace and the template
comparison operator functions contained therein. If they become
visible in the same namespace as other comparison functions
(e.g., '<TT>using</TT>' them and the <iterator> header),
then you will suddenly be faced with huge numbers of ambiguity
errors. This was discussed on the -v3 list; Nathan Myers
<A HREF="http://gcc.gnu.org/ml/libstdc++/2001-01/msg00247.html">sums
things up here</A>.
</P>
</A>
<A NAME="4_4_interface"><H3>The g++-3 headers are
<EM>not ours</EM></H3>
<P>If you have found an extremely broken header file which is
causing problems for you, look carefully before submitting a
"high" priority bug report (which you probably shouldn't
do anyhow; see the last paragraph of the page describing
<A HREF="http://gcc.gnu.org/gnatswrite.html">the GCC bug database</A>).
</P>
<P>If the headers are in <CODE>${prefix}/include/g++-3</CODE>, then
you are using the old libstdc++-v2 library, which is nonstandard
and unmaintained. Do not report problems with -v2 to the -v3
mailing list.
</P>
<P>Currently our header files are installed in
<CODE>${prefix}/include/g++-v3</CODE> (see the 'v'?). This may
change with the next release of GCC, as it may be too confusing,
but <A HREF="http://gcc.gnu.org/ml/gcc/2000-10/msg00732.html">the
question has not yet been decided</A>.
</P>
</A>
<A NAME="4_4_glibc">
<P><STRONG>glibc</STRONG>
If you're on a GNU/Linux system and have just upgraded to
glibc 2.2, but are still using gcc 2.95.2, then you should have
read the glibc FAQ, specifically 2.34:
<PRE>
2.34. When compiling C++ programs, I get a compilation error in streambuf.h.
{BH} You are using g++ 2.95.2? After upgrading to glibc 2.2, you need to
apply a patch to the include files in /usr/include/g++, because the fpos_t
type has changed in glibc 2.2. The patch is at
http://clisp.cons.org/~haible/gccinclude-glibc-2.2-compat.diff
</PRE>
Note that 2.95.x shipped with the
<A HREF="#4_4_interface">old v2 library</A> which is no longer
maintained. Also note that gcc 2.95.3 fixes this problem, but
requires a separate patch for libstdc++-v3.
</P>
</A>
<A NAME="4_4_checks">
<P><STRONG>concept checks</STRONG>
If you see compilation errors containing messages about
<TT> <EM>foo</EM>Concept </TT>and a<TT> constraints </TT>
member function, then most likely you have violated one of the
requirements for types used during instantiation of template
containers and functions. For example, EqualityComparableConcept
appears if your types must be comparable with == and you have not
provided this capability (a typo, or wrong visibility, or you
just plain forgot, etc).
</P>
<P>More information, including how to optionally enable/disable the
checks, is available
<A HREF="../19_diagnostics/howto.html#3">here</A>.
</P>
</A>
<HR>
<H2><A NAME="4_5">4.5 Aw, that's easy to fix!</A></H2>
<P>If you have found a bug in the library and you think you have
a working fix, then send it in! The main GCC site has a page
on <A HREF="http://gcc.gnu.org/contribute.html">submitting
patches</A> that covers the procedure, but for libstdc++ you
should also send the patch to our mailing list in addition to
the GCC patches mailing list. The libstdc++
<A HREF="../17_intro/contribute.html">contributors' page</A>
also talks about how to submit patches.
</P>
<P>In addition to the description, the patch, and the ChangeLog
entry, it is a Good Thing if you can additionally create a small
test program to test for the presence of the bug that your
patch fixes. Bugs have a way of being reintroduced; if an old
bug creeps back in, it will be caught immediately by the
<A HREF="#2_4">testsuite</A> -- but only if such a test exists.
</P>
<HR>
<H1><A NAME="5_0">5.0 Miscellaneous</A></H1>
<H2><A NAME="5_1">5.1 string::iterator is not char*;
vector<T>::iterator is not T*</A></H2>
<P>If you have code that depends on container<T> iterators
being implemented as pointer-to-T, your code is broken.
</P>
<P>While there are arguments for iterators to be implemented in
that manner, A) they aren't very good ones in the long term,
and B) they were never guaranteed by the Standard anyway. The
type-safety achieved by making iterators a real class rather
than a typedef for <TT>T*</TT> outweighs nearly all opposing
arguments.
</P>
<HR>
<H2><A NAME="5_2">5.2 What's next after libstdc++-v3?</A></H2>
<P>Hopefully, not much. The goal of libstdc++-v3 is to produce
a fully-compliant, fully-portable Standard Library. After that,
we're mostly done: there won't <EM>be</EM> any more compliance
work to do.
</P>
<P>The ISO Committee will meet periodically to review Defect Reports
in the C++ Standard. Undoubtedly some of these will result in
changes to the Standard, which will be reflected in patches to
libstdc++. Some of that is already happening, see 4.2. Some of
those changes are being predicted by the library maintainers, and
we add code to the library based on what the current proposed
resolution specifies.
</P>
<P>The current libstdc++ contains extensions to the Library which
must be explicitly requested by client code (for example, the
hash tables from SGI). Other extensions may be added to
libstdc++-v3 if they seem to be "standard" enough.
(For example, the "long long" type from C99.)
Bugfixes and rewrites (to improve or fix thread safety, for
instance) will of course be a continuing task.
</P>
<P><A
HREF="http://gcc.gnu.org/ml/libstdc++/1999/msg00080.html">This
question</A> about the next libstdc++ prompted some brief but
interesting <A
HREF="http://gcc.gnu.org/ml/libstdc++/1999/msg00084.html">speculation</A>.
</P>
<HR>
<H2><A NAME="5_3">5.3 What about the STL from SGI?</A></H2>
<P>The <A HREF="http://www.sgi.com/Technology/STL/">STL from SGI</A>
is merged into libstdc++-v3 with changes as necessary.
Currently release 3.3 is being used as an initial codebase, plus
changes, fixes, and extensions.
</P>
<P>In particular, <TT>string</TT> is not from SGI and makes no
use of their "rope" class (which is included as an
optional extension), nor is <TT>valarray</TT> and some others.
Classes like <TT>vector<></TT> are, however.
</P>
<P>The FAQ for SGI's STL (one jump off of their main page) is
recommended reading.
</P>
<HR>
<H2><A NAME="5_4">5.4 Extensions and Backward Compatibility</A></H2>
<P>Although you can specify <TT>-I</TT> options to make the
preprocessor search the g++-v3/ext and /backward directories,
it is better to refer to files there by their path, as in:
<!-- Careful, the leading spaces in PRE show up directly. -->
</P>
<PRE>
#include <ext/hash_map>
</PRE>
<P>Extensions to the library have
<A HREF="../ext/howto.html">their own page</A>.
</P>
<HR>
<H2><A NAME="5_5">5.5 [removed]</A></H2>
<P>This question has become moot and has been removed. The stub
is here to preserve numbering (and hence links/bookmarks).
</P>
<HR>
<H2><A NAME="5_6">5.6 Is libstdc++-v3 thread-safe?</A></H2>
<P>Quick answer: no, as of 2.92 (eleventh snapshot), the
library is not appropriate for multithreaded access. The
string class is MT-safe.
</P>
<P>This is assuming that your idea of "multithreaded"
is the same as ours... The general question of multithreading
and libstdc++-v3 is addressed in the chapter-specific advice for
<A HREF="http://gcc.gnu.org/onlinedocs/libstdc++/17_intro/howto.html#3">Library
Introduction</A>. Threadsafe containers are covered in
more detail in
<A HREF="http://gcc.gnu.org/onlinedocs/libstdc++/23_containers/howto.html">the
Received Wisdom section on containers</A>.
<!-- I have successfully evaded the topic; my work here is
done- no, wait, I have to write those other sections... -->
</P>
<HR>
<H2><A NAME="5_7">5.7 How do I get a copy of the ISO C++ Standard?</A></H2>
<P>Copies of the full ISO 14882 standard are available on line via the
ISO mirror site for committee members. Non-members, or those who
have not paid for the privilege of sitting on the committee and
sustained their two-meeting commitment for voting rights, may get a
copy of the standard from their respective national standards
organization. In the USA, this national standards organization is
ANSI and their website is right <A HREF="http://www.ansi.org">here</A>.
(And if you've already registered with them, clicking this link will
take you to directly to the place where you can
<A HREF="http://webstore.ansi.org/ansidocstore/product.asp?sku=ISO%2FIEC+14882%2D1998">buy
the standard on-line</A>.
</P>
<P>Who is your country's member body? Visit the
<A HREF="http://www.iso.ch/">ISO homepage</A> and find out!
</P>
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