diff options
Diffstat (limited to 'libstdc++-v3/include/tr1/type_traits')
| -rw-r--r-- | libstdc++-v3/include/tr1/type_traits | 34 |
1 files changed, 31 insertions, 3 deletions
diff --git a/libstdc++-v3/include/tr1/type_traits b/libstdc++-v3/include/tr1/type_traits index d75e5dffb10..753722941f9 100644 --- a/libstdc++-v3/include/tr1/type_traits +++ b/libstdc++-v3/include/tr1/type_traits @@ -477,10 +477,38 @@ namespace tr1 remove_all_extents<_Tp>::type>::value)> { }; + template<typename> + struct __is_empty_helper_1 + { }; + + template<typename _Tp> + struct __is_empty_helper_2 + : public _Tp { }; + + // Unfortunately, without compiler support we cannot tell union from + // class types, and is_empty doesn't work at all with the former. + template<typename _Tp, bool = (is_fundamental<_Tp>::value + || is_array<_Tp>::value + || is_pointer<_Tp>::value + || is_reference<_Tp>::value + || is_member_pointer<_Tp>::value + || is_enum<_Tp>::value + || is_function<_Tp>::value)> + struct __is_empty_helper + { static const bool __value = (sizeof(__is_empty_helper_1<_Tp>) + == sizeof(__is_empty_helper_2<_Tp>)); }; + + template<typename _Tp> + struct __is_empty_helper<_Tp, true> + { static const bool __value = false; }; + + template<typename _Tp> + struct is_empty + : public integral_constant<bool, __is_empty_helper<_Tp>::__value> + { }; + // Exploit the resolution DR core/337. - template<typename _Tp, bool = (is_void<_Tp>::value - || is_function<_Tp>::value - || is_reference<_Tp>::value)> + template<typename _Tp, bool = !is_object<_Tp>::value> struct __is_abstract_helper : public __sfinae_types { |