diff options
Diffstat (limited to 'libstdc++-v3/include')
| -rw-r--r-- | libstdc++-v3/include/std/istream | 13 | ||||
| -rw-r--r-- | libstdc++-v3/include/std/ostream | 36 |
2 files changed, 26 insertions, 23 deletions
diff --git a/libstdc++-v3/include/std/istream b/libstdc++-v3/include/std/istream index ea34cce..5ad60db 100644 --- a/libstdc++-v3/include/std/istream +++ b/libstdc++-v3/include/std/istream @@ -958,12 +958,17 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // 2328. Rvalue stream extraction should use perfect forwarding // 1203. More useful rvalue stream insertion - // SFINAE helper to check constraints for operator>>(Istream&&, T&&). - // If the constraints are satisfied, it is an alias for Istream&&. +#if __cpp_lib_concepts + template<typename _Is, typename _Tp> + requires __derived_from_ios_base<_Is> + && requires (_Is& __is, _Tp&& __t) { __is >> std::forward<_Tp>(__t); } + using __rvalue_stream_extraction_t = _Is&&; +#else template<typename _Is, typename _Tp, - typename = decltype(std::__rval_streamable<_Is>() - >> std::declval<_Tp>())> + typename = _Require_derived_from_ios_base<_Is>, + typename = decltype(std::declval<_Is&>() >> std::declval<_Tp>())> using __rvalue_stream_extraction_t = _Is&&; +#endif /** * @brief Generic extractor for rvalue stream diff --git a/libstdc++-v3/include/std/ostream b/libstdc++-v3/include/std/ostream index fdd2a87..9816973 100644 --- a/libstdc++-v3/include/std/ostream +++ b/libstdc++-v3/include/std/ostream @@ -708,31 +708,29 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION // _GLIBCXX_RESOLVE_LIB_DEFECTS // 1203. More useful rvalue stream insertion - // SFINAE helper to check constraints for operator<<(Ostream&&, const T&). - // If Ostream is publicly and unambiguously derived from ios_base, then - // __rval_streamable<Ostream>() is equivalent to declval<Ostream&>(). - // Otherwise, it results in a substitution failure. Specifically, it will - // fail if Ostream is an lvalue reference or the same type as ios_base. - // Use concepts if possible because they're cheaper to evaluate. #if __cpp_lib_concepts + // Use concepts if possible because they're cheaper to evaluate. template<typename _Tp> - requires (!is_same_v<_Tp, ios_base>) - && requires (_Tp* __t, ios_base* __b) { __b = __t; } - _Tp& - __rval_streamable(); + concept __derived_from_ios_base = is_class_v<_Tp> + && (!is_same_v<_Tp, ios_base>) + && requires (_Tp* __t, ios_base* __b) { __b = __t; }; + + template<typename _Os, typename _Tp> + requires __derived_from_ios_base<_Os> + && requires (_Os& __os, const _Tp& __t) { __os << __t; } + using __rvalue_stream_insertion_t = _Os&&; #else - template<typename _Tp, - typename = _Require<__not_<__is_one_of<_Tp, _Tp&, ios_base>>>> - _Tp& - __rval_streamable(ios_base* = (_Tp*)nullptr); -#endif + template<typename _Tp> + using _Require_derived_from_ios_base + = _Require<is_class<_Tp>, __not_<is_same<_Tp, ios_base>>, + is_convertible<typename add_pointer<_Tp>::type, ios_base*>>; - // SFINAE helper to check constraints for operator<<(Ostream&&, const T&). - // If the constraints are satisfied, it is an alias for Ostream&&. template<typename _Os, typename _Tp, - typename = decltype(std::__rval_streamable<_Os>() - << std::declval<const _Tp&>())> + typename = _Require_derived_from_ios_base<_Os>, + typename + = decltype(std::declval<_Os&>() << std::declval<const _Tp&>())> using __rvalue_stream_insertion_t = _Os&&; +#endif /** * @brief Generic inserter for rvalue stream |