This is a tiny feature, small but perfectly formed. And easy to implement.
* include/std/type_traits (endian): Define new enumeration type. * testsuite/20_util/endian/1.cc: New test. Tested powerpc64le-linux, committed to trunk.
commit ad69c5875cdefc5c699b50975ee6016a424d450b Author: Jonathan Wakely <jwak...@redhat.com> Date: Fri Nov 3 15:04:51 2017 +0000 Define std::endian for C++2a (P0463R1) * include/std/type_traits (endian): Define new enumeration type. * testsuite/20_util/endian/1.cc: New test. diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits index 036f7667bd8..7eca08c1a50 100644 --- a/libstdc++-v3/include/std/type_traits +++ b/libstdc++-v3/include/std/type_traits @@ -2664,7 +2664,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION void operator=(__nonesuch const&) = delete; }; -#if __cplusplus > 201402L +#if __cplusplus >= 201703L # define __cpp_lib_is_invocable 201703 /// std::invoke_result @@ -2739,7 +2739,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION = is_nothrow_invocable_r<_Fn, _Args...>::value; #endif // C++17 -#if __cplusplus > 201402L +#if __cplusplus >= 201703L # define __cpp_lib_type_trait_variable_templates 201510L template <typename _Tp> inline constexpr bool is_void_v = is_void<_Tp>::value; @@ -2943,6 +2943,16 @@ template <typename _From, typename _To> #endif // C++17 +#if __cplusplus > 201703L + /// Byte order + enum class endian + { + little = __ORDER_LITTLE_ENDIAN__, + big = __ORDER_BIG_ENDIAN__, + native = __BYTE_ORDER__ + }; +#endif // C++2a + _GLIBCXX_END_NAMESPACE_VERSION } // namespace std diff --git a/libstdc++-v3/testsuite/20_util/endian/1.cc b/libstdc++-v3/testsuite/20_util/endian/1.cc new file mode 100644 index 00000000000..2720c5edcdb --- /dev/null +++ b/libstdc++-v3/testsuite/20_util/endian/1.cc @@ -0,0 +1,36 @@ +// Copyright (C) 2017 Free Software Foundation, Inc. +// +// This file is part of the GNU ISO C++ Library. This library is free +// software; you can redistribute it and/or modify it under the +// terms of the GNU General Public License as published by the +// Free Software Foundation; either version 3, or (at your option) +// any later version. + +// This library is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License along +// with this library; see the file COPYING3. If not see +// <http://www.gnu.org/licenses/>. + +// { dg-options "-std=gnu++2a" } +// { dg-do compile { target c++2a } } + +#include <type_traits> + +static_assert( std::is_enum_v<std::endian> ); +static_assert( std::endian::little != std::endian::big ); +static_assert( std::endian::native == std::endian::big + || std::endian::native == std::endian::little ); + +namespace gnu { + int little, big, native; +} + +using namespace std; +using namespace gnu; + +// std::endian is a scoped-enum so these should refer to gnu::native etc. +int test = little + big + native;