[PATCH] Define std::endian for C++2a (P0463R1)
Jonathan Wakely
jwakely@redhat.com
Fri Nov 3 15:46:00 GMT 2017
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.
-------------- next part --------------
commit ad69c5875cdefc5c699b50975ee6016a424d450b
Author: Jonathan Wakely <jwakely@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;
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