1 //===----------------------------------------------------------------------===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef _LIBCPP___TYPE_TRAITS_IS_CONST_H 10 #define _LIBCPP___TYPE_TRAITS_IS_CONST_H 11 12 #include <__config> 13 #include <__type_traits/integral_constant.h> 14 15 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 16 # pragma GCC system_header 17 #endif 18 19 _LIBCPP_BEGIN_NAMESPACE_STD 20 21 #if __has_builtin(__is_const) 22 23 template <class _Tp> 24 struct _LIBCPP_TEMPLATE_VIS is_const : _BoolConstant<__is_const(_Tp)> {}; 25 26 # if _LIBCPP_STD_VER >= 17 27 template <class _Tp> 28 inline constexpr bool is_const_v = __is_const(_Tp); 29 # endif 30 31 #else 32 33 template <class _Tp> 34 struct _LIBCPP_TEMPLATE_VIS is_const : public false_type {}; 35 template <class _Tp> 36 struct _LIBCPP_TEMPLATE_VIS is_const<_Tp const> : public true_type {}; 37 38 # if _LIBCPP_STD_VER >= 17 39 template <class _Tp> 40 inline constexpr bool is_const_v = is_const<_Tp>::value; 41 # endif 42 43 #endif // __has_builtin(__is_const) 44 45 _LIBCPP_END_NAMESPACE_STD 46 47 #endif // _LIBCPP___TYPE_TRAITS_IS_CONST_H 48