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