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___UTILITY_AS_CONST_H
10#define _LIBCPP___UTILITY_AS_CONST_H
11
12#include <__config>
13#include <__type_traits/add_const.h>
14#include <__utility/forward.h>
15#include <__utility/move.h>
16
17#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
18# pragma GCC system_header
19#endif
20
21_LIBCPP_BEGIN_NAMESPACE_STD
22
23#if _LIBCPP_STD_VER >= 17
24template <class _Tp>
25[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr add_const_t<_Tp>& as_const(_Tp& __t) noexcept {
26 return __t;
27}
28
29template <class _Tp>
30void as_const(const _Tp&&) = delete;
31#endif
32
33_LIBCPP_END_NAMESPACE_STD
34
35#endif // _LIBCPP___UTILITY_AS_CONST_H
36