mirror of
https://github.com/jart/cosmopolitan.git
synced 2025-02-16 03:07:54 +00:00
57 lines
1.4 KiB
C++
57 lines
1.4 KiB
C++
// -*- C++ -*-
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef _LIBCPP___FUNCTIONAL_IDENTITY_H
|
|
#define _LIBCPP___FUNCTIONAL_IDENTITY_H
|
|
|
|
#include <__config>
|
|
#include <__type_traits/integral_constant.h>
|
|
#include <__utility/forward.h>
|
|
|
|
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
|
|
# pragma GCC system_header
|
|
#endif
|
|
|
|
_LIBCPP_BEGIN_NAMESPACE_STD
|
|
|
|
template <class _Tp>
|
|
struct __is_identity : false_type {};
|
|
|
|
struct __identity {
|
|
template <class _Tp>
|
|
_LIBCPP_NODISCARD _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR _Tp&& operator()(_Tp&& __t) const _NOEXCEPT {
|
|
return std::forward<_Tp>(__t);
|
|
}
|
|
|
|
using is_transparent = void;
|
|
};
|
|
|
|
template <>
|
|
struct __is_identity<__identity> : true_type {};
|
|
|
|
#if _LIBCPP_STD_VER >= 20
|
|
|
|
struct identity {
|
|
template<class _Tp>
|
|
_LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr _Tp&& operator()(_Tp&& __t) const noexcept
|
|
{
|
|
return _VSTD::forward<_Tp>(__t);
|
|
}
|
|
|
|
using is_transparent = void;
|
|
};
|
|
|
|
template <>
|
|
struct __is_identity<identity> : true_type {};
|
|
|
|
#endif // _LIBCPP_STD_VER >= 20
|
|
|
|
_LIBCPP_END_NAMESPACE_STD
|
|
|
|
#endif // _LIBCPP___FUNCTIONAL_IDENTITY_H
|