1fe6060f1SDimitry Andric // -*- C++ -*- 2fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 3fe6060f1SDimitry Andric // 4fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 6fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7fe6060f1SDimitry Andric // 8fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 9fe6060f1SDimitry Andric 10fe6060f1SDimitry Andric #ifndef _LIBCPP___FUNCTIONAL_IDENTITY_H 11fe6060f1SDimitry Andric #define _LIBCPP___FUNCTIONAL_IDENTITY_H 12fe6060f1SDimitry Andric 13fe6060f1SDimitry Andric #include <__config> 14*81ad6265SDimitry Andric #include <__utility/forward.h> 15fe6060f1SDimitry Andric 16fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17fe6060f1SDimitry Andric # pragma GCC system_header 18fe6060f1SDimitry Andric #endif 19fe6060f1SDimitry Andric 20fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 21fe6060f1SDimitry Andric 22*81ad6265SDimitry Andric struct __identity { 23*81ad6265SDimitry Andric template <class _Tp> 24*81ad6265SDimitry Andric _LIBCPP_NODISCARD _LIBCPP_CONSTEXPR _Tp&& operator()(_Tp&& __t) const _NOEXCEPT { 25*81ad6265SDimitry Andric return std::forward<_Tp>(__t); 26*81ad6265SDimitry Andric } 27*81ad6265SDimitry Andric 28*81ad6265SDimitry Andric using is_transparent = void; 29*81ad6265SDimitry Andric }; 30*81ad6265SDimitry Andric 31fe6060f1SDimitry Andric #if _LIBCPP_STD_VER > 17 32fe6060f1SDimitry Andric 33fe6060f1SDimitry Andric struct identity { 34fe6060f1SDimitry Andric template<class _Tp> 35fe6060f1SDimitry Andric _LIBCPP_NODISCARD_EXT constexpr _Tp&& operator()(_Tp&& __t) const noexcept 36fe6060f1SDimitry Andric { 37fe6060f1SDimitry Andric return _VSTD::forward<_Tp>(__t); 38fe6060f1SDimitry Andric } 39fe6060f1SDimitry Andric 40fe6060f1SDimitry Andric using is_transparent = void; 41fe6060f1SDimitry Andric }; 42fe6060f1SDimitry Andric #endif // _LIBCPP_STD_VER > 17 43fe6060f1SDimitry Andric 44fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 45fe6060f1SDimitry Andric 46fe6060f1SDimitry Andric #endif // _LIBCPP___FUNCTIONAL_IDENTITY_H 47