1*fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 2*fe6060f1SDimitry Andric // 3*fe6060f1SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*fe6060f1SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*fe6060f1SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*fe6060f1SDimitry Andric // 7*fe6060f1SDimitry Andric //===----------------------------------------------------------------------===// 8*fe6060f1SDimitry Andric 9*fe6060f1SDimitry Andric #ifndef _LIBCPP___UTILITY_EXCHANGE_H 10*fe6060f1SDimitry Andric #define _LIBCPP___UTILITY_EXCHANGE_H 11*fe6060f1SDimitry Andric 12*fe6060f1SDimitry Andric #include <__config> 13*fe6060f1SDimitry Andric #include <__utility/forward.h> 14*fe6060f1SDimitry Andric #include <__utility/move.h> 15*fe6060f1SDimitry Andric 16*fe6060f1SDimitry Andric #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 17*fe6060f1SDimitry Andric #pragma GCC system_header 18*fe6060f1SDimitry Andric #endif 19*fe6060f1SDimitry Andric 20*fe6060f1SDimitry Andric _LIBCPP_PUSH_MACROS 21*fe6060f1SDimitry Andric #include <__undef_macros> 22*fe6060f1SDimitry Andric 23*fe6060f1SDimitry Andric _LIBCPP_BEGIN_NAMESPACE_STD 24*fe6060f1SDimitry Andric 25*fe6060f1SDimitry Andric #if _LIBCPP_STD_VER > 11 26*fe6060f1SDimitry Andric template<class _T1, class _T2 = _T1> 27*fe6060f1SDimitry Andric inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 28*fe6060f1SDimitry Andric _T1 exchange(_T1& __obj, _T2 && __new_value) 29*fe6060f1SDimitry Andric { 30*fe6060f1SDimitry Andric _T1 __old_value = _VSTD::move(__obj); 31*fe6060f1SDimitry Andric __obj = _VSTD::forward<_T2>(__new_value); 32*fe6060f1SDimitry Andric return __old_value; 33*fe6060f1SDimitry Andric } 34*fe6060f1SDimitry Andric #endif // _LIBCPP_STD_VER > 11 35*fe6060f1SDimitry Andric 36*fe6060f1SDimitry Andric _LIBCPP_END_NAMESPACE_STD 37*fe6060f1SDimitry Andric 38*fe6060f1SDimitry Andric _LIBCPP_POP_MACROS 39*fe6060f1SDimitry Andric 40*fe6060f1SDimitry Andric #endif // _LIBCPP___UTILITY_EXCHANGE_H 41