| //===----------------------------------------------------------------------===// |
| // |
| // 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___UTILITY_EXCHANGE_H |
| #define _LIBCPP___UTILITY_EXCHANGE_H |
| |
| #include <__config> |
| #include <__type_traits/is_nothrow_assignable.h> |
| #include <__type_traits/is_nothrow_move_constructible.h> |
| #include <__utility/forward.h> |
| #include <__utility/move.h> |
| |
| #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) |
| # pragma GCC system_header |
| #endif |
| |
| _LIBCPP_BEGIN_NAMESPACE_STD |
| |
| #if _LIBCPP_STD_VER > 11 |
| template<class _T1, class _T2 = _T1> |
| inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX20 |
| _T1 exchange(_T1& __obj, _T2&& __new_value) |
| noexcept(is_nothrow_move_constructible<_T1>::value && is_nothrow_assignable<_T1&, _T2>::value) |
| { |
| _T1 __old_value = _VSTD::move(__obj); |
| __obj = _VSTD::forward<_T2>(__new_value); |
| return __old_value; |
| } |
| #endif // _LIBCPP_STD_VER > 11 |
| |
| _LIBCPP_END_NAMESPACE_STD |
| |
| #endif // _LIBCPP___UTILITY_EXCHANGE_H |
