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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-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H10#define _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H11 12#include <__config>13#include <__type_traits/make_const_lvalue_ref.h>14#include <__utility/declval.h>15 16#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)17# pragma GCC system_header18#endif19 20_LIBCPP_BEGIN_NAMESPACE_STD21 22#if _LIBCPP_STD_VER >= 2023 24template <class, class, class>25struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result {};26 27template <class _Tp, class _Up>28struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result<29 _Tp,30 _Up,31 decltype(std::declval<__make_const_lvalue_ref<_Tp>>() <=> std::declval<__make_const_lvalue_ref<_Up>>(), void())> {32 using type _LIBCPP_NODEBUG =33 decltype(std::declval<__make_const_lvalue_ref<_Tp>>() <=> std::declval<__make_const_lvalue_ref<_Up>>());34};35 36template <class _Tp, class _Up = _Tp>37struct _LIBCPP_NO_SPECIALIZATIONS compare_three_way_result : __compare_three_way_result<_Tp, _Up, void> {};38 39template <class _Tp, class _Up = _Tp>40using compare_three_way_result_t = typename compare_three_way_result<_Tp, _Up>::type;41 42#endif // _LIBCPP_STD_VER >= 2043 44_LIBCPP_END_NAMESPACE_STD45 46#endif // _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H47