llvm-project/libcxx/include/__compare/compare_three_way_result.h

44 lines
1.4 KiB
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___COMPARE_COMPARE_THREE_WAY_RESULT_H
#define _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
#include <__config>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
template<class, class, class>
struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result { };
template<class _Tp, class _Up>
struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result<_Tp, _Up, decltype(
declval<__make_const_lvalue_ref<_Tp>>() <=> declval<__make_const_lvalue_ref<_Up>>(), void()
)> {
using type = decltype(declval<__make_const_lvalue_ref<_Tp>>() <=> declval<__make_const_lvalue_ref<_Up>>());
};
template<class _Tp, class _Up = _Tp>
struct _LIBCPP_TEMPLATE_VIS compare_three_way_result : __compare_three_way_result<_Tp, _Up, void> { };
template<class _Tp, class _Up = _Tp>
using compare_three_way_result_t = typename compare_three_way_result<_Tp, _Up>::type;
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H