//===----------------------------------------------------------------------===// // // 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_SYNTH_THREE_WAY_H #define _LIBCPP___COMPARE_SYNTH_THREE_WAY_H #include <__compare/ordering.h> #include <__compare/three_way_comparable.h> #include <__concepts/boolean_testable.h> #include <__config> #include <__utility/declval.h> #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) # pragma GCC system_header #endif _LIBCPP_BEGIN_NAMESPACE_STD #if _LIBCPP_STD_VER > 17 // [expos.only.func] _LIBCPP_HIDE_FROM_ABI inline constexpr auto __synth_three_way = [](const _Tp& __t, const _Up& __u) requires requires { { __t < __u } -> __boolean_testable; { __u < __t } -> __boolean_testable; } { if constexpr (three_way_comparable_with<_Tp, _Up>) { return __t <=> __u; } else { if (__t < __u) return weak_ordering::less; if (__u < __t) return weak_ordering::greater; return weak_ordering::equivalent; } }; template using __synth_three_way_result = decltype(std::__synth_three_way(std::declval<_Tp&>(), std::declval<_Up&>())); #endif // _LIBCPP_STD_VER > 17 _LIBCPP_END_NAMESPACE_STD #endif // _LIBCPP___COMPARE_SYNTH_THREE_WAY_H