xref: /openbsd-src/gnu/llvm/libcxx/include/__compare/compare_three_way_result.h (revision 4bdff4bed0e3d54e55670334c7d0077db4170f86)
1*4bdff4beSrobert //===----------------------------------------------------------------------===//
2*4bdff4beSrobert //
3*4bdff4beSrobert // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4*4bdff4beSrobert // See https://llvm.org/LICENSE.txt for license information.
5*4bdff4beSrobert // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6*4bdff4beSrobert //
7*4bdff4beSrobert //===----------------------------------------------------------------------===//
8*4bdff4beSrobert 
9*4bdff4beSrobert #ifndef _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
10*4bdff4beSrobert #define _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
11*4bdff4beSrobert 
12*4bdff4beSrobert #include <__config>
13*4bdff4beSrobert #include <__type_traits/make_const_lvalue_ref.h>
14*4bdff4beSrobert #include <__utility/declval.h>
15*4bdff4beSrobert 
16*4bdff4beSrobert #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
17*4bdff4beSrobert #  pragma GCC system_header
18*4bdff4beSrobert #endif
19*4bdff4beSrobert 
20*4bdff4beSrobert _LIBCPP_BEGIN_NAMESPACE_STD
21*4bdff4beSrobert 
22*4bdff4beSrobert #if _LIBCPP_STD_VER > 17
23*4bdff4beSrobert 
24*4bdff4beSrobert template<class, class, class>
25*4bdff4beSrobert struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result { };
26*4bdff4beSrobert 
27*4bdff4beSrobert template<class _Tp, class _Up>
28*4bdff4beSrobert struct _LIBCPP_HIDE_FROM_ABI __compare_three_way_result<_Tp, _Up, decltype(
29*4bdff4beSrobert   std::declval<__make_const_lvalue_ref<_Tp>>() <=> std::declval<__make_const_lvalue_ref<_Up>>(), void()
30*4bdff4beSrobert )> {
31*4bdff4beSrobert     using type = decltype(std::declval<__make_const_lvalue_ref<_Tp>>() <=> std::declval<__make_const_lvalue_ref<_Up>>());
32*4bdff4beSrobert };
33*4bdff4beSrobert 
34*4bdff4beSrobert template<class _Tp, class _Up = _Tp>
35*4bdff4beSrobert struct _LIBCPP_TEMPLATE_VIS compare_three_way_result : __compare_three_way_result<_Tp, _Up, void> { };
36*4bdff4beSrobert 
37*4bdff4beSrobert template<class _Tp, class _Up = _Tp>
38*4bdff4beSrobert using compare_three_way_result_t = typename compare_three_way_result<_Tp, _Up>::type;
39*4bdff4beSrobert 
40*4bdff4beSrobert #endif // _LIBCPP_STD_VER > 17
41*4bdff4beSrobert 
42*4bdff4beSrobert _LIBCPP_END_NAMESPACE_STD
43*4bdff4beSrobert 
44*4bdff4beSrobert #endif // _LIBCPP___COMPARE_COMPARE_THREE_WAY_RESULT_H
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