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-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef _LIBCPP___CONCEPTS_RELATION_H
10#define _LIBCPP___CONCEPTS_RELATION_H
11
12#include <__concepts/predicate.h>
13#include <__config>
14
15#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
16# pragma GCC system_header
17#endif
18
19_LIBCPP_BEGIN_NAMESPACE_STD
20
21#if _LIBCPP_STD_VER >= 20
22
23// [concept.relation]
24
25template <class _Rp, class _Tp, class _Up>
26concept relation =
27 predicate<_Rp, _Tp, _Tp> && predicate<_Rp, _Up, _Up> && predicate<_Rp, _Tp, _Up> && predicate<_Rp, _Up, _Tp>;
28
29// [concept.equiv]
30
31template <class _Rp, class _Tp, class _Up>
32concept equivalence_relation = relation<_Rp, _Tp, _Up>;
33
34// [concept.strictweakorder]
35
36template <class _Rp, class _Tp, class _Up>
37concept strict_weak_order = relation<_Rp, _Tp, _Up>;
38
39#endif // _LIBCPP_STD_VER >= 20
40
41_LIBCPP_END_NAMESPACE_STD
42
43#endif // _LIBCPP___CONCEPTS_RELATION_H
44