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// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20, c++23
10
11// <functional>
12
13// class reference_wrapper
14
15// [refwrap.comparisons], comparisons
16
17// friend constexpr auto operator<=>(reference_wrapper, reference_wrapper<const T>); // Since C++26
18
19#include <cassert>
20#include <concepts>
21#include <functional>
22
23#include "test_comparisons.h"
24#include "test_macros.h"
25
26#include "helper_concepts.h"
27#include "helper_types.h"
28
29// Test SFINAE.
30
31static_assert(std::three_way_comparable_with<std::reference_wrapper<StrongOrder>, const StrongOrder>);
32static_assert(std::three_way_comparable_with<std::reference_wrapper<WeakOrder>, const WeakOrder>);
33static_assert(std::three_way_comparable_with<std::reference_wrapper<PartialOrder>, const PartialOrder>);
34
35static_assert(!std::three_way_comparable_with<std::reference_wrapper<StrongOrder>, const NonComparable>);
36static_assert(!std::three_way_comparable_with<std::reference_wrapper<WeakOrder>, const NonComparable>);
37static_assert(!std::three_way_comparable_with<std::reference_wrapper<PartialOrder>, const NonComparable>);
38
39// Test comparisons.
40
41template <typename T, typename Order>
42constexpr void test() {
43 T t{47};
44
45 T bigger{94};
46 T smaller{82};
47
48 T unordered{std::numeric_limits<int>::min()};
49
50 // Identical contents
51 {
52 std::reference_wrapper<T> rw1{t};
53 std::reference_wrapper<const T> rw2{t};
54 assert(testOrder(rw1, rw2, Order::equivalent));
55 }
56 // Less
57 {
58 std::reference_wrapper<T> rw1{smaller};
59 std::reference_wrapper<const T> rw2{bigger};
60 assert(testOrder(rw1, rw2, Order::less));
61 }
62 // Greater
63 {
64 std::reference_wrapper<T> rw1{bigger};
65 std::reference_wrapper<const T> rw2{smaller};
66 assert(testOrder(rw1, rw2, Order::greater));
67 }
68 // Unordered
69 if constexpr (std::same_as<T, PartialOrder>) {
70 std::reference_wrapper<T> rw1{bigger};
71 std::reference_wrapper<const T> rw2{unordered};
72 assert(testOrder(rw1, rw2, Order::unordered));
73 }
74}
75
76constexpr bool test() {
77 test<int, std::strong_ordering>();
78 test<StrongOrder, std::strong_ordering>();
79 test<int, std::weak_ordering>();
80 test<WeakOrder, std::weak_ordering>();
81 test<int, std::partial_ordering>();
82 test<PartialOrder, std::partial_ordering>();
83
84 // `LessAndEqComp` does not have `operator<=>`. Ordering is synthesized based on `operator<`
85 test<LessAndEqComp, std::weak_ordering>();
86
87 return true;
88}
89
90int main(int, char**) {
91 test();
92 static_assert(test());
93
94 return 0;
95}
96

source code of libcxx/test/std/utilities/function.objects/refwrap/refwrap.comparissons/compare.three_way.refwrap.refwrap_const.pass.cpp