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// <utility>
10
11// template<class T>
12// requires MoveAssignable<T> && MoveConstructible<T>
13// void
14// swap(T& a, T& b);
15
16#include <cassert>
17#include <memory>
18#include <type_traits>
19#include <utility>
20
21#include "test_macros.h"
22
23#if TEST_STD_VER >= 11
24struct CopyOnly {
25 CopyOnly() {}
26 CopyOnly(CopyOnly const&) noexcept {}
27 CopyOnly& operator=(CopyOnly const&) { return *this; }
28};
29
30struct MoveOnly {
31 MoveOnly() {}
32 MoveOnly(MoveOnly&&) {}
33 MoveOnly& operator=(MoveOnly&&) noexcept { return *this; }
34};
35
36struct NoexceptMoveOnly {
37 NoexceptMoveOnly() {}
38 NoexceptMoveOnly(NoexceptMoveOnly&&) noexcept {}
39 NoexceptMoveOnly& operator=(NoexceptMoveOnly&&) noexcept { return *this; }
40};
41
42struct NotMoveConstructible {
43 NotMoveConstructible& operator=(NotMoveConstructible&&) { return *this; }
44private:
45 NotMoveConstructible(NotMoveConstructible&&);
46};
47
48struct NotMoveAssignable {
49 NotMoveAssignable(NotMoveAssignable&&);
50private:
51 NotMoveAssignable& operator=(NotMoveAssignable&&);
52};
53
54template <class Tp>
55auto can_swap_test(int) -> decltype(std::swap(std::declval<Tp>(), std::declval<Tp>()));
56
57template <class Tp>
58auto can_swap_test(...) -> std::false_type;
59
60template <class Tp>
61constexpr bool can_swap() {
62 return std::is_same<decltype(can_swap_test<Tp>(0)), void>::value;
63}
64#endif
65
66#if TEST_STD_VER > 17
67constexpr bool test_swap_constexpr()
68{
69 int i = 1;
70 int j = 2;
71 std::swap(i, j);
72 return i == 2 && j == 1;
73}
74#endif // TEST_STD_VER > 17
75
76int main(int, char**)
77{
78
79 {
80 int i = 1;
81 int j = 2;
82 std::swap(a&: i, b&: j);
83 assert(i == 2);
84 assert(j == 1);
85 }
86#if TEST_STD_VER >= 11
87 {
88
89 std::unique_ptr<int> i(new int(1));
90 std::unique_ptr<int> j(new int(2));
91 std::swap(i, j);
92 assert(*i == 2);
93 assert(*j == 1);
94
95 }
96 {
97 // test that the swap
98 static_assert(can_swap<CopyOnly&>(), "");
99 static_assert(can_swap<MoveOnly&>(), "");
100 static_assert(can_swap<NoexceptMoveOnly&>(), "");
101
102 static_assert(!can_swap<NotMoveConstructible&>(), "");
103 static_assert(!can_swap<NotMoveAssignable&>(), "");
104
105 CopyOnly c;
106 MoveOnly m;
107 NoexceptMoveOnly nm;
108 static_assert(!noexcept(std::swap(c, c)), "");
109 static_assert(!noexcept(std::swap(m, m)), "");
110 static_assert(noexcept(std::swap(nm, nm)), "");
111 }
112#endif
113
114#if TEST_STD_VER > 17
115 static_assert(test_swap_constexpr());
116#endif // TEST_STD_VER > 17
117
118 return 0;
119}
120

source code of libcxx/test/std/utilities/utility/utility.swap/swap.pass.cpp