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 // <array>
10
11 // template <class T, size_t N> void swap(array<T,N>& x, array<T,N>& y);
12
13 #include <array>
14 #include <cassert>
15
16 #include "test_macros.h"
17 // std::array is explicitly allowed to be initialized with A a = { init-list };.
18 // Disable the missing braces warning for this reason.
19 #include "disable_missing_braces_warning.h"
20
21 struct NonSwappable {
NonSwappableNonSwappable22 NonSwappable() {}
23 private:
24 NonSwappable(NonSwappable const&);
25 NonSwappable& operator=(NonSwappable const&);
26 };
27
28 template <class Tp>
29 decltype(swap(std::declval<Tp>(), std::declval<Tp>()))
30 can_swap_imp(int);
31
32 template <class Tp>
33 std::false_type can_swap_imp(...);
34
35 template <class Tp>
36 struct can_swap : std::is_same<decltype(can_swap_imp<Tp>(0)), void> {};
37
main(int,char **)38 int main(int, char**)
39 {
40 {
41 typedef double T;
42 typedef std::array<T, 3> C;
43 C c1 = {1, 2, 3.5};
44 C c2 = {4, 5, 6.5};
45 swap(c1, c2);
46 assert(c1.size() == 3);
47 assert(c1[0] == 4);
48 assert(c1[1] == 5);
49 assert(c1[2] == 6.5);
50 assert(c2.size() == 3);
51 assert(c2[0] == 1);
52 assert(c2[1] == 2);
53 assert(c2[2] == 3.5);
54 }
55 {
56 typedef double T;
57 typedef std::array<T, 0> C;
58 C c1 = {};
59 C c2 = {};
60 swap(c1, c2);
61 assert(c1.size() == 0);
62 assert(c2.size() == 0);
63 }
64 {
65 typedef NonSwappable T;
66 typedef std::array<T, 0> C0;
67 static_assert(can_swap<C0&>::value, "");
68 C0 l = {};
69 C0 r = {};
70 swap(l, r);
71 #if TEST_STD_VER >= 11
72 static_assert(noexcept(swap(l, r)), "");
73 #endif
74 }
75 #if TEST_STD_VER >= 11
76 {
77 // NonSwappable is still considered swappable in C++03 because there
78 // is no access control SFINAE.
79 typedef NonSwappable T;
80 typedef std::array<T, 42> C1;
81 static_assert(!can_swap<C1&>::value, "");
82 }
83 #endif
84
85 return 0;
86 }
87