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 // <memory>
10 
11 // weak_ptr
12 
13 // template<class T> void swap(weak_ptr<T>& a, weak_ptr<T>& b)
14 
15 #include <memory>
16 #include <cassert>
17 
18 #include "test_macros.h"
19 
20 struct A
21 {
22     static int count;
23 
AA24     A() {++count;}
AA25     A(const A&) {++count;}
~AA26     ~A() {--count;}
27 };
28 
29 int A::count = 0;
30 
main(int,char **)31 int main(int, char**)
32 {
33     {
34         A* ptr1 = new A;
35         A* ptr2 = new A;
36         std::shared_ptr<A> p1(ptr1);
37         std::weak_ptr<A> w1(p1);
38         {
39             std::shared_ptr<A> p2(ptr2);
40             std::weak_ptr<A> w2(p2);
41             swap(w1, w2);
42             assert(w1.use_count() == 1);
43             assert(w1.lock().get() == ptr2);
44             assert(w2.use_count() == 1);
45             assert(w2.lock().get() == ptr1);
46             assert(A::count == 2);
47         }
48     }
49     assert(A::count == 0);
50 
51   return 0;
52 }
53