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 // bool expired() const;
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         std::weak_ptr<A> wp;
35         assert(wp.use_count() == 0);
36         assert(wp.expired() == (wp.use_count() == 0));
37     }
38     {
39         std::shared_ptr<A> sp0(new A);
40         std::weak_ptr<A> wp(sp0);
41         assert(wp.use_count() == 1);
42         assert(wp.expired() == (wp.use_count() == 0));
43         sp0.reset();
44         assert(wp.use_count() == 0);
45         assert(wp.expired() == (wp.use_count() == 0));
46     }
47 
48   return 0;
49 }
50