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 // shared_ptr<T> lock() 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         std::shared_ptr<A> sp = wp.lock();
36         assert(sp.use_count() == 0);
37         assert(sp.get() == 0);
38         assert(A::count == 0);
39     }
40     {
41         std::shared_ptr<A> sp0(new A);
42         std::weak_ptr<A> wp(sp0);
43         std::shared_ptr<A> sp = wp.lock();
44         assert(sp.use_count() == 2);
45         assert(sp.get() == sp0.get());
46         assert(A::count == 1);
47     }
48     assert(A::count == 0);
49     {
50         std::shared_ptr<A> sp0(new A);
51         std::weak_ptr<A> wp(sp0);
52         sp0.reset();
53         std::shared_ptr<A> sp = wp.lock();
54         assert(sp.use_count() == 0);
55         assert(sp.get() == 0);
56         assert(A::count == 0);
57     }
58     assert(A::count == 0);
59 
60   return 0;
61 }
62