swap.pass.cpp revision f5256e16dfc425c1d466f6308d4026d529ce9e0b 
1//===----------------------------------------------------------------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10// <memory>
11
12// weak_ptr
13
14// template<class T> void swap(weak_ptr<T>& a, weak_ptr<T>& b)
15
16#include <memory>
17#include <cassert>
18
19struct A
20{
21    static int count;
22
23    A() {++count;}
24    A(const A&) {++count;}
25    ~A() {--count;}
26};
27
28int A::count = 0;
29
30int main()
31{
32    {
33        A* ptr1 = new A;
34        A* ptr2 = new A;
35        std::shared_ptr<A> p1(ptr1);
36        std::weak_ptr<A> w1(p1);
37        {
38            std::shared_ptr<A> p2(ptr2);
39            std::weak_ptr<A> w2(p2);
40            swap(w1, w2);
41            assert(w1.use_count() == 1);
42            assert(w1.lock().get() == ptr2);
43            assert(w2.use_count() == 1);
44            assert(w2.lock().get() == ptr1);
45            assert(A::count == 2);
46        }
47    }
48    assert(A::count == 0);
49}
50