1 //===----------------------------------------------------------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 // <memory>
11 
12 // shared_ptr
13 
14 // template<class Y> shared_ptr& operator=(shared_ptr<Y>&& r);
15 
16 #include <memory>
17 #include <type_traits>
18 #include <cassert>
19 
20 struct B
21 {
22     static int count;
23 
24     B() {++count;}
25     B(const B&) {++count;}
26     virtual ~B() {--count;}
27 };
28 
29 int B::count = 0;
30 
31 struct A
32     : public B
33 {
34     static int count;
35 
36     A() {++count;}
37     A(const A&) {++count;}
38     ~A() {--count;}
39 };
40 
41 int A::count = 0;
42 
43 int main()
44 {
45 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
46     {
47         std::shared_ptr<A> pA(new A);
48         A* ptrA = pA.get();
49         {
50             std::shared_ptr<B> pB(new B);
51             pB = std::move(pA);
52             assert(B::count == 1);
53             assert(A::count == 1);
54             assert(pB.use_count() == 1);
55             assert(pA.use_count() == 0);
56             assert(pA.get() == 0);
57             assert(pB.get() == ptrA);
58         }
59         assert(pA.use_count() == 0);
60         assert(B::count == 0);
61         assert(A::count == 0);
62     }
63     assert(B::count == 0);
64     assert(A::count == 0);
65     {
66         std::shared_ptr<A> pA;
67         A* ptrA = pA.get();
68         {
69             std::shared_ptr<B> pB(new B);
70             pB = std::move(pA);
71             assert(B::count == 0);
72             assert(A::count == 0);
73             assert(pB.use_count() == 0);
74             assert(pA.use_count() == 0);
75             assert(pA.get() == 0);
76             assert(pB.get() == ptrA);
77         }
78         assert(pA.use_count() == 0);
79         assert(B::count == 0);
80         assert(A::count == 0);
81     }
82     assert(B::count == 0);
83     assert(A::count == 0);
84     {
85         std::shared_ptr<A> pA(new A);
86         A* ptrA = pA.get();
87         {
88             std::shared_ptr<B> pB;
89             pB = std::move(pA);
90             assert(B::count == 1);
91             assert(A::count == 1);
92             assert(pB.use_count() == 1);
93             assert(pA.use_count() == 0);
94             assert(pA.get() == 0);
95             assert(pB.get() == ptrA);
96         }
97         assert(pA.use_count() == 0);
98         assert(B::count == 0);
99         assert(A::count == 0);
100     }
101     assert(B::count == 0);
102     assert(A::count == 0);
103     {
104         std::shared_ptr<A> pA;
105         A* ptrA = pA.get();
106         {
107             std::shared_ptr<B> pB;
108             pB = std::move(pA);
109             assert(B::count == 0);
110             assert(A::count == 0);
111             assert(pB.use_count() == 0);
112             assert(pA.use_count() == 0);
113             assert(pA.get() == 0);
114             assert(pB.get() == ptrA);
115         }
116         assert(pA.use_count() == 0);
117         assert(B::count == 0);
118         assert(A::count == 0);
119     }
120     assert(B::count == 0);
121     assert(A::count == 0);
122 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
123 }
124