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(const 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 struct C
44 {
45     static int count;
46 
47     C() {++count;}
48     C(const C&) {++count;}
49     virtual ~C() {--count;}
50 };
51 
52 int C::count = 0;
53 
54 int main()
55 {
56     static_assert(( std::is_convertible<std::shared_ptr<A>, std::shared_ptr<B> >::value), "");
57     static_assert((!std::is_convertible<std::shared_ptr<B>, std::shared_ptr<A> >::value), "");
58     static_assert((!std::is_convertible<std::shared_ptr<A>, std::shared_ptr<C> >::value), "");
59     {
60         const std::shared_ptr<A> pA(new A);
61         assert(pA.use_count() == 1);
62         assert(B::count == 1);
63         assert(A::count == 1);
64         {
65             std::shared_ptr<B> pB(pA);
66             assert(B::count == 1);
67             assert(A::count == 1);
68             assert(pB.use_count() == 2);
69             assert(pA.use_count() == 2);
70             assert(pA.get() == pB.get());
71         }
72         assert(pA.use_count() == 1);
73         assert(B::count == 1);
74         assert(A::count == 1);
75     }
76     assert(B::count == 0);
77     assert(A::count == 0);
78     {
79         std::shared_ptr<A> pA;
80         assert(pA.use_count() == 0);
81         assert(B::count == 0);
82         assert(A::count == 0);
83         {
84             std::shared_ptr<B> pB(pA);
85             assert(B::count == 0);
86             assert(A::count == 0);
87             assert(pB.use_count() == 0);
88             assert(pA.use_count() == 0);
89             assert(pA.get() == pB.get());
90         }
91         assert(pA.use_count() == 0);
92         assert(B::count == 0);
93         assert(A::count == 0);
94     }
95     assert(B::count == 0);
96     assert(A::count == 0);
97 }
98