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 // template<class Y> weak_ptr(const shared_ptr<Y>& r);
14 
15 #include <memory>
16 #include <type_traits>
17 #include <cassert>
18 
19 #include "test_macros.h"
20 
21 struct B
22 {
23     static int count;
24 
BB25     B() {++count;}
BB26     B(const B&) {++count;}
~BB27     virtual ~B() {--count;}
28 };
29 
30 int B::count = 0;
31 
32 struct A
33     : public B
34 {
35     static int count;
36 
AA37     A() {++count;}
AA38     A(const A& other) : B(other) {++count;}
~AA39     ~A() {--count;}
40 };
41 
42 int A::count = 0;
43 
44 struct C
45 {
46     static int count;
47 
CC48     C() {++count;}
CC49     C(const C&) {++count;}
~CC50     virtual ~C() {--count;}
51 };
52 
53 int C::count = 0;
54 
main(int,char **)55 int main(int, char**)
56 {
57     static_assert(( std::is_convertible<std::shared_ptr<A>, std::weak_ptr<B> >::value), "");
58     static_assert((!std::is_convertible<std::weak_ptr<B>, std::shared_ptr<A> >::value), "");
59     static_assert((!std::is_convertible<std::shared_ptr<A>, std::weak_ptr<C> >::value), "");
60     {
61         const std::shared_ptr<A> pA(new A);
62         assert(pA.use_count() == 1);
63         assert(B::count == 1);
64         assert(A::count == 1);
65         {
66             std::weak_ptr<B> pB(pA);
67             assert(B::count == 1);
68             assert(A::count == 1);
69             assert(pB.use_count() == 1);
70             assert(pA.use_count() == 1);
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::weak_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         }
90         assert(pA.use_count() == 0);
91         assert(B::count == 0);
92         assert(A::count == 0);
93     }
94     assert(B::count == 0);
95     assert(A::count == 0);
96 
97 #if TEST_STD_VER > 14
98     {
99         std::shared_ptr<A[]> p1(new A[8]);
100         assert(p1.use_count() == 1);
101         assert(A::count == 8);
102         {
103             std::weak_ptr<const A[]> p2(p1);
104             assert(A::count == 8);
105             assert(p2.use_count() == 1);
106             assert(p1.use_count() == 1);
107         }
108         assert(p1.use_count() == 1);
109         assert(A::count == 8);
110     }
111     assert(A::count == 0);
112 #endif
113 
114   return 0;
115 }
116