1 //===----------------------------------------------------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
14 // template<class Y> weak_ptr(const weak_ptr<Y>& r);
15 // template<class Y> weak_ptr(weak_ptr<Y> &&r);
18 #include <type_traits>
26 B(const B&) {++count;}
27 virtual ~B() {--count;}
38 A(const A&) {++count;}
49 C(const C&) {++count;}
50 virtual ~C() {--count;}
56 std::weak_ptr<T> source (std::shared_ptr<T> p) { return std::weak_ptr<T>(p); }
59 void sink (std::weak_ptr<T> &&) {}
63 static_assert(( std::is_convertible<std::weak_ptr<A>, std::weak_ptr<B> >::value), "");
64 static_assert((!std::is_convertible<std::weak_ptr<B>, std::weak_ptr<A> >::value), "");
65 static_assert((!std::is_convertible<std::weak_ptr<A>, std::weak_ptr<C> >::value), "");
67 const std::weak_ptr<A> pA(std::shared_ptr<A>(new A));
68 assert(pA.use_count() == 0);
69 assert(B::count == 0);
70 assert(A::count == 0);
72 std::weak_ptr<B> pB(pA);
73 assert(B::count == 0);
74 assert(A::count == 0);
75 assert(pB.use_count() == 0);
76 assert(pA.use_count() == 0);
78 assert(pA.use_count() == 0);
79 assert(B::count == 0);
80 assert(A::count == 0);
82 assert(B::count == 0);
83 assert(A::count == 0);
86 assert(pA.use_count() == 0);
87 assert(B::count == 0);
88 assert(A::count == 0);
90 std::weak_ptr<B> pB(pA);
91 assert(B::count == 0);
92 assert(A::count == 0);
93 assert(pB.use_count() == 0);
94 assert(pA.use_count() == 0);
96 assert(pA.use_count() == 0);
97 assert(B::count == 0);
98 assert(A::count == 0);
100 assert(B::count == 0);
101 assert(A::count == 0);
104 std::shared_ptr<A> ps(new A);
105 std::weak_ptr<A> pA = source(ps);
106 std::weak_ptr<B> pB(std::move(pA));
107 assert(pB.use_count() == 1);
109 assert(B::count == 0);
110 assert(A::count == 0);