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 // weak_ptr 13 14 // template<class Y> weak_ptr& operator=(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 int main() 44 { 45 { 46 const std::shared_ptr<A> pA(new A); 47 { 48 std::weak_ptr<B> pB; 49 pB = pA; 50 assert(B::count == 1); 51 assert(A::count == 1); 52 assert(pB.use_count() == 1); 53 assert(pA.use_count() == 1); 54 } 55 assert(pA.use_count() == 1); 56 assert(B::count == 1); 57 assert(A::count == 1); 58 } 59 assert(B::count == 0); 60 assert(A::count == 0); 61 } 62
