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 // weak_ptr(const weak_ptr& r); 15 // weak_ptr(weak_ptr &&r) 16 17 #include <memory> 18 #include <type_traits> 19 #include <cassert> 20 21 struct B 22 { 23 static int count; 24 25 B() {++count;} 26 B(const B&) {++count;} 27 virtual ~B() {--count;} 28 }; 29 30 int B::count = 0; 31 32 struct A 33 : public B 34 { 35 static int count; 36 37 A() {++count;} 38 A(const A&) {++count;} 39 ~A() {--count;} 40 }; 41 42 int A::count = 0; 43 44 struct C 45 { 46 static int count; 47 48 C() {++count;} 49 C(const C&) {++count;} 50 virtual ~C() {--count;} 51 }; 52 53 int C::count = 0; 54 55 template <class T> 56 std::weak_ptr<T> source (std::shared_ptr<T> p) { return std::weak_ptr<T>(p); } 57 58 template <class T> 59 void sink (std::weak_ptr<T> &&) {} 60 61 int main() 62 { 63 { 64 const std::shared_ptr<A> ps(new A); 65 const std::weak_ptr<A> pA(ps); 66 assert(pA.use_count() == 1); 67 assert(B::count == 1); 68 assert(A::count == 1); 69 { 70 std::weak_ptr<A> pB(pA); 71 assert(B::count == 1); 72 assert(A::count == 1); 73 assert(pB.use_count() == 1); 74 assert(pA.use_count() == 1); 75 } 76 assert(pA.use_count() == 1); 77 assert(B::count == 1); 78 assert(A::count == 1); 79 } 80 assert(B::count == 0); 81 assert(A::count == 0); 82 { 83 std::weak_ptr<A> pA; 84 assert(pA.use_count() == 0); 85 assert(B::count == 0); 86 assert(A::count == 0); 87 { 88 std::weak_ptr<A> pB(pA); 89 assert(B::count == 0); 90 assert(A::count == 0); 91 assert(pB.use_count() == 0); 92 assert(pA.use_count() == 0); 93 } 94 assert(pA.use_count() == 0); 95 assert(B::count == 0); 96 assert(A::count == 0); 97 } 98 assert(B::count == 0); 99 assert(A::count == 0); 100 101 { 102 std::shared_ptr<A> ps(new A); 103 std::weak_ptr<A> pA = source(ps); 104 assert(pA.use_count() == 1); 105 assert(A::count == 1); 106 sink(std::move(pA)); // kill off the weak pointer 107 } 108 assert(B::count == 0); 109 assert(A::count == 0); 110 } 111
