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 // shared_ptr<T> lock() const; 15 16 #include <memory> 17 #include <cassert> 18 19 struct A 20 { 21 static int count; 22 23 A() {++count;} 24 A(const A&) {++count;} 25 ~A() {--count;} 26 }; 27 28 int A::count = 0; 29 30 int main() 31 { 32 { 33 std::weak_ptr<A> wp; 34 std::shared_ptr<A> sp = wp.lock(); 35 assert(sp.use_count() == 0); 36 assert(sp.get() == 0); 37 assert(A::count == 0); 38 } 39 { 40 std::shared_ptr<A> sp0(new A); 41 std::weak_ptr<A> wp(sp0); 42 std::shared_ptr<A> sp = wp.lock(); 43 assert(sp.use_count() == 2); 44 assert(sp.get() == sp0.get()); 45 assert(A::count == 1); 46 } 47 assert(A::count == 0); 48 { 49 std::shared_ptr<A> sp0(new A); 50 std::weak_ptr<A> wp(sp0); 51 sp0.reset(); 52 std::shared_ptr<A> sp = wp.lock(); 53 assert(sp.use_count() == 0); 54 assert(sp.get() == 0); 55 assert(A::count == 0); 56 } 57 assert(A::count == 0); 58 } 59
