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 19struct A 20{ 21 static int count; 22 23 A() {++count;} 24 A(const A&) {++count;} 25 ~A() {--count;} 26}; 27 28int A::count = 0; 29 30int 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