62 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9// <memory>10 11// weak_ptr12 13// shared_ptr<T> lock() const;14 15#include <memory>16#include <cassert>17 18#include "test_macros.h"19 20struct A21{22 static int count;23 24 A() {++count;}25 A(const A&) {++count;}26 ~A() {--count;}27};28 29int A::count = 0;30 31int main(int, char**)32{33 {34 std::weak_ptr<A> wp;35 std::shared_ptr<A> sp = wp.lock();36 assert(sp.use_count() == 0);37 assert(sp.get() == 0);38 assert(A::count == 0);39 }40 {41 std::shared_ptr<A> sp0(new A);42 std::weak_ptr<A> wp(sp0);43 std::shared_ptr<A> sp = wp.lock();44 assert(sp.use_count() == 2);45 assert(sp.get() == sp0.get());46 assert(A::count == 1);47 }48 assert(A::count == 0);49 {50 std::shared_ptr<A> sp0(new A);51 std::weak_ptr<A> wp(sp0);52 sp0.reset();53 std::shared_ptr<A> sp = wp.lock();54 assert(sp.use_count() == 0);55 assert(sp.get() == 0);56 assert(A::count == 0);57 }58 assert(A::count == 0);59 60 return 0;61}62