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std::weak_ptr<T>::reset - cppreference.com

来自cppreference.com

(C++11 起)
(C++26 起为 constexpr)

释放被管理对象的所有权。调用后 *this 不再管理对象。

示例

#include <iostream>
#include <memory>

int main()
{
    auto shared = std::make_shared<int>(), shared2 = shared, shared3 = shared2;
    
    auto weak = std::weak_ptr<int>{shared};
    
    std::cout << std::boolalpha 
              << "shared.use_count()：" << shared.use_count() << '\n'
              << "weak.use_count()：" << weak.use_count() << '\n'
              << "weak.expired()：" << weak.expired() << '\n';
    
    weak.reset();
    
    std::cout << "weak.reset();\n"
              << "shared.use_count()：" << shared.use_count() << '\n'
              << "weak.use_count()：" << weak.use_count() << '\n'
              << "weak.expired()：" << weak.expired() << '\n';
}

输出： 

shared.use_count()：3
weak.use_count()：3
weak.expired()：false
weak.reset();
shared.use_count()：3
weak.use_count()：0
weak.expired()：true

参阅