std::weak_ptr<T>::reset

 

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std::weak_ptr

成員函式

weak_ptr::weak_ptr

weak_ptr::~weak_ptr

weak_ptr::operator=

修改器

weak_ptr::reset

weak_ptr::swap

觀察器

weak_ptr::use_count

weak_ptr::expired

weak_ptr::lock

weak_ptr::owner_before

weak_ptr::owner_hash (C++26)

weak_ptr::owner_equal (C++26)

非成員函式

swap(std::weak_ptr)

輔助類

atomic<std::weak_ptr> (C++20)

推導指南(C++17)

 

void reset() noexcept;		(C++11 起)

釋放對所管理物件的引用。呼叫後，*this 不管理任何物件。

引數

(無)

返回值

(無)

示例

執行此程式碼

#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';
}

輸出

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

參閱

expired

檢查引用的物件是否已被刪除 (public member function)