std::enable_shared_from_this<T>::operator=

 

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std::enable_shared_from_this

受保护的成员函数

enable_shared_from_this::enable_shared_from_this

enable_shared_from_this::~enable_shared_from_this

enable_shared_from_this::operator=

公有成员函数

enable_shared_from_this::shared_from_this

enable_shared_from_this::weak_from_this (C++17)

 

enable_shared_from_this& operator=( const enable_shared_from_this &rhs ) noexcept;		(自 C++11 起)

不执行任何操作；返回 *this.

参数

rhs

-

另一个要分配给 *this 的 enable_shared_from_this

返回值

*this

注释

仅用于说明的 std::weak_ptr<T> 成员 weak-this 不会受到此赋值运算符的影响。

示例

注意：enable_shared_from_this::operator= 定义为 protected，以防止意外切片，但允许派生类具有默认的赋值运算符。

运行此代码

#include <iostream>
#include <memory>
 
class SharedInt : public std::enable_shared_from_this<SharedInt>
{
public:
    explicit SharedInt(int n) : mNumber(n) {}
    SharedInt(const SharedInt&) = default;
    SharedInt(SharedInt&&) = default;
    ~SharedInt() = default;
 
    // Both assignment operators use enable_shared_from_this::operator=
    SharedInt& operator=(const SharedInt&) = default;
    SharedInt& operator=(SharedInt&&) = default;
 
    int number() const { return mNumber; }
 
private:
    int mNumber;
};
 
int main()
{
    std::shared_ptr<SharedInt> a = std::make_shared<SharedInt>(2);
    std::shared_ptr<SharedInt> b = std::make_shared<SharedInt>(4);
    *a = *b;
 
    std::cout << a->number() << '\n';
}

输出

4

参见

shared_ptr (C++11)

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