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std::enable_shared_from_this::operator=(3) C++ Standard Libary std::enable_shared_from_this::operator=(3)

NAME

std::enable_shared_from_this::operator= - std::enable_shared_from_this::operator=

Synopsis


enable_shared_from_this<T>& operator=( const (since C++11)
enable_shared_from_this<T> &obj ) noexcept;


Does nothing; returns *this.

Parameters


obj - an enable_shared_from_this to assign to *this

Return value


*this

Notes


The private std::weak_ptr<T> member is not affected by this assignment operator.

Example


Note: enable_shared_from_this::operator= is defined as protected in order to prevent
accidental slicing but allow derived classes to have default assignment operators.

// Run this code


#include <memory>
#include <iostream>


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() << std::endl;
}

Output:


4

See also


shared_ptr smart pointer with shared object ownership semantics
(C++11) (class template)

2022.07.31 http://cppreference.com