std::unique_ptr::swap

From cppreference.com
< cpplrm; | memorylrm; | unique ptr
Dynamic memory management
Uninitialized storage
(C++17)
Garbage collection support
Miscellaneous
(C++20)
(C++11)
(C++11)
C Library
Low level memory management
void swap(unique_ptr& other) noexcept;
(since C++11)

Swaps the managed objects and associated deleters of *this and another unique_ptr object other.

Parameters

other - another unique_ptr object to swap the managed object and the deleter with

Return value

(none)

Example

#include <iostream>
#include <memory>

struct Foo {
    Foo(int _val) : val(_val) { std::cout << "Foo...\n"; }
    ~Foo() { std::cout << "~Foo...\n"; }
    int val;
};

int main()
{
    std::unique_ptr<Foo> up1(new Foo(1));
    std::unique_ptr<Foo> up2(new Foo(2));

    up1.swap(up2);

    std::cout << "up1->val:" << up1->val << std::endl;
    std::cout << "up2->val:" << up2->val << std::endl;
}

Output:

Foo...
Foo...
up1->val:2
up2->val:1
~Foo...
~Foo...