NAME¶

swap(std::jthread) - swap(std::jthread)

Synopsis¶

friend void swap( jthread &lhs, jthread &rhs ) noexcept; (since C++20)

Overloads the std::swap algorithm for std::jthread. Exchanges the state of lhs with
that of rhs. Effectively calls lhs.swap(rhs). This function is not visible to
ordinary unqualified or qualified lookup, and can only be found by
argument-dependent lookup when std::jthread is an associated class of the arguments.

Parameters¶

lhs, rhs - jthreads whose states to swap

Return value¶

(none)

Example¶

// Run this code

#include <iostream>
#include <thread>
#include <chrono>

void foo()
{
std::this_thread::sleep_for(std::chrono::seconds(1));
}

void bar()
{
std::this_thread::sleep_for(std::chrono::seconds(1));
}

int main()
{
using std::swap;

std::jthread t1(foo);
std::jthread t2(bar);

std::cout << "thread 1 id: " << t1.get_id() << '\n'
<< "thread 2 id: " << t2.get_id() << '\n';

swap(t1, t2);

std::cout << "after std::swap(t1, t2):" << '\n'
<< "thread 1 id: " << t1.get_id() << '\n'
<< "thread 2 id: " << t2.get_id() << '\n';

t1.swap(t2);

std::cout << "after t1.swap(t2):" << '\n'
<< "thread 1 id: " << t1.get_id() << '\n'
<< "thread 2 id: " << t2.get_id() << '\n';

}

Possible output:¶

thread 1 id: 1892
thread 2 id: 2584
after std::swap(t1, t2):
thread 1 id: 2584
thread 2 id: 1892
after t1.swap(t2):
thread 1 id: 1892
thread 2 id: 2584

See also¶

swap swaps two jthread objects
(public member function)