std::thread::swap - cppreference.com

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

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

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

int main()
{
    std::thread t1(foo);
    std::thread t2(bar);

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

    std::swap(t1, t2);

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

    t1.swap(t2);

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

    t1.join();
    t2.join();
}

线程 1 id: 140185268262656
线程 2 id: 140185259869952
std::swap(t1, t2) 后:
线程 1 id: 140185259869952
线程 2 id: 140185268262656
t1.swap(t2) 后:
线程 1 id: 140185268262656
线程 2 id: 140185259869952