swap(std::jthread)(3)

💖 NAME 💖

okay so bestie, this is the swap(std::jthread) page from the C++ Standard Libary manual ✨ and the name section is literally swap(std::jthread) — swap(std::jthread) 💅

🦋 Synopsis 🦋

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

okay so what it do: it overloads the std::swap algorithm for std::jthread 🔁. It exchanges the state of lhs with that of rhs. It effectively calls lhs.swap(rhs). That's the whole vibe.

Now the important little caveat, bestie: this function is not visible to ordinary unqualified or qualified lookup 🚫👀. It can only be found by argument-dependent lookup when std::jthread is an associated class of the arguments. iykyk.

🎀 Parameters 🎀

• lhs, rhs — the jthreads whose states we're swapping 💅

🫶 Return value 🫶

(none) — literally no return value, bestie. Nothing comes back. Periodt. ✨

🌈 Example 🌈

Run this code, bestie — it's the whole example, no edits:

// Run this code

#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()
{
    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 ⭐

Here's the possible output, bestie:

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) ✨

and that's the whole swap(std::jthread)(3) page, sourced from http://cppreference.com, version/date 2024.06.10 — bye bestie, go swap those jthreads 💅💖