std::thread::get_id(3)

🌸 std::thread::get_id(3) 🌸

okay so bestie, welcome to the <pink>std::thread::get_id</pink> page — it's filed under the C++ Standard Libary manual (that's literally how the header spells it, not me, iykyk 💅) and it's short, sweet, and honestly kinda iconic.

---

✨ NAME ✨

std::thread::get_id — literally std::thread::get_id. that's the whole name. no notes. 🎀

---

🦋 Synopsis 🦋

std::thread::id get_id() const noexcept;

(since C++11)

what it does: returns a value of std::thread::id identifying the thread associated with *this. that's it. that's the vibe check. ✨

---

🍓 Parameters 🍓

(none) — nothing to pass in, bestie. it takes zero arguments, it's low maintenance, we love that for it. 🫶

---

💖 Return value 💖

a value of type std::thread::id identifying the thread associated with *this.

and here's the important part 👑: if there is no thread associated, then a default constructed std::thread::id is returned. so like... the id of nobody. a ghost id. 😭💀

---

🌈 Example 🌈

run this code, bestie:

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

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

int main()
{
    std::thread t1(foo);
    std::thread::id t1_id = t1.get_id();

    std::thread t2(foo);
    std::thread::id t2_id = t2.get_id();

    std::cout << "t1's id: " << t1_id << '\n';
    std::cout << "t2's id: " << t2_id << '\n';

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

    std::cout << "t1's id after join: " << t1.get_id() << '\n';
    std::cout << "t2's id after join: " << t2.get_id() << '\n';
}

⭐ Possible output ⭐

t1's id: 140146221688576
t2's id: 140146213295872
t1's id after join: thread::id of a non-executing thread
t2's id after join: thread::id of a non-executing thread

see how the ids change after join()? that's the ghost-id situation from the Return value section showing up to the party 🧚 — once the threads are joined, get_id() hands you back a non-executing thread id. slay. 💅

---

🔥 See also 🔥

• id — represents the id of a thread (public member class) 🎀
• joinable — checks whether the thread is joinable, i.e. potentially running in parallel (public member function) 🦋

---

and that's the whole page! periodt ✨ source + version + date for the record: http://cppreference.com, 2024.06.10, std::thread::get_id(3) — mwah, catch you in the next manpage bestie 💜🌸👑