multithreading - id of "main" thread in c++

Question

Is there a way in c++ to get the id of the "main" program thread?

I see that std::this_thread::get_id() gets the id of the currently executing thread but I need the id of the main, original program thread. I don't see any function to get this.

The reason is that I have some non thread safe internal functions that must only be called on the original thread of the application so to be safe I want to do :-

assert(std::this_thread::get_id() == std::main_thread::get_id());

But there of course isn't a function to do that, and I can't see any way to get that information.

Answer 1

You could save it while this_thread is still the original thread:

std::thread::id main_thread_id;

int main() {
    main_thread_id = std::this_thread::get_id(); // gotcha!
    /* go on */
}