C++:std :: thread的简单返回值？

#include<iostream>
#include<thread>

void print_thread_id() {
    std::thread::id thread_id = std::this_thread::get_id();
    std::cout << "Thread ID: "<< thread_id<< std::endl;
}

int main() {
    std::thread t1(print_thread_id);
    std::thread t2(print_thread_id);

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

    return 0;
}