c++ - std::this_thread::get_id 是否独立于线程的创建方式工作？

Question

std::this_thread::get_id 是否独立于调用它的线程的创建方式(无论是通过 std::thread 还是 OpenMP 或 pthreads 或操作系统 API)？

Answer 1

是的。

无论线程是否由 std::thread 或其他抽象表示，线程都有 ID。

不是作为证明，而是作为说明，您可以从 cppreference 的 std::this_thread::get_id 示例中删除任何 std::thread :

#include <iostream>
#include <thread>
#include <chrono>
#include <mutex>
 
std::mutex g_display_mutex;
 
void foo()
{
    std::thread::id this_id = std::this_thread::get_id();
 
    g_display_mutex.lock();
    std::cout << "thread " << this_id << " sleeping...\n";
    g_display_mutex.unlock();
 
    std::this_thread::sleep_for(std::chrono::seconds(1));
}
 
int main()
{
    foo();
}

到see它打印主线程的 ID。

标准说32.4.4#1 :

Returns: An object of type thread​::​id that uniquely identifies thecurrent thread of execution. No other thread of execution has this idand this thread of execution always has this id. The object returneddoes not compare equal to a default constructed thread​::​id.