Thread-ID is always the same in my boost::asio::thread_pool

I tried the example from the boost docs:

#include <boost/thread/thread.hpp>
#include <iostream>
#include <boost/asio/post.hpp>
#include <boost/asio/thread_pool.hpp>

int count = 0;

void my_task() {
    count++;
    const auto my_count = count;
    std::cout << "Task " << my_count << ") BEGIN: Thread-ID:" << boost::this_thread::get_id << std::endl;
    boost::this_thread::sleep(1000000000);
    std::cout << "Task " << my_count << ") END:   Thread-ID:" << boost::this_thread::get_id << std::endl;
    
}

int main(int argc, char** argv) {

    std::cout << "Main-thread-ID:  " << boost::this_thread::get_id << std::endl;
    
    // Launch the pool with two threads.
    boost::asio::thread_pool pool(2);

    // Submit a function to the pool.
    boost::asio::post(pool, my_task);
    boost::asio::post(pool, my_task);
    boost::asio::post(pool, my_task);
    boost::asio::post(pool, my_task);
    boost::asio::post(pool, my_task);

    // Wait for all tasks in the pool to complete.
    pool.join();

    return 0;
}

The output is:

Main-thread-ID:  00CC96C6
Task 1) BEGIN: Thread-ID:00CC96C6
Task 2) BEGIN: Thread-ID:00CC96C6
Task 1) END:   Thread-ID:00CC96C6
Task 3) BEGIN: Thread-ID:00CC96C6
Task 2) END:   Thread-ID:00CC96C6
Task 4) BEGIN: Thread-ID:00CC96C6
Task 4) END:   Thread-ID:00CC96C6
Task 3) END:   Thread-ID:00CC96C6
Task 5) BEGIN: Thread-ID:00CC96C6
Task 5) END:   Thread-ID:00CC96C6

Why does the same thread ID show up the whole time? Have I done something wrong? It still does execute my tasks parallel. So, I'm not too worried.

I've seen the same behavior when I tried a similiar example with boost::thread_group.

Thanks Kaldrr! I changed all occurances of boost::this_thread::get_id to boost::this_thread::get_id() which led to the expected output of different Thread IDs:

Main-thread-ID:  5a78
Task 1) BEGIN: Thread-ID:77d0
Task 1) BEGIN: Thread-ID:5f34
Task 1) END:   Thread-ID:5f34
Task 1) END:   Thread-ID:77d0
Task 2) BEGIN: Thread-ID:5f34
Task 3) BEGIN: Thread-ID:77d0
Task Task 2) END:   Thread-ID:5f34
3) END:   Thread-ID:77d0
Task 4) BEGIN: Thread-ID:77d0
Task 4) END:   Thread-ID:77d0