Python thread and process join() understanding

import threading
import time


def run():
    time.sleep(2)
    print('Current thread name:', threading.current_thread().name)
    time.sleep(2)


if __name__ == '__main__':
    start_time = time.time()
         print('Main thread:', threading.current_thread().name)

    thread_list = []

    for i in range(5):
        t = threading.Thread(target=run)
        thread_list.append(t)

    for t in thread_list:
        # t.setDaemon(True)
        t.start()
        # t.join()


         print('End of main thread')
         print('Use time:', time.time()-start_time)

The execution of the main thread is completed, the sub-thread will continue to execute and the program will end

When t.setDaemon(True) starts the daemon process, the main thread execution is completed, and the child thread has not yet completed, the program will exit directly

Obviously, setDaemon is False by default

When using t.join(), the main thread has been waiting for the completion of the child thread before it ends and the program exits

The role of join is reflected, the main thread task is completed, enters the blocking state, and waits for other child threads to complete before terminating, which has the effect of thread synchronization!

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