threads-in-a-daemon-process.py

#!/usr/bin/env python
"""Show that a daemonic child process may have multiple threads."""
import multiprocessing
import threading

def child_process():
    # start a thread
    threading.Thread(target=child_thread).start()

    # show that we can't have grandchildren processes
    try:
        multiprocessing.Process().start()
    except AssertionError:
        pass
    else:
        assert 0

def child_thread():
    print("a thread in a daemonic child process")

if __name__=="__main__":
    # start daemonic child process
    p = multiprocessing.Process(target=child_process)
    p.daemon = True
    p.start()
    #
    p.join()