How do you make a worker process block while waiting for Value or Array from multiprocessing?

Question

This document shows an example to share state between processes using Value and Array from multiprocessing library:

from multi

Answer 1

To communicate in a thread-safe manner you can use Queue. The get() method blocks if the queue is empty, and waits until a new element is put():

from multiprocessing import Process, Queue

def f(q):
    while True:
        element = q.get()
        print(element)

if __name__ == '__main__':
    q = Queue()
    p = Process(target=f, args=(q,))
    p.start()
    q.put([42, None, 'hello'])
    p.join()