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copied!<p>The <code>multiprocessing.pool.Pool</code> class creates the worker processes in its <code>__init__</code> method, makes them daemonic and starts them, and it is not possible to re-set their <code>daemon</code> attribute to <code>False</code> before they are started (and afterwards it's not allowed anymore). But you can create your own sub-class of <code>multiprocesing.pool.Pool</code> (<code>multiprocessing.Pool</code> is just a wrapper function) and substitute your own <code>multiprocessing.Process</code> sub-class, which is always non-daemonic, to be used for the worker processes.</p> <p>Here's a full example of how to do this. The important parts are the two classes <code>NoDaemonProcess</code> and <code>MyPool</code> at the top and to call <code>pool.close()</code> and <code>pool.join()</code> on your <code>MyPool</code> instance at the end.</p> <pre><code>#!/usr/bin/env python # -*- coding: UTF-8 -*- import multiprocessing # We must import this explicitly, it is not imported by the top-level # multiprocessing module. import multiprocessing.pool import time from random import randint class NoDaemonProcess(multiprocessing.Process): # make 'daemon' attribute always return False def _get_daemon(self): return False def _set_daemon(self, value): pass daemon = property(_get_daemon, _set_daemon) # We sub-class multiprocessing.pool.Pool instead of multiprocessing.Pool # because the latter is only a wrapper function, not a proper class. class MyPool(multiprocessing.pool.Pool): Process = NoDaemonProcess def sleepawhile(t): print("Sleeping %i seconds..." % t) time.sleep(t) return t def work(num_procs): print("Creating %i (daemon) workers and jobs in child." % num_procs) pool = multiprocessing.Pool(num_procs) result = pool.map(sleepawhile, [randint(1, 5) for x in range(num_procs)]) # The following is not really needed, since the (daemon) workers of the # child's pool are killed when the child is terminated, but it's good # practice to cleanup after ourselves anyway. pool.close() pool.join() return result def test(): print("Creating 5 (non-daemon) workers and jobs in main process.") pool = MyPool(5) result = pool.map(work, [randint(1, 5) for x in range(5)]) pool.close() pool.join() print(result) if __name__ == '__main__': test() </code></pre>

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