Sorry for being not more specific but I'm not absolutely certain whether
I encountered a bug or did anything wrong:

The (stupid) code below results in a stall forever or not at 'p0.join()'
depending on the value of TROUBLE_MAKER.

Any help, thoughts, comments?

Thank you for your time.

Michael

# ----------------------------------------------------------------------

from multiprocessing import Process, Queue

# bit vector size
BVS=8

#
TROUBLE_MAKER=12  # for greater values p0.join() is never satisfied...

def evaluate(q, id, start=0, stop=2**BVS):

    cmin = {0: []}

    for mask0 in range(start, stop):
        for mask1 in range(0, 2**BVS):
            for mask2 in range(mask1, TROUBLE_MAKER):
                cmin[0].append((mask0, mask1, mask2))

    print 'process %d finished (dict layout: %d/%d)...' % (id,
len(cmin), len(cmin[0]))
    q.put(cmin.copy())
    q.close()


if __name__ == '__main__':

    q0 = Queue()
    q1 = Queue()
    q2 = Queue()
    q3 = Queue()

    part = 2**BVS/4
    p0 = Process(target=evaluate, args=(q0, 0, 0*part, 1*part),
name='worker_0')
    p1 = Process(target=evaluate, args=(q1, 1, 1*part, 2*part),
name='worker_1')
    p2 = Process(target=evaluate, args=(q2, 2, 2*part, 3*part),
name='worker_2')
    p3 = Process(target=evaluate, args=(q3, 3, 3*part, 4*part),
name='worker_3')
    p0.start()
    print 'process 0 started...'
    p1.start()
    print 'process 1 started...'
    p2.start()
    print 'process 2 started...'
    p3.start()
    print 'process 3 started...'
    # main process stalls at p0.join() for bigger TROUBLE_MAKER
    p0.join()
    p1.join()
    p2.join()
    p3.join()
    res0 = q0.get()
    res1 = q1.get()
    res2 = q2.get()
    res3 = q3.get()
    print 'results fetched...'

# ----------------------------------------------------------------------

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