homepage

this occurs for me running on Mac OSX Leopard. The equivalent code
using "processing" in python 2.5 works fine, which is how I found this
bug - my code hung when upgraded to 2.6. Basically initiating a
multiprocessing.Pool inside of multiprocessing.Process hangs the
application. Below is code which illustrates the issue on both py2.6
and py3.0:
 from multiprocessing import Pool, Process
 import sys
 def f(x):
 return x*x
 def go():
 pool = Pool(processes=4) 
 x = pool.map(f, [1, 2, 3, 4, 5, 6, 7])
 sys.stdout.write("result: %s\n" % x)
 def go2():
 x = map(f, [1,2,3,4,5,6,7])
 sys.stdout.write("result: %s\n" % x)
 # pool alone, fine
 go()
 # process alone, fine
 p = Process(target=go2)
 p.start()
 p.join()
 # use both, hangs
 p = Process(target=go)
 p.start()
 p.join()