I have a very simple script which is the following:
import multiprocessing as multi def call_other_thing_with_multi(): P = multi.Pool(3) P.map(other_thing, range(0,5)) P.join() def other_thing(arg): print(arg) return arg**2. call_other_thing_with_multi() When I call this, my code hangs at perpetuity. This is on windows with python 2.7.
Thanks for any guidance!
As per documentation, you need to call close() before join():
import multiprocessing as multi def call_other_thing_with_multi(): P = multi.Pool(3) P.map(other_thing, range(0,5)) P.close() # <-- calling close before P.join() P.join() print('END') def other_thing(arg): print(arg) return arg**2. call_other_thing_with_multi() Prints:
0 1 2 3 4 END EDIT: Better is use context manager, to not forget to call close():
def call_other_thing_with_multi(): with multi.Pool(3) as P: P.map(other_thing, range(0,5)) print('END') 
