New submission from Alex Robinson:
A pyinstaller 3.0 frozen .exe Python 2.7.10 program under Windows 7 that uses a
multiprocessing.Queue to send things to a multiprocessing.Process leads to the
process getting access-is-denied exceptions on every q.get() call.
And, when the program can't exit. Or leaves a dangling process for every
Process.
An unsatisfying fix for this is to put the following code somewhere in the
program:
"""
Do what must be done to make multiprocessing work in .exe files.
This involves monkey patching multiprocessing.forking under Windows
so when the a program using a multiprocessing.Process exits,
there won't be processes left running.
Hint from
http://stackoverflow.com/questions/33764448/pathos-multiprocessing-pipe-and-queue-on-windows
. The bottom line is we get "access is denied" when trying
. to get from the multiprocessing.Queue when we're an .exe file.
. So, in multiprocessing.forking.duplicate(),
. we change 'inheritable' to default to True
. from the normal code's False.
"""
import sys
import multiprocessing
import multiprocessing.forking
#
#
#
#
def duplicate(handle, target_process = None, inheritable = True) :
return(multiprocessing.forking.kludge_to_fix_dangling_processes(handle,
target_process, inheritable))
if (not hasattr(multiprocessing.forking, 'kludge_to_fix_dangling_processes'))
and (sys.platform == 'win32') :
multiprocessing.forking.kludge_to_fix_dangling_processes =
multiprocessing.forking.duplicate
multiprocessing.forking.duplicate = duplicate
----------
components: Library (Lib)
messages: 258895
nosy: alex_python_org
priority: normal
severity: normal
status: open
title: Windows frozen .exe multiprocessing.Queue access is denied exception
type: behavior
versions: Python 2.7
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Python tracker <[email protected]>
<http://bugs.python.org/issue26195>
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