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multiprocessing package incompatible with PyObjC #57767
Description
| BPO | 13558 |
|---|---|
| Nosy | @ronaldoussoren, @ned-deily |
| Superseder | |
| Files |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = 'https://github.com/ronaldoussoren'
closed_at = <Date 2012-01-04.03:34:27.530>
created_at = <Date 2011-12-08.20:26:13.579>
labels = ['OS-mac', 'type-bug']
title = 'multiprocessing package incompatible with PyObjC'
updated_at = <Date 2012-01-04.03:34:27.528>
user = 'https://bugs.python.org/mrmekon'bugs.python.org fields:
activity = <Date 2012-01-04.03:34:27.528>
actor = 'ned.deily'
assignee = 'ronaldoussoren'
closed = True
closed_date = <Date 2012-01-04.03:34:27.530>
closer = 'ned.deily'
components = ['macOS']
creation = <Date 2011-12-08.20:26:13.579>
creator = 'mrmekon'
dependencies = []
files = ['23884']
hgrepos = []
issue_num = 13558
keywords = []
message_count = 3.0
messages = ['149051', '149053', '150580']
nosy_count = 3.0
nosy_names = ['ronaldoussoren', 'ned.deily', 'mrmekon']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '8713'
type = 'behavior'
url = 'https://bugs.python.org/issue13558'
versions = ['Python 2.7', 'Python 3.2', 'Python 3.3']
Activity
mrmekon commentedon Dec 8, 2011
The multiprocessing package appears to spawn a new process by calling only fork(). Apple's CoreFoundation libraries (and possibly more, I do not know the full extent) *require* new processes to be spawned with the full fork()+exec*() combo.
When using PyObjC to access native Mac libraries, Python's multithreading library is not usable. The error thrown is:
------------------------
The process has forked and you cannot use this CoreFoundation functionality safely. You MUST exec().
Break on __THE_PROCESS_HAS_FORKED_AND_YOU_CANNOT_USE_THIS_COREFOUNDATION_FUNCTIONALITY___YOU_MUST_EXEC__() to debug.
------------------------
Test code: https://gist.github.com/1448398
ned-deily commentedon Dec 8, 2011
(Reference original discussion in pyobjc-dev mailing list archived here: http://comments.gmane.org/gmane.comp.python.pyobjc.devel/5965)
ned-deily commentedon Jan 4, 2012
bpo-8713 proposes adding the option of using processes for multiprocessing rather than bare forks. Let's consolidate this issue with that one.