Python 2.7 on Windows, “assert main_name not in sys.modules, main_name” for all multiprocessing examples

问题:

There is following simple code:

from multiprocessing import Process, freeze_support  def foo():     print 'hello'  if __name__ == '__main__':     freeze_support()     p = Process(target=foo)     p.start() 

It works good on Linux or Windows with Python 3.3, but fails on Windows with Python 2.7.

Traceback (most recent call last):   File "", line 1, in    File "c:\Python27\lib\multiprocessing\forking.py", line 346, in main     prepare(preparation_data)   File "c:\Python27\lib\multiprocessing\forking.py", line 454, in prepare     assert main_name not in sys.modules, main_name AssertionError: thread 

Generally speaking, all multiprocessing examples i tried fail on that setup. Why?

回答1:

This is a known bug:

http://bugs.python.org/issue10845

Not sure if this will ever get ported to 2.7.X.

文章来源: Python 2.7 on Windows, “assert main_name not in sys.modules, main_name” for all multiprocessing examples