[Python-Dev] slightly misleading Popen.poll() docs (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Wed Dec 5 17:34:29 CET 2012

Le Wed, 05 Dec 2012 16:08:46 +0000, Chris Withers <chris at simplistix.co.uk> a écrit :

Hi All,

Would anyone object to me making a change to the docs for 2.6, 2.7 and 3.x to clarify the following: http://docs.python.org/3/library/subprocess.html#subprocess.Popen.poll

The doc looks clear to me. poll() returns the returncode attribute which is described thusly:

"A None value indicates that the process hasn’t terminated yet."

Therefore, I don't understand the confusion. poll() is explicitly non-blocking, and it is silly to expect it to return a process return code when the process hasn't returned yet (!). The correct answer is to use the wait() method (or communicate()), which is described two lines below poll().

May I suggest your colleagues didn't read the doc at all?

Regards

Antoine.

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