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

Chris Withers chris at python.org
Wed Dec 5 17:40:40 CET 2012


On 05/12/2012 16:34, Antoine Pitrou wrote:

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.

Because lazy/busy people don't bother reading the links underneath docs...

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().

I agree, however, I also:

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

One of them quoted the docs at me at proof that his code must be correct ;-)

Chris

-- Simplistix - Content Management, Batch Processing & Python Consulting - http://www.simplistix.co.uk



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