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: - don't see any harm in the change I propose - do see a slight improvement for the comprehending impaired ;-)

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

On Thu, 06 Dec 2012 04:15:08 +1100 Steven D'Aprano wrote:

On 06/12/12 03:08, Chris Withers wrote:

...

I'd like to change the docs for poll() to say:

""" Check if child process has terminated. If it has, the returncode attribute will be set and that value will be returned. If it has not, None will be returned and the returncode attribute will remain None. """

Any objections?

Possibly because it is 4am here, I had to read this three times to understand it. How is this instead?

""" Check if child process has terminated. Returns None while the child is still running, any non-None value means that the child has terminated. In either case, the return value is also available from the instance's returncode attribute. """

I like this wording. Regards Antoine.

On 05/12/2012 17:15, Steven D'Aprano wrote:

""" Check if child process has terminated. Returns None while the child is still running, any non-None value means that the child has terminated. In either case, the return value is also available from the instance's returncode attribute. """

Do you want to make the commit or shall I? Chris -- Simplistix - Content Management, Batch Processing & Python Consulting - http://www.simplistix.co.uk