[New-bugs-announce] [issue11459] Python select.select does not correctly report read readyness
report at bugs.python.org
Thu Mar 10 06:04:28 CET 2011
New submission from Novimir Pablant <amicitas at gmail.com>:
I am trying to get the output from an external program into python using `subprocess.Popen` and `select.select`. For some reason though select.select is at times telling me that stdout is not ready to read, even when it is (reading from it works).
This problem exists in python 3.1 & 3.2 but not in python 2.7.
For my particular application I am connecting to external program via ssh. I would not expect that the ssh connection would be an issue.
The program that I am calling produces some output and eventually asks for user input. In the example below I only get a portion of the output, then at some point select.select tells me that read is not available. If I try to read anyway I can keep getting more output. As soon as I press a key (passing something to stdin), select.select tells me that I can read again and I get the rest of the output.
command = ["ssh", "-t", host, "some_program"]
child = subprocess.Popen(command
out = ''
r, w, x = select.select([child.stdout], , , 1.0)
if child.poll() is not None:
out = child.stdout.read(1)
components: Library (Lib)
title: Python select.select does not correctly report read readyness
versions: Python 3.1, Python 3.2
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