Why does bufsize=1 not work in subprocess.Popen ?
I read in the docs that "bufsize=1" causes line buffering. (for
subprocess.Popen)
The following tiny program launches an executable file and then receives
its output. That works, but I want to
receive each line as it is ouput, not all of the lines at termination,
which is what is happening.
---
from subprocess import Popen, PIPE
from os import remove, sep
p = Popen("." + sep + "myprogram", stdout=PIPE, bufsize=1)
while(1):
line = p.stdout.readline() # get next line
print line,
if line.count("terminator"):
break
--
How can I get line buffering?
Mitchell Timin
--
I'm proud of http://ANNEvolve.sourceforge.net. If you want to write software,
or articles, or do testing or research for ANNEvolve, let me know.
Humans may know that my email address is: (but remove the 3 digit number)
zenguy at shaw666 dot ca
--
http://mail.python.org/mailman/listinfo/python-list
Re: Why does bufsize=1 not work in subprocess.Popen ?
In <[EMAIL PROTECTED]>, I. Myself wrote: > I read in the docs that "bufsize=1" causes line buffering. (for > subprocess.Popen) > > The following tiny program launches an executable file and then receives > its output. That works, but I want to > receive each line as it is ouput, not all of the lines at termination, > which is what is happening. >From the Python side you can only control Python's input buffer but not the output buffer of the external program you are starting. I guess that programs buffers its output. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
Re: Why does bufsize=1 not work in subprocess.Popen ?
Marc 'BlackJack' Rintsch wrote: > In <[EMAIL PROTECTED]>, I. Myself wrote: > > >> I read in the docs that "bufsize=1" causes line buffering. (for >> subprocess.Popen) >> >> The following tiny program launches an executable file and then receives >> its output. That works, but I want to >> receive each line as it is ouput, not all of the lines at termination, >> which is what is happening. >> > > From the Python side you can only control Python's input buffer but not > the output buffer of the external program you are starting. I guess that > programs buffers its output. > > Ciao, > Marc 'BlackJack' Rintsch > That makes sense. I remember now that someone told me that Windows sends line-by-line only to the screen. To a pipe it sends buffers full. Thanks, Mitchell Timin -- I'm proud of http://ANNEvolve.sourceforge.net. If you want to write software, or articles, or do testing or research for ANNEvolve, let me know. Humans may know that my email address is: (but remove the 3 digit number) zenguy at shaw666 dot ca -- http://mail.python.org/mailman/listinfo/python-list
