Unbuffer stdout?

Greg Ewing (using news.cis.dfn.de) me at privacy.net
Wed Mar 26 06:48:59 CET 2003


Francis Avila wrote:
>>>>sys.stdout.write( os.popen("yes", 'r', 0).read() )
> 
> 
> hangs forever (with some disk activity after a while) until you interrupt
> the interpreter.  I strongly suspect this is because the output is getting
> trapped in a buffer until the command exits

No, what's happening is that the .read() is trying to
read *all* the output generated by the command... but
the "yes" command generates an infinite amount of
output! So the read() never returns.

There will be some buffering, but probably only a
few K worth. Try doing .readline() in a loop and
printing out each thing that it returns. You
should get some output very quickly.

-- 
Greg Ewing, Computer Science Dept,
University of Canterbury,	
Christchurch, New Zealand
http://www.cosc.canterbury.ac.nz/~greg





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