Blocking ctrl-c to os.popen() or os.system()

[Sandeep Gupta]

Thanks, Chad.  I was not clear in my previous message.

I am running on Linux, but the script I'm writing will also be using on
Win2k.

What I meant was I start the command and programatically wait for it to
finish.  I wait for the command to finish by doing an f.read() on the stdout
returned from popen*().  While I am waiting for it to finish, if the user
types ctrl-c, the command receives the interrupt.

I also posted the question to the unix.shell newsgroup.  Apparently, the
command subprocess is allowed to turn on the signal again, and that may be
happening in my case.  If I turn off signal handling for SIGINT, and then
run the command "ls -R / | wc -l" (which takes a minute to run on my
system), then I am not able to interrupt the command.  But if my command is
"cvs diff", cvs receives the ctrl-c.

Any other suggestions?
Thanks

"Chad Netzer" <cnetzer at mail.arc.nasa.gov> wrote in message
news:mailman.1041737589.4382.python-list at python.org...
> On Saturday 04 January 2003 14:00, Sandeep Gupta wrote:
> > I am executing a command from python via os.popen().  While the
> > command is executing, if I type ctrl-c, the command receives the
> > interrupt.
>
> What is your system?  On Linux, with a trivial (and perhaps foolish)
example
> it seems that the Python interpreter does indeed get the ctrl-c:
>
> ~~~~~~~~~~~~~~~~~~~~~~~~
> import os
> import time
>
> if __name__ == '__main__':
>     cmd_str = "sleep 20"
>     print 'Running "%s"' % cmd_str
>     os.popen2( cmd_str )
>
>     print "Python now sleeping for 20 seconds."
>     try:
>         time.sleep(20)
>     except KeyboardInterrupt:
>         print "ctrl-c was pressed"
> ~~~~~~~~~~~~~~~~~~~~~~~~
>
> $ python popen_test.py
> Running "sleep 20"
> Python now sleeping for 20 seconds.
> ctrl-c was pressed
>
>
> Note - I pressed ctrl-c to get that result. :)
>
> --
> Bay Area Python Interest Group - http://www.baypiggies.net/
>
> Chad Netzer
> cnetzer at mail.arc.nasa.gov
>