popen3 with python

[Maric]

That's it i think.
here my piece of code to prevent it and scan every char on either stdin or
stdout

raccroche = select.poll()
stdout_upd = select.poll()
stderr_upd = select.poll()

# Lancement de la commande
pipe_out  = os.popen3(tempCmd)
stdin, stdout, stderr = pipe_out
for i in pipe_out :
	raccroche.register(i.fileno(), select.POLLHUP)
stdout_upd.register(stdout, select.POLLIN)
stderr_upd.register(stderr, select.POLLIN)
s, e = (None,)*2
s_looping, e_looping = (0,)*2

# tant que le processus fils n'a pas raccroché ou qu'il ne s'est pas endormi
!
while(s_looping or e_looping or not raccroche.poll(0)):

	events.clear()

	while(s!='' and stdout_upd.poll(0)) :
     		s = os.read(stdout.fileno(),1)
      	if s == '' : break
      	# do something with s

	while(e!='' and stderr_upd.poll(0)) :
      	e = os.read(stderr.fileno(),1)
            if e == '' : break
            # do something with e

	# on empêche au processus fils de s'endormir
	if s_looping :
      	self.exitStatus = stdout.close()
            break
      if s == '' : s_looping = 1
      if e_looping :
           stderr.close()
           break
	if e == '' : e_looping = 1


# Récupération des informations utiles
if not stdout.closed : self.exitStatus = stdout.close()
if not stderr.closed : stderr.close()
if self.exitStatus is None : self.exitStatus = 0



----Message d'origine-----
De : Thomas Guettler [mailto:guettli at thomas-guettler.de]
Envoyé : dimanche 10 mars 2002 23:55
À : Maric MICHAUD
Objet : popen3 with python


Hi Maric!

You replied to my question. I found the answer, maybe you have the
same deadlock condition:

If there is a lot of output on e.g. stderr and you start reading
from stdin you have a deadlock

Example:

The subprocess writes a lot of data to stderr and blocks.
In your application you use:

(stdin, stdout, stderr)=popen3("command_with_a_lot_of_output")
stdout.read()

--> deadlock

 thomas
--
Thomas Guettler <guettli at thomas-guettler.de>
http://www.thomas-guettler.de