os.fork() question?

[Ishwar Rattan]

Info at http://doc.python.org/ on os.fork() says that
it has 'unix' semantics (on a UNIX box) on return values
child pid in parent, 0 in child, no mention of failure?

So, what does it return on failure? I tried it under Linux
with Python-2.3.4, after few thousand forks the system just hangs!
(does not return/report fork failure)

Another question on module 'mutex' (stumbuled on it while looking
for info on threads). What is its purpose? (sample code for usage
of lock() and unlock() will be nice too).

-ishwar

 

[Erik Heneryd]

Info at http://doc.python.org/ on os.fork() says that
it has 'unix' semantics (on a UNIX box) on return values
child pid in parent, 0 in child, no mention of failure?

So, what does it return on failure? I tried it under Linux
with Python-2.3.4, after few thousand forks the system just hangs!
(does not return/report fork failure)

It raises OSError.


Erik

 

[Ishwar Rattan]

It raises OSError.


Erik

The following code when executed kills controlling xterm+X-window system,
but the system does not hang.

-ishwar
---
import os, signal, sys, time

def child():
signal.pause()
print 'this from child with pid: ', os.getpid()
sys.exit(2)

def main():
print 'forking child..'
while 1:
try:
cpid = os.fork()
except OSError:
raise 'fork failed..'
if cpid == 0:
child()
else:
print 'fork success..', cpid

main()
-----