Execute code after death of all child processes - (corrected posting)

[Markus Franz]

Hallo!


I have a problem with this little script written in Python:


import sys, os, time
texts = ['this is text1', 'this is text 2']
for current_text in env_sources[0:]:
pid = os.fork()
if pid == 0:
time.sleep(2)
print current_text
break

As you is create some child processes depending on the number of vars
in ?texts?. My problem is: How can I run some code after all child
processes have been finished? (The code should be run only in the
parent process.)

I tried:

import sys, os, time
texts = ['this is text1', 'this is text 2']
for current_text in texts[0:]:
pid = os.fork()
if pid == 0:
time.sleep(2)
print current_text
break
os.waitpid(-1, 0)
print 'this is the end'

But this didn't work, 'this is the end' will be showed several times.

Can you help me?

Tanks.


Markus

[Jeff Epler]

Re: Execute code after death of all child processes - (correctedposti ng)

First, you'll want to exit from each forked copy, or else it will reach
the code-after-the-for-loop:
import sys, os, time
texts = ['this is text1', 'this is text 2']
for current_text in texts[0:]:
pid = os.fork()
if pid == 0:
time.sleep(2)
print current_text
raise SystemExit

Next, you'll want to wait for each process you started:
for current_text in texts:
os.waitpid(-1, 0)
print 'this is the end'


$ python /tmp/franz.py
this is text1
this is text 2
this is the end

Jeff

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