Execute code after death of all child processes

[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 env_sources[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

[Mike Meyer]

Re: Execute code after death of all child processes

mf1987@arcor.de (Markus Franz) writes:
[color=blue]
> 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 env_sources[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.[/color]

import sys, os, time
texts = ['this is text1', 'this is text2']
for current_text in env_sources[0:]:
pid = os.fork()
if pid == 0:
time.sleep(2)
print current_text
break
if pid != 0:
os.waitpid(-1, 0)
print 'this is the end'

Basically, make sure that none of the children run the waitpid and
last print.

<mike
--
Mike Meyer <mwm@mired.or g> http://www.mired.org/home/mwm/
Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information.

[Terry Reedy]

Re: Execute code after death of all child processes


"Markus Franz" <mf1987@arcor.d e> wrote in message
news:576fb15a.0 412240314.13b6c a6f@posting.goo gle.com...

I am a little puzzled about your variable declaration and use:
[color=blue]
> import sys, os, time
> texts = ['this is text1', 'this is text 2'][/color]

You don't seem to use 'texts',
[color=blue]
> for current_text in env_sources[0:]:[/color]

or define 'env_sources',
[color=blue]
> pid = os.fork()
> if pid == 0:
> time.sleep(2)
> print current_text
> break[/color]

so I don't see how this could run (even with indents inserted back). What
am I missing?

Terry J. Reedy