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Date: Wed, 18 May 2011 13:35:51 -0400
From: Ryan Johnson <ryanjohn AT ece DOT cmu DOT edu>
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To: "C. Woody Butler" <charles DOT butlerjr AT constellation DOT com>
CC: cygwin AT cygwin DOT com
Subject: Re: trying to get the process id for a spawned process to wait for it
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On 2:59 PM, C. Woody Butler wrote:
> Hi - I'm trying to launch a set number of threads,
> wait for them to finish, launch another set of
> threads, wait and repeat until there's no more input.
>
> so - I've got this (this is in the middle
> of a loop reading a file):
>
> Jobs=$Jobs + 1
What shell are you using? In bash, at least, the above won't work -- you 
want Jobs=((Jobs+1))

> /tibcoresources/appmanage.exe<<lots of params>>  &
> PID=$!
> echo $PID is the process
>
> if [[ $Jobs -gt 2 ]]
> then
> {
> 	echo pausing
> 	wait $PID
> 	Jobs=0
> 	echo starting
> }
> fi
>
> But - I don't get anything back from $!
> so the wait doesn't wait and I end up
> launching a bunch of processes and taking
> down the server, etc, etc, etc.
Just to be sure, you've confirmed that the problem arises because the 
if-then body runs with an empty $PID? Do the two echo commands fire?

Ryan



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