Getting the pid of the process launched by my perl program

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Hi PERL Monks,

I'd like to get the process id of the background process launched from within my perl program. I'm trying to do this in my perl code -

system (./a.out &);
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I want know the process id of the newly lauched process "a.out". I can get this in a C shell script -

./a.out &
echo $! > /tmp/pidfile
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How will I do this in perl ? Also, I don't want to call the C shell script from the perl program.

What do I do ??

thanks in advance !!

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Re: Getting the pid of the process launched by my perl program by edan (Curate) on Dec 21, 2004 at 12:40 UTC
`$SIG{CHLD} = 'IGNORE'; # on systems where it's supported defined( my $pid = fork ) or die "fork: $!"; if ( $pid ) { # parent print "child pid is $pid\n"; } else { # child exec("a.out") or die "exec: $!"; }` [download] -- edan	[reply] [d/l]
Re^2: Getting the pid of the process launched by my perl program by Anonymous Monk on Dec 22, 2004 at 11:05 UTC
Thanx much edan and ozone !!	[reply]
Re^2: Getting the pid of the process launched by my perl program by Anonymous Monk on Apr 12, 2010 at 11:20 UTC
I'm using the same logic to monitor the child process with a timer in the parent. On maximum timeout I'm killing the child process. The issue is I'm running an exe from the child which doesn't die on kill the child. I tried to explicitly kill the process with taskkill on windows and it works fine. But I face portability issues because of using taskkill. Can anybody help on this?	[reply]
Re: Getting the pid of the process launched by my perl program by ozone (Friar) on Dec 21, 2004 at 12:37 UTC
The current process id is stored in $$, but I suspect that what you're trying to do is find out when the background process has died, right? If so, you'd be better off using fork(), exec() and waitpid. A quick search produced a helpfull node that could help: ForkMe	[reply]