perl: how to start child process in background?

[graudeejs]

How to start and get pid of background child process in perl?
in other word how to port these sh lines to perl

#!/bin/sh
exec mplayer -msglevel all=1 -zoom -quiet -idle -input file=$HOME/.playd.fifo >> /dev/null &
echo "$!"


I can't figure it out.....

[SirDice]

Simplest way to do it:

#!/usr/bin/perl

system('mplayer -msglevel all=1 -zoom -quiet -idle -input file=$HOME/.playd.fifo');


A more complicated way to do it would be to use fork().

http://hell.jedicoder.net/?p=82

[graudeejs]

Simplest way to do it:

#!/usr/bin/perl

system('mplayer -msglevel all=1 -zoom -quiet -idle -input file=$HOME/.playd.fifo');


A more complicated way to do it would be to use fork().

http://hell.jedicoder.net/?p=82

No i don't think that will work as i want.

system will return exit code of child process what will not be forked. If i use exec inside single quote it will not work as well.

for will for parent into child and i will have 2 processes of same script (or 1, anyway, as i understand it won't work for me)


All i want to do is fork mplayer, get it's pid and write it down to some file, that i will use later to check if mplayer is running in slave mode.

I want my perl script to fork mplayer, get it's pid, write to file, and continue to work like nothing happen :D


correct me if i'm wrong


here's original code of my sh scipt

MPLAYER_CMD = "mplayer -msglevel all=1 -zoom -quiet -idle -input file=$HOME/.playd.fifo"

....

playd_start() {
playd_check # check if mplayer is running in slave mode

if [ "$?" -eq 0 ]; then # mplayer is not running
if [ "$1" = 'nobg' ]; then
exec $UTERM -geometry ${CONSOLE_GEOMETRY} -e ${MPLAYER_CMD} #run terminal and mplayer
echo "$!" > "$HOME/.playd.lock" #save pid to file1
#echo 'playd started'
else
exec ${MPLAYER_CMD} >> /dev/null & #run mplayer
echo "$!" > "$HOME/.playd.lock" #save pid to file1
#echo 'playd started'
fi
else # mplayer is running
if [ ! "$2" = 'silent' ]; then
echo 'playd seam to be running'
echo 'if not, try:'
echo " $(basename $0) restart"
fi
fi
}

[SirDice]

I want my perl script to fork mplayer, get it's pid, write to file, and continue to work like nothing happen :D
http://search.cpan.org/~nwclark/perl-5.8.9/pod/perlipc.pod#Complete_Dissociation_of_Child_from_Pa rent

[graudeejs]

http://search.cpan.org/~nwclark/perl-5.8.9/pod/perlipc.pod#Complete_Dissociation_of_Child_from_Pa rent

That's exactly same code like i have in "Programming Perl 3rd edition" (recently bought)

I will investigate carefully when i return from University in few hours