It might help to see some code, especially since you are passing file handles around...

Also, if you have access to strace you can use it to track down where the file is being closed and where you are loosing your lock.

strace -f perl file.pl

The -f will tell it to keep tracing if the program forks. Look for any close() calls that look out of position.

I was actually working on a similar program yesterday, using the Proc::Daemon module which does the backgrounding for you, and the Proc::PID::File to generate pid files.

use Proc::Daemon;
use Proc::PID::File;

Proc::Daemon::Init;

my $pf = new Proc::PID::File(dir => '/tmp');
die "Already running!" if $pf->alive();

# Child code goes here

[download]

This will daemonize the process and create a pid file for you. Probably not exatcly what you are looking for, but might give you some hints.

In reply to Re: Keeping File Locks after Daemonization by cees
in thread Keeping File Locks after Daemonization by SIGSEGV

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