Timers and timer expire handlers

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

Revered Monks,
My Active Perl script has the following structure:

while(some condition)
{
some operations;
sleep 300;
}

Now I need the script to perform a certain operation at exactly 4:00pm everyday and then exit.
Is there some timer mechanism in perl which lets me define a timer and also lets me define a timer expiry handler which gets executed when the timer expires?
Is there a differentway of doing this other than using timers?

Greatly appreciate any help here.
Thanks

Comment on Timers and timer expire handlers

Replies are listed 'Best First'.
Re: Timers and timer expire handlers by Corion (Patriarch) on Mar 27, 2006 at 20:38 UTC
You want to schedule your script via the `cron` daemon. It can launch your script at predefined times conveniently. The cron manpage has information on how to do this. If `cron` is not available on your system, there is Schedule::Cron, with which you can write your own small implementation of `cron` to launch your program at specific times. For the expiry timer, set up an alarm handler for `$SIG{ALRM}`, and prime it with `alarm(300)` or however many seconds you want to give your program: `eval { local $SIG{ALRM} = sub { die "alarm\n" }; # NB: \n required alarm $timeout; $nread = sysread SOCKET, $buffer, $size; alarm 0; }; if ($@) { die unless $@ eq "alarm\n"; # propagate unexpected errors # timed out } else { # didn't }` [download]	[reply] [d/l] [select]
Re^2: Timers and timer expire handlers by narashima (Beadle) on Mar 27, 2006 at 22:09 UTC
Corion, thanks for the reply. However I am running this on Active state perl on Windows NT. Unfortunately my version of Activestate does not support Schedule::cron and cron itself is not available. Access to Windows scheduler is disabled at group level. Please help. Thanks, Bhavin	[reply]
Re^3: Timers and timer expire handlers by Corion (Patriarch) on Mar 28, 2006 at 06:11 UTC
If you're running ActiveState Perl on Windows, there is my module Schedule::Cron::Nofork, which relies on Schedule::Cron. I use it on Windows without problems. To install the two modules Schedule::Cron and Schedule::Cron::Nofork, see the following nodes: Installing modules on Win32 A Guide to Installing Modules A guide to installing modules for Win32	[reply]
Re^4: Timers and timer expire handlers by narashima (Beadle) on Mar 28, 2006 at 14:06 UTC
Re: Timers and timer expire handlers by mda2 (Hermit) on Mar 28, 2006 at 00:51 UTC
You can make a cron-like process using a relative sleep... Start your script with wperl.exe, running without console (check Daemonize process). I ran a similar code, started with wperl.exe, at W2K without problems (except reboot or admin changes) ... Read more... (578 Bytes) -- Marco Antonio Rio-PM	[reply] [d/l]