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From: worley@compass.uucp (Dale Worley)
Newsgroups: comp.lang.perl
Subject: How to do alarm()?
Message-ID: <1990Oct30.194343.27499@uvaarpa.Virginia.EDU>
Date: 30 Oct 90 19:43:43 GMT
Sender: mmdf@uvaarpa.Virginia.EDU (Uvaarpa Mail System)
Reply-To: worley@compass.uucp
Organization: The Internet
Lines: 25

Well, here's the code I use:

    #! /usr/local/bin/perl

    # Interval to re-read the information, in seconds
    $interval = 60;

    # Set the timer to go off in 1 second, and every $interval seconds
    # thereafter.  Call &get_info when it goes off.
    do '/compass/c/worley/perl-3.0/sys/syscall.h';
    $SIG{'ALRM'} = 'get_info';
    $value = pack('LLLL', $interval, 0, 1, 0);
    syscall(&SYS_setitimer, 0, $value, 0);

(Of course, you have to use the correct directory for your syscall.h
Perl header file.)  The crux of the problem is that alarm() isn't a
system call, it is a library routine that calls setitimer() (on BDS
4.2 systems, anyway).  You can do setitimer() pretty straightforwardly
using Perl's syscall().  Don't forget that the name of the signal is
ALRM, not ALARM!  (Elements of %SIG that don't correspond to real
signal names have no effect...)

Dale Worley		Compass, Inc.			worley@compass.com
--
I try to make everyone's day a little more surreal.