#!/usr/bin/perl -w
use strict;
#$|=1; #see note below...

$SIG{'ALRM'} = 'timeout';

alarm(1);
while (1){sleep(1);} 

sub timeout
{
    print        "stdout: Alarming!\n";
    print STDERR "stderr: Alarming!\n";
    exit(0);
};
__END__
prints:
   Note: stderr msg comes first because "autoflush" for
   stdout wasn't turned on (stdout normally doesn't
   get "flushed" until program end). 
   $|=1; turns autoflush on.

stderr: Alarming!
stdout: Alarming!