#!/usr/bin/perl
use strict;
use warnings;

my @result;
$SIG{ALRM} = sub {
    print "ALARM fired\n";
    die "timeout";
};

eval {
    alarm(3);
    @result = `sleep 5`;
    alarm(0);
};

print "Running after alarm: $@\n";

if ($@) {
    if ($@ =~ /timeout/i) {
      push @result, "App has hanged itself\n";
    } else {
        alarm(0);           # clear the still-pending alarm
        die;                # propagate unexpected exception
    } 
} 

print "result is: ", join('', @result), "\n";