#!/usr/bin/perl
use strict;
use warnings;
use Sem;
use Storable qw/lock_store lock_retrieve/;
use CGI;

my $q = new CGI;
my $sem = Sem->new('semaphore.txt');
my $x = lock_retrieve('k.dat') or die "Can't open k.dat: $!";
$x->{counter}++;
lock_store($x, 'k.dat') or die "Can't save k.dat: $!";
$sem->unlock;
print $q->header;