#!/usr/local/bin/perl -wT
# Flocking test
print "Content-type: text/html\n\n";

use Fcntl qw(:flock);
  my $file = 'test_lock.txt';
  my $SEMAPHORE = $file . '.lck';

  unless (-e "$file") {
    open(FILE,">$file") or die "Reason: $!";
    print FILE "1";
    close(FILE);
  }

  open(SEM, ">$SEMAPHORE") or die "$SEMAPHORE: $!";
  flock(SEM, LOCK_SH) or die "flock() failed for $SEMAPHORE: $!";
    open (FILE, "$file") or die "Can't open $file: $!";
    $count = <FILE>;
    close FILE;
  sleep 5;
  close SEM;

  $count++;

  open(S, ">$SEMAPHORE") or die "$SEMAPHORE: $!";
  flock(S, LOCK_EX) or die "flock() failed for $SEMAPHORE: $!";
    open (FH, ">$file") or die "Can't open $file: $!";
    print FH $count;
    close FH;
  sleep 5;
  close S;

  print "You have been here <B>$count</B> times!\n";