# subroutine name: getcounter
# Reads content of a counter file and returns an integer.
# If counter file doesn't exist, returns "0".
# If error occurs, makes CGI process exit with error
#
# Global variables used:
#	$no_flock - disable flock or not
sub getcounter {
	my($datafile) = @_;
	my $count=0;
	if (-f $datafile) {
		# If OS (like Win95) desn't support flock, we have to
		# go unreliable and slow way and create "lock" file
		GetFileLock("$datafile.lock");
		if (open (COUNTER, "<$datafile")) {
			# shared locking
			flock(COUNTER, 1) unless ($no_flock);
			$count = int <COUNTER> || 0;
			# unlock file
			flock(COUNTER, 8) unless ($no_flock);
			close(COUNTER);
			ReleaseFileLock("$datafile.lock");
		} else {
	  		ReleaseFileLock("$datafile.lock");
			die("Error in subroutine getcounter: Can't open $datafile. Reason: $!");
		}
	};
	return $count;
}