NL::File::Lock - File locking (based on lockfiles)

	use NL::File::Lock;

	# We will create locks for that file:
	my $filename = 'test_file.txt';

	# Writing all lockfiles to '/tmp' directory:
	&NL::File::Lock::init('/tmp');
	# If no 'NL::File::Lock::init' called - all lockfiles
	# will be at the same directorys as files

	# ---
	# Lock for writing (only one process can write)
	# 'timeout' - time to wait lock
	# 'time_sleep' - time to sleep between locking retrys
	if (&NL::File::Lock::lock_write($filename, { 'timeout' => 10, 'time_sleep' => 0.1 } )) {
		# File locked
		# ... code ...
		&NL::File::Lock::unlock($filename);
	}
	else {
		# Unable to lock file
	}

	# ---
	# Lock for reading (many processes can read)
	# 'timeout' - time to wait lock
	# 'time_sleep' - time to sleep between locking retrys
	if (&NL::File::Lock::lock_read($filename, { 'timeout' => 10, 'time_sleep' => 0.1 } )) {
		# File locked
		# ... code ...
		&NL::File::Lock::unlock($filename);
	}
	else {
		# Unable to lock file
	}

This module is used to easy and portable file locking.

	# ---
	# Lock for writing (only one process can write)
	my $filename = 'test_file.txt';
	# 'timeout' - time to wait lock
	# 'time_sleep' - time to sleep between locking retrys
	if (&NL::File::Lock::lock_write($filename, { 'timeout' => 10, 'time_sleep' => 0.1 } )) {
		print "+Locked EX (write)...\n";
		sleep(5);
		&NL::File::Lock::unlock_not_unlink($filename);
		print "-UnLocked for some time...\n";
		sleep(5);
		if (&NL::File::Lock::lock_write($filename, { 'timeout' => 10, 'time_sleep' => 0.1 } )) {
			print "+Locked EX (write)...\n";
			sleep(5);
			&NL::File::Lock::unlock($filename);
			print "-UnLocked forever...\n";
			sleep(5);
		}
		else { print "Unable to lock EX (write) again...\n"; }
	}
	else { print "Unable to lock EX (write)...\n"; }

	# ---
	# Lock for reading (many processes can read)
	my $filename = 'test_file.txt';
	# 'timeout' - time to wait lock
	# 'time_sleep' - time to sleep between locking retrys
	if (&NL::File::Lock::lock_read($filename, { 'timeout' => 10, 'time_sleep' => 0.1 } )) {
		print "+Locked SH (read)...\n";
		sleep(5);
		&NL::File::Lock::unlock_not_unlink($filename);
		print "-UnLocked for some time...\n";
		sleep(5);
		if (&NL::File::Lock::lock_read($filename, { 'timeout' => 10, 'time_sleep' => 0.1 } )) {
			print "+Locked SH (read)...\n";
			sleep(5);
			&NL::File::Lock::unlock($filename);
			print "-UnLocked forever...\n";
			sleep(5);
		}
		else { print "Unable to lock SH (read) agian...\n"; }
	}
	else { print "Unable to lock SH (read)...\n"; }

 Nickolay Kovalev, http://resume.nickola.ru
 Email: nickola_code@nickola.ru