<?php
class flockTest{
	public $file;
	public $fp;
	public $text;
	function __construct($file){
		$this->file=$file;
		$this->fp=fopen($this->file, "w+");
		$this->text='Here is the text.';
	}
	function flock_test(){
		if(flock($this->fp, LOCK_EX | LOCK_NB)){
			echo "Locked the file.<br/>";
			if(is_writable($this->file)){
				if(fwrite($his->fp, $this->text)==FALSE){
					throw new Exception("Can't write $this->file<br />");
				}
				else{
					echo "Created $this->file<br />";
				}
			}
			else{
				echo 'Write problem';
			}
			flock($this->fp, LOCK_UN);
			echo "Unlock the file.";
		}
		else{
			echo "Couldn't lock the file.";
		}
		fclose($this->fp);
	}
}
$testLock=new flockTest('lock.txt');
try{
	$testLock->flock_test();
}
catch(Exception $e){
	echo $e->getMessage();
}
?>