Simulate flock to implement file locking_PHP tutorial

// Lock a file , timing out if it takes too long.
function lock ($lock, $tries) {
$lock0 = ".{$lock}0";
$lock1 = ".{$lock}1 ";
for ($i=0; $i<$tries; $i++) {
if (!is_file($lock0)) {
touch($lock0);
if (! is_file($lock1)) {                                                                                                                                                                                                                           >} 

// Unlock a file. 
function unlock ($lock) { 
 unlink(".{$lock}1"); 
 unlink(".{$lock} 0");
}

// Usage example.
$filename = "somefile";
$data = "stuff and thingsn";
$tries = 10;
if (lock($filename, $tries)) {
$h = fopen($filename, "a") or die();
fwrite($h, $data);
fclose ($h);
/**
* Another process writes the file and checks whether it is locked
*/
if (lock($filename, $tries)) {
$h2 = fopen($filename, "a") or die() ;
fwrite($h2,'check lock');
fclose($h2);
}else{
//die("Failed to lock $ filename after ".($tries* 100)." milliseconds!";                                                                                              " milliseconds!";
}
?>