PHP file lock write

function file_write($file_name, $text, $mode='a', $timeout=30){
$handle = fopen($file_name, $mode);
while($timeout>0){
if ( flock($handle, LOCK_EX) ) {
$timeout--;
sleep(1);
}
}
if ( $timeout > 0 ){
fwrite($handle, $text.'\n');
flock($handle, LOCK_UN);
fclose($handle);
return true;
}
return false;
}

The handle operated by flock(int $handle, int $operation) function must be an open file pointer.

operation can be one of the following values:

To obtain a shared lock (reading program), set operation to LOCK_SH (set to 1 in versions prior to PHP 4.0.1).

To obtain an exclusive lock (writing program), set operation to LOCK_EX (set to 2 in versions prior to PHP 4.0.1).

To release a lock (whether shared or exclusive), set operation to LOCK_UN (set to 3 in versions prior to PHP 4.0.1).

If you don’t want flock() to block when locked, add LOCK_NB to operation (set to 4 in versions before PHP 4.0.1).