Atomically appending a line to a file and creating it if it doesn't exist

Question

I\'m trying to create a function (for purposes of logging)

append($path, $data)

that

1. creates $file if it doesn\'t exist and

Answer 1

using PHP's internal function http://php.net/manual/en/function.file-put-contents.php

file_put_contents($file, $data, FILE_APPEND | LOCK_EX);

FILE_APPEND => flag to append the content to the end of the file

LOCK_EX => flag to prevent anyone else writing to the file at the same time (Available since PHP 5.1)