Mail() function and additional parameters

Hi,

How can i use PHP mail() function to send additional parameter besides “to”, “subject” and “message” fields:

<?php

$subject = 'subject';
$toAddress = 'toaddress';
$message = 'message';

(mail($toAddress, $subject, $message))
?>

Let’s say i want to also send:


$url = 'some url';

variable value but i am not sure how to do that?