mail() function

[hermes]

This is a Q about the mail() function in PHP

I want to send an email to multiple recipients. As I understand it:

It is possible to send an email to multiple recipients with a single call to the mail() function. Here is an example. All you need to do is modify
the recipient variable as follows:

$to = "[e-mail], [e-mail]";

In other words, simply separate each required recipient by a comma.

Seems simple enough. I guess that the above code is equivalent to some other syntax that I have seen out there for sending
email to multiple recipients:

$to = "[e-mail]" . ", " ; // note the comma
$to .= "[e-mail]";

Am I right in this?

Then there is some other syntax that I have seen for sending email to multiple recipiants:

The part of the code below that I am referring to is the part with Cc and Bcc. Am I right in saying that this code will send emails to:

[e-mail]
[e-mail]
[e-mail]
[e-mail]

With [e-mail] being sent blind. The other recipiants do not know that this message has been sent to this email address?

<?php
/* recipients */
$to = "[e-mail]" . ", " ; // note the comma
$to .= "[e-mail]";

/* subject */
$subject = "Birthday Reminders for August";

/* message */
$message = 'jhguguguygj';

/* headers */
$headers .= "To: Mary <[e-mail]>, Kelly <[e-mail]>\r\n";
$headers .= "From: Birthday Reminder <[e-mail]>\r\n";
$headers .= "Cc: [e-mail]\r\n";
$headers .= "Bcc: [e-mail]\r\n";

/* and now mail it */
mail($to, $subject, $message, $headers);
?>

In short - are the 3 coding methodologies for sending email to multiple recipiants that I have listed here all valid? Many thanks.

[demnetia]

Indeed.