how to know if php mail failed

Question

I am sending mails from php mail() : and I want to receive a failed message if sending is failed to the destinatio .

$to = '[email protected]';
    $email_from = "[email protected]";

    $full_name = 'XXXX';
    $from_mail = $full_name.'<'.$email_from.'>';



    $subject = "testing sender name";
    $message = "";
    $message .= '
            <p><strong>This is only a test mail. Please do not reply.</strong><br />
    ';
    $from = $from_mail;

    //$headers = "" .
    //         "Reply-To:" . $from . "\r\n" .
    //         "X-Mailer: PHP/" . phpversion();

    $headers = "From:" . $from_mail . "\r\n" .
               "Reply-To:" . $from_mail . "\r\n" .
               "X-Mailer: PHP/" . phpversion();


    $headers .= 'MIME-Version: 1.0' . "\r\n";
    $headers .= 'Content-type: text/html; charset=iso-8859-1' . "\r\n";        

    if(!mail($to,$subject,$message,$headers))
    {
        echo 'failed !!';
    }

But although $to mail does no exist,it is not showing failed !!

Answer 1

The mail method is just sending the mail out. If it does not receive any errors (e.g. by not finding the server etc), it will return succesfull. You will not be able to know if the mail actually landed in the inbox of the recipient unless you create some code around bounced emails etc.