Apache::Registry normally assumes a return code of OK (200) and sends it for you. If a different return code needs to be sent, $r->status( ) can be used. For example, to send the return code 404 (Not Found), you can use the following code:

use Apache::Constants qw(NOT_FOUND);
$r->status(NOT_FOUND);

If this method is used, there is no need to call $r->send_http_header( ) (assuming that the PerlSendHeader Offsetting is in effect).