elgg_validate_registration_data($username, $password, $name, $email, $allow_multiple_emails=false)
Assert that given registration details are valid and can be used to register the user.
elgg_echo($message_key, array $args=[], $language="")
Elgg language module Functions to manage language and translations.
elgg_error_response($message= '', $forward_url=REFERRER, int $status_code=ELGG_HTTP_BAD_REQUEST)
Prepare an error response to be returned by a page or an action handler.
elgg_ok_response($content= '', $message= '', $forward_url=null, int $status_code=ELGG_HTTP_OK)
Prepares a successful response to be returned by a page or an action handler.