How to issue a 404 page if the page does not exist in cnc?

Question

PHP

If you go to a page on the site that does not exist, then Warning appears: call_user_func_array() expects parameter 1 to be a valid callback, class 'SiteController' does not have a method 'actionIndexasite'
in non-existent page, he got to the 404 page?

Answer 1

In general

header($_SERVER['SERVER_PROTOCOL'] . " 404 Not Found");

Answer 2

How do you select any page? Set the condition that if the selected page does not exist, then show the page such and such.