do_action_ref_array( 'set_404', WP_Query $query ) Fires after a 404 is triggered. ContentsParameters Source Related Used By Changelog User Contributed Notes Parameters $query (WP_Query) The WP_Query instance (passed by reference). Top ↑Source File: wp-includes/class-wp-query.php View on Trac Top ↑Related Top ↑Used By Used By Used By Description wp-includes/class-wp-query.php: WP_Query::set_404() Sets the 404 property and saves whether query is feed. Top ↑Changelog Changelog Version Description 5.5.0 Introduced. Top ↑User Contributed Notes You must log in before being able to contribute a note or feedback.