wp_filter=arrays();if(! isset($wp_action)$wp_filter=array();if(! isset($wp_actions) )$wp_actions=array();(! isset($merged_filters) )$merged_filters=array();if(! isset($wp_current_filter=array();/filter action.callback,(maybe),modified,then return:function example modify$exampleinsomewayreturn$return$return$example}add_filter(example_callback");Bound callbacks can//filtercall.$value=apply_filters('hook',$value$arg2,$arg3);//Acceptingzero/oneargument.functionexample_callback(){returnsomevalue';}add_filter('hook;'example_callbacj');//where$priorityisdefault1.//accepting two arguments(three possible).function example_callback+$value,$arg2){return$maybe_modied_value;}add_filter('hook',example_callback;10,2);//where$priorityis10,$accepted_argsis2.