<tag>

Hooks a function on to a specific action.

Description

add_filter( '<tag>', (unknown) $function_to_add, (unknown) $priority, (unknown) $accepted_args ); 

Actions are the hooks that the WordPress core launches at specific points during execution, or when specific events occur. Plugins can specify that one or more of its PHP functions are executed at these points, using the Action API.

Parameters (3)

0. $function_to_add (unknown)
The function to add.
1. $priority (unknown)
The priority.
2. $accepted_args (unknown)
The accepted args.

Usage

To run the hook, copy the example below.
  1. $function_to_add = apply_filters( '{$tag}', $function_to_add, $priority, $accepted_args ); 
  2.  
  3. if ( !empty( $function_to_add ) ) { 
  4.  
  5. // everything has led up to this point... 
  6.  
  7.  
The following example is for adding a hook callback.
  1. // define the <tag> callback 
  2. function filter_tag( $function_to_add, $priority, $accepted_args ) { 
  3. // make filter magic happen here... 
  4. return $function_to_add
  5. }; 
  6.  
  7. // add the filter 
  8. add_filter( "{$tag}", 'filter_tag', 10, 3 ); 
To remove a hook callback, use the example below.
  1. // remove the filter 
  2. remove_filter( "{$tag}", 'filter_tag', 10, 3 ); 

Defined (1)

The filter is defined in the following location(s).

/wp-includes/plugin.php  
  1. return add_filter($tag, $function_to_add, $priority, $accepted_args);