has_filter( string $tag, callable|bool $function_to_check = false )
Check if any filter has been registered for a hook.
Parameters
- $tag
-
(Required) The name of the filter hook.
- $function_to_check
-
(Optional) The callback to check for.
Default value: false
Return
(false|int) If $function_to_check is omitted, returns boolean for whether the hook has anything registered. When checking a specific function, the priority of that hook is returned, or false if the function is not attached. When using the $function_to_check argument, this function may return a non-boolean value that evaluates to false (e.g.) 0, so use the === operator for testing the return value.
Source
File: wp-includes/plugin.php
function has_filter($tag, $function_to_check = false) {
global $wp_filter;
if ( ! isset( $wp_filter[ $tag ] ) ) {
return false;
}
return $wp_filter[ $tag ]->has_filter( $tag, $function_to_check );
}
Changelog
| Version | Description |
|---|---|
| WP-2.5.0 | Introduced. |