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has_filter › WordPress Function

has_filter ( $hook_name, $callback = false )
Parameters: (2)
  • (string) $hook_name The name of the filter hook.
    Required: Yes
  • (callable|string|array|false) $callback Optional. The callback to check for. This function can be called unconditionally to speculatively check a callback that may or may not exist. Default false.
    Required: No
    Default: false
  • (bool|int) If `$callback` 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.
Defined at:

Checks if any filter has been registered for a hook.

When using the $callback 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.


function has_filter( $hook_name, $callback = false ) {
	global $wp_filter;

	if ( ! isset( $wp_filter[ $hook_name ] ) ) {
		return false;

	return $wp_filter[ $hook_name ]->has_filter( $hook_name, $callback );