has_filter
has_filter ( $hook_name, $callback = false, $priority = false )
Parameters:- (string) hook_name The name of the filter hook.
- (callable|string|array|false) callback Optional. The callback to check for.
This function can be called unconditionally to speculatively check
a callback that may or may not exist. Default false.
- (int|false) priority Optional. The specific priority at which to check for the callback.
Default false.
Returns:- (bool|int) If `$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.
If `$callback` and `$priority` are both provided, a boolean is returned
for whether the specific function is registered at that priority.
Defined at:Change Log: - Introduced in WordPress: 2.5.0
- Deprecated in WordPress: —
Description
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.