WP_Hook::has_filter( string $hook_name = '', callable|string|array|false $callback = false, int|false $priority = false ): bool|int

Description

Compatibility

Present in every tracked release (6.7.7 to 7.1.0), and compiles on PHP 7.4 through 8.6-dev.

Parameters

$hook_namestringoptional

The name of the filter hook. Default empty.Default: ''

$callbackcallable|string|array|falseoptional

The callback to check for.
This method can be called unconditionally to speculatively check a callback that may or may not exist. Default false.Default: false

$priorityint|falseoptional

The specific priority at which to check for the callback.
Default false.Default: false

Return value

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.

Performance profile

How much work a call to WP_Hook::has_filter() does, and what it touches: the algorithmic scaling, the Zend instruction count per call across PHP versions, the hooks it hands control to, and the core code that calls it. Measured from the compiled opcodes, not a stopwatch, so every number is identical on any machine running the same PHP version, and every function in core is ranked by cost.

Cost class

Light

Touches nothing outside its own arguments.

Scaling

Scales with input

The body loops, so the work grows with what you pass in.

Instructions

8–22

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 32.

Plugin surface

None

Nothing here hands control to plugin code.

Called by

0

Nothing in core calls this; the cost is only what you spend yourself.

What one call costs · 2 distinct outcomes

One number would be a lie: the work depends on which branch runs. These are every distinct cost WP_Hook::has_filter() can have, taken from its control-flow graph on PHP 8.5.

Uses · 2

• _wp_filter_build_unique_id()Builds a unique string ID for a hook callback function.
• WP_Hook::has_filters()Checks if any callbacks have been registered for this hook.

Source code

View on Trac ↗View on GitHub ↗

240	public function has_filter( $hook_name = '', $callback = false, $priority = false ) {241		if ( false === $callback ) {242			return $this->has_filters();243		}244 245		$function_key = _wp_filter_build_unique_id( $hook_name, $callback, false );246 247		if ( ! $function_key ) {248			return false;249		}250 251		if ( is_int( $priority ) ) {252			return isset( $this->callbacks[ $priority ][ $function_key ] );253		}254 255		foreach ( $this->callbacks as $callback_priority => $callbacks ) {256			if ( isset( $callbacks[ $function_key ] ) ) {257				return $callback_priority;258			}259		}260 261		return false;262	}

Changelog

Introduced in 4.7.0. One change between 6.7.7 and 7.1.0.

1. 6.7.7
2. 6.8.8
3. 6.9.7
4. 7.0.4
5. 7.1.0

Signature, return type and hooks compared across 5 parsed releases.

About this page

Parsed data

Generated from the wordpress-develop 6.9.7 tag, from src/wp-includes/class-wp-hook.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.

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