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apply_filters_ref_array( string $hook_name, array $args ): mixed

Since
3.0.0
Source
wp-includes/plugin.php:228
Calls the callback functions that have been added to a filter hook, specifying arguments in an array.

Compatibility

WordPress
since 3.0.0
PHP
7.4–8.6-dev
  • 6.7.7
  • 6.8.8
  • 6.9.7
  • 7.0.4
  • 7.1.0

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

Parameters

$hook_namestring
The name of the filter hook.
$argsarray
The arguments supplied to the functions hooked to $hook_name.

Return value

mixed
The filtered value after all hooked functions are applied to it.

Performance profile

How much work a call to apply_filters_ref_array() 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
Trivial

Touches nothing outside its own arguments.

Scaling
Constant

No loop in the body: the same number of instructions runs whatever you pass in.

Instructions
17–36

Executed per call on PHP 8.5, depending on the branch taken. The body compiles to 45.

Plugin surface
None

Nothing here hands control to plugin code.

Called by
12

12 places in core call this, so the cost is paid more often than your own code shows.

What it touches

  • hookthird-party callbacksapply_filters_ref_array()this function does it

What one call costs · 6 distinct outcomes

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

WhenInstructionsCalls it makes
!isset($wp_filter) && !isset($wp_filter[$hook_name])17–18none
!isset($wp_filter[$hook_name])20–21array_pop()
!isset($wp_filter[$hook_name])23–24_wp_call_all_hook()
isset($wp_filter) && !isset($wp_filter[$hook_name])26–27_wp_call_all_hook(), array_pop()
!isset($wp_filter) && isset($wp_filter[$hook_name])27–30->apply_filters(), array_pop()
isset($wp_filter) && isset($wp_filter[$hook_name])33–36_wp_call_all_hook(), ->apply_filters(), array_pop()

Across PHP versions

Compiles the same on PHP 7.4, 8.1, 8.2, 8.3, 8.4, 8.5 and 8.6-dev: 45 instructions, 17–36 executed per call, 5 branches. The work does not change between versions.

An instruction is not a fixed amount of time, so a matching count is not necessarily the same speed; what it rules out is a difference in the work itself.

Uses · 1

Used by · 12

Source code

function apply_filters_ref_array( $hook_name, $args ) {	global $wp_filter, $wp_filters, $wp_current_filter; 	if ( ! isset( $wp_filters[ $hook_name ] ) ) {		$wp_filters[ $hook_name ] = 1;	} else {		++$wp_filters[ $hook_name ];	} 	// Do 'all' actions first.	if ( isset( $wp_filter['all'] ) ) {		$wp_current_filter[] = $hook_name;		$all_args            = func_get_args(); // phpcs:ignore PHPCompatibility.FunctionUse.ArgumentFunctionsReportCurrentValue.NeedsInspection		_wp_call_all_hook( $all_args );	} 	if ( ! isset( $wp_filter[ $hook_name ] ) ) {		if ( isset( $wp_filter['all'] ) ) {			array_pop( $wp_current_filter );		} 		return $args[0];	} 	if ( ! isset( $wp_filter['all'] ) ) {		$wp_current_filter[] = $hook_name;	} 	$filtered = $wp_filter[ $hook_name ]->apply_filters( $args[0], $args ); 	array_pop( $wp_current_filter ); 	return $filtered;}

Changelog

Introduced in 3.0.0. Unchanged from 6.7.7 through 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

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