apply_filters() – Calls the callback functions that have been added to a filter hook.
You appear to be a bot. Output may be restricted
Description
Calls the callback functions that have been added to a filter hook.
This function invokes all functions attached to filter hook `$hook_name`. It is possible to create new filter hooks by simply calling this function, specifying the name of the new hook using the $hook_name
parameter.
The function also allows for multiple additional arguments to be passed to hooks.
Example usage:
- // The filter callback function.
- function example_callback( $string, $arg1, $arg2 ) {
- // (maybe) modify $string.
- return $string;
- }
- add_filter( 'example_filter', 'example_callback', 10, 3 );
- /*
- Apply the filters by calling the 'example_callback()' function
- that's hooked onto
example_filter
above. - 'example_filter' is the filter hook.
- 'filter me' is the value being filtered.
- $arg1 and $arg2 are the additional arguments passed to the callback.
- $value = apply_filters( 'example_filter', 'filter me', $arg1, $arg2 );
Usage
$mixed = apply_filters( $hook_name, $value, $args );
Parameters
- $hook_name
- ( string ) required – The name of the filter hook.
- $value
- ( mixed ) required – The value to filter.
- $args
- ( mixed ) optional –
Returns
mixed The filtered value after all hooked functions are applied to it.
Source
File name: wordpress/wp-includes/plugin.php
Lines:
function apply_filters( $hook_name, $value, ...$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 $value; } if ( ! isset( $wp_filter['all'] ) ) { $wp_current_filter[] = $hook_name; } // Pass the value to WP_Hook. array_unshift( $args, $value ); $filtered = $wp_filter[ $hook_name ]->apply_filters( $value, $args ); array_pop( $wp_current_filter ); return $filtered; }