do_action( string $tag, mixed $arg )

Execute functions hooked on a specific action hook.


Description Description

This function invokes all functions attached to action hook $tag. It is possible to create new action hooks by simply calling this function, specifying the name of the new hook using the $tag parameter.

You can pass extra arguments to the hooks, much like you can with apply_filters().

Example usage:

// The action callback function
function example_callback( $arg1, $arg2 ) {
    // (maybe) do something with the args
}
add_action( 'example_action', 'example_callback', 10, 2 );

/*
 * Trigger the actions by calling the 'example_callback()' function that's
 * hooked onto `example_action` above.
 *
 * - 'example_action' is the action hook
 * - $arg1 and $arg2 are the additional arguments passed to the callback.
$value = do_action( 'example_action', $arg1, $arg2 );

Parameters Parameters

$tag

(string) (Required) The name of the action to be executed.

$arg

(mixed) (Optional) Additional arguments which are passed on to the functions hooked to the action. Default empty.


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Source Source

File: wp-includes/plugin.php

function do_action( $tag, ...$arg ) {
	global $wp_filter, $wp_actions, $wp_current_filter;

	if ( ! isset( $wp_actions[ $tag ] ) ) {
		$wp_actions[ $tag ] = 1;
	} else {
		++$wp_actions[ $tag ];
	}

	// Do 'all' actions first
	if ( isset( $wp_filter['all'] ) ) {
		$wp_current_filter[] = $tag;
		$all_args            = func_get_args();
		_wp_call_all_hook( $all_args );
	}

	if ( ! isset( $wp_filter[ $tag ] ) ) {
		if ( isset( $wp_filter['all'] ) ) {
			array_pop( $wp_current_filter );
		}
		return;
	}

	if ( ! isset( $wp_filter['all'] ) ) {
		$wp_current_filter[] = $tag;
	}

	if ( empty( $arg ) ) {
		$arg[] = '';
	} elseif ( is_array( $arg[0] ) && 1 === count( $arg[0] ) && isset( $arg[0][0] ) && is_object( $arg[0][0] ) ) {
		// Backward compatibility for PHP4-style passing of `array( &$this )` as action `$arg`.
		$arg[0] = $arg[0][0];
	}

	$wp_filter[ $tag ]->do_action( $arg );

	array_pop( $wp_current_filter );
}

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Changelog Changelog

Changelog
Version Description
5.3.0 Formalized the existing and already documented ...$arg parameter by adding it to the function signature.
1.2.0 Introduced.