CODEWITHSUNDEEP
phpwordpress
Rvdrichard
Rvdrichard

Reputation: 335

I am not including any file in my theme then how wordpress functions are working

Something that I just can't understand is how the Wordpress functions are loaded in. When I am adding an action to a Wordpress hook like this.

 <?php

function test() {
echo "Test";
}

add_action('wp_enqueue_scripts','test');

?>

This code works for what I want to do but where is this add_action function coming from. I know Wordpress is taking care of it somehow but I just don't understand how I am able to call it without actually including a file. I tried to include the file in another file that would be included before this file but then I would get a function that is not defined error. I just really want to know the logic behind this.

Upvotes: 1

Views: 128

Answers (2)

Babbandeep Singh
Babbandeep Singh

Reputation: 95

It's work like, the first file that runs on open WordPress site is index.php which required wp-blog-header.php

/** Loads the WordPress Environment and Template */
 require( dirname( __FILE__ ) . '/wp-blog-header.php' );

then wp-blog-header.php require wp-load.php and template-loader.php

// Load the WordPress library.
require_once( dirname(__FILE__) . '/wp-load.php' );
// Set up the WordPress query.
wp();
// Load the theme template.
require_once( ABSPATH . WPINC . '/template-loader.php' );

here wp-load.php file require wp-config.php

if ( file_exists( ABSPATH . 'wp-config.php') ) {
   /** The config file resides in ABSPATH */
   require_once( ABSPATH . 'wp-config.php' );
}

and wp-config.php file require wp-settings.php

require_once(ABSPATH . 'wp-settings.php');

and wp-settings loads wp-includes/plugin.php file

define( 'WPINC', 'wp-includes' );
// Include files required for initialization.
require( ABSPATH . WPINC . '/load.php' );
require( ABSPATH . WPINC . '/default-constants.php' );
require_once( ABSPATH . WPINC . '/plugin.php' );

and wp-includes/plugin.php file have add_action function in it

function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
   return add_filter($tag, $function_to_add, $priority, $accepted_args);
}

and wp-includes/template-loader.php load the theme template.

require_once( ABSPATH . WPINC . '/template-loader.php' );

Upvotes: 1

Zach Broniszewski
Zach Broniszewski

Reputation: 252

You will find this function initialized in wp-includes/plugin.php :

function add_action($tag, $function_to_add, $priority = 10, $accepted_args = 1) {
    return add_filter($tag, $function_to_add, $priority, $accepted_args);
}

You can use the function wherever this file is included.

Wordpress has this documentation and more @ https://developer.wordpress.org/reference/functions/add_action/

Upvotes: 1

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