WordPress at a glance

wp_cron() WP 2.1.0

Run all scheduled cron events whose time has come.

Checks whether there is at least one cron event whose time has come, and runs spawn_cron() which send the request to cron file: /example.com/wp-cron.php.

When calling this function, all the cron events that were planned and which time has come will be initiated.

You can read more about cron in the description of wp_schedule_event() which is used to add new cron events. There are a lot of examples and everything you need to know about cron in WordPress.

This function called by WordPress core automatically on the init event.

if ( ! defined( 'DOING_CRON' ) ) {
	add_action( 'init', 'wp_cron' );
}

Basically, you don't need to use this function.

This function will not work, if constant DISABLE_WP_CRON is defined.

Cron is named after a unix program which runs unattended scheduled tasks.

Read more about cron: WP Cron (scheduler) in WordPress

Works based on: _wp_cron()

No Hooks.

Return

int/false.

  • Number — on success — the number of performed events (0 means that there are no events to be executed now).
  • false — when no event could be processed.

This function may return Boolean FALSE, but may also return a non-Boolean value which evaluates to FALSE. For information about casting to booleans see the PHP documentation. Use the === operator for testing the return value of this function.

Usage

wp_cron();

Examples

#1 Send an email every hour

You can place this code in, for example, functions.php.

// Schedule an event if it hasn't been scheduled yet
// It's better to do it during plugin/theme activation
if ( ! wp_next_scheduled( 'my_task_hook' ) ) {
	wp_schedule_event( time(), 'hourly', 'my_task_hook' );
}

// Add a callback
add_action( 'my_task_hook', 'my_task_function' );
function my_task_function() {
	wp_mail( 'your@email.com', 'Scheduled email', 'A scheduled email from  WordPress.');
}

#2 Add a cron event and a custom interval

The code must be added into the functions.php file or in plugin.

add_filter( 'cron_schedules', 'mycron_add_schedule' );
add_action( 'init', 'mycron_add_hook' );

## Schedules an event
function mycron_add_hook(){
	if ( ! wp_next_scheduled( 'my_cron_worker_start' ) ) { 
		wp_schedule_event( time(), 'my_cron_worker', 'my_cron_worker_start' ); 
	}
}

## Adds a custom interval
function mycron_add_schedule(){
	$schedules['my_cron_worker'] = array( 'interval' => 60, 'display' => 'My Cron Worker' );
	return $schedules;
}

Changelog

Since 2.1.0 Introduced.
Since 5.1.0 Return value added to indicate success or failure.
Since 5.7.0 Functionality moved to _wp_cron() to which this becomes a wrapper.

Code of wp_cron() WP 5.7.1

<?php
function wp_cron() {
	if ( did_action( 'wp_loaded' ) ) {
		return _wp_cron();
	}

	add_action( 'wp_loaded', '_wp_cron', 20 );
}

From tag: cron (schedule)

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