* @param int $timestamp Timestamp for when to run the event.
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
+ * @return void|false
*/
function wp_schedule_single_event( $timestamp, $hook, $args = array()) {
// don't schedule a duplicate if there's already an identical event due within 10 minutes of it
* @param string $recurrence How often the event should recur.
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
- * @return false|null False on failure, null when complete with scheduling event.
+ * @return false|void False when does not schedule event.
*/
function wp_schedule_event( $timestamp, $recurrence, $hook, $args = array()) {
$crons = _get_cron_array();
* @param string $recurrence How often the event should recur.
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
- * @return false|null False on failure. Null when event is rescheduled.
+ * @return false|void False when does not schedule event.
*/
function wp_reschedule_event( $timestamp, $recurrence, $hook, $args = array() ) {
$crons = _get_cron_array();
*
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
- * @return bool|int The UNIX timestamp of the next time the scheduled event will occur.
+ * @return false|int The UNIX timestamp of the next time the scheduled event will occur.
*/
function wp_next_scheduled( $hook, $args = array() ) {
$crons = _get_cron_array();
* Send request to run cron through HTTP request that doesn't halt page loading.
*
* @since 2.1.0
- *
- * @return null Cron could not be spawned, because it is not needed to run.
*/
function spawn_cron( $gmt_time = 0 ) {
-
if ( ! $gmt_time )
$gmt_time = microtime( true );
return;
/*
- * multiple processes on multiple web servers can run this code concurrently
- * try to make this as atomic as possible by setting doing_cron switch
- */
+ * Get the cron lock, which is a unix timestamp of when the last cron was spawned
+ * and has not finished running.
+ *
+ * Multiple processes on multiple web servers can run this code concurrently,
+ * this lock attempts to make spawning as atomic as possible.
+ */
$lock = get_transient('doing_cron');
if ( $lock > $gmt_time + 10 * MINUTE_IN_SECONDS )
return;
}
+ // Set the cron lock with the current unix timestamp, when the cron is being spawned.
$doing_wp_cron = sprintf( '%.22F', $gmt_time );
set_transient( 'doing_cron', $doing_wp_cron );
* Run scheduled callbacks or spawn cron for all scheduled events.
*
* @since 2.1.0
- *
- * @return null When doesn't need to run Cron.
*/
function wp_cron() {
-
// Prevent infinite loops caused by lack of wp-cron.php
if ( strpos($_SERVER['REQUEST_URI'], '/wp-cron.php') !== false || ( defined('DISABLE_WP_CRON') && DISABLE_WP_CRON ) )
return;
*
* @param string $hook Action hook to execute when cron is run.
* @param array $args Optional. Arguments to pass to the hook's callback function.
- * @return string|bool False, if no schedule. Schedule on success.
+ * @return string|false False, if no schedule. Schedule on success.
*/
function wp_get_schedule($hook, $args = array()) {
$crons = _get_cron_array();
* @since 2.1.0
* @access private
*
- * @return array CRON info array.
+ * @return false|array CRON info array.
*/
function _get_cron_array() {
$cron = get_option('cron');