wp-includes/cron.php:39Schedules an event to run only once.
$timestampint$hookstring$argsarrayoptionalarray()$wp_errorbooloptionalfalsebool|WP_Error2 hooks fire while wp_schedule_single_event() runs, in this order:
Filter to override scheduling an event.
Modify an event before it is scheduled.
function wp_schedule_single_event( $timestamp, $hook, $args = array(), $wp_error = false ) { // Make sure timestamp is a positive integer. if ( ! is_numeric( $timestamp ) || $timestamp <= 0 ) { if ( $wp_error ) { return new WP_Error( 'invalid_timestamp', __( 'Event timestamp must be a valid Unix timestamp.' ) ); } return false; } $event = (object) array( 'hook' => $hook, 'timestamp' => $timestamp, 'schedule' => false, 'args' => $args, ); /** * Filter to override scheduling an event. * * Returning a non-null value will short-circuit adding the event to the * cron array, causing the function to return the filtered value instead. * * Both single events and recurring events are passed through this filter; * single events have `$event->schedule` as false, whereas recurring events * have this set to a recurrence from wp_get_schedules(). Recurring * events also have the integer recurrence interval set as `$event->interval`. * * For plugins replacing wp-cron, it is recommended you check for an * identical event within ten minutes and apply the {@see 'schedule_event'} * filter to check if another plugin has disallowed the event before scheduling. * * Return true if the event was scheduled, false or a WP_Error if not. * * @since 5.1.0 * @since 5.7.0 The `$wp_error` parameter was added, and a `WP_Error` object can now be returned. * * @param null|bool|WP_Error $result The value to return instead. Default null to continue adding the event. * @param object $event { * An object containing an event's data. * * @type string $hook Action hook to execute when the event is run. * @type int $timestamp Unix timestamp (UTC) for when to next run the event. * @type string|false $schedule How often the event should subsequently recur. * @type array $args Array containing each separate argument to pass to the hook's callback function. * @type int $interval Optional. The interval time in seconds for the schedule. Only present for recurring events. * } * @param bool $wp_error Whether to return a WP_Error on failure. */ $pre = apply_filters( 'pre_schedule_event', null, $event, $wp_error ); if ( null !== $pre ) { if ( $wp_error && false === $pre ) { return new WP_Error( 'pre_schedule_event_false', __( 'A plugin prevented the event from being scheduled.' ) ); } if ( ! $wp_error && is_wp_error( $pre ) ) { return false; } return $pre; } /* * Check for a duplicated event. * * Don't schedule an event if there's already an identical event * within 10 minutes. * * When scheduling events within ten minutes of the current time, * all past identical events are considered duplicates. * * When scheduling an event with a past timestamp (ie, before the * current time) all events scheduled within the next ten minutesIntroduced in 2.1.0. Unchanged from 6.7.7 through 7.1.0.
Signature, return type and hooks compared across 5 parsed releases.
src/wp-includes/cron.php, and regenerated for each WordPress release so it tracks the code rather than a snapshot of it.