Source

File: wp-includes/cron.php

function wp_clear_scheduled_hook( $hook, $args = array() ) {
	// Backward compatibility.
	// Previously, this function took the arguments as discrete vars rather than an array like the rest of the API.
	if ( ! is_array( $args ) ) {
		_deprecated_argument( __FUNCTION__, '3.0.0', __( 'This argument has changed to an array to match the behavior of the other cron functions.' ) );
		$args = array_slice( func_get_args(), 1 ); // phpcs:ignore PHPCompatibility.FunctionUse.ArgumentFunctionsReportCurrentValue.NeedsInspection
	}

	/**
	 * Filter to preflight or hijack clearing a scheduled hook.
	 *
	 * Returning a non-null value will short-circuit the normal unscheduling
	 * process, causing the function to return the filtered value instead.
	 *
	 * For plugins replacing wp-cron, return the number of events successfully
	 * unscheduled (zero if no events were registered with the hook) or false
	 * if unscheduling one or more events fails.
	 *
	 * @since 5.1.0
	 *
	 * @param null|int|false $pre  Value to return instead. Default null to continue unscheduling the event.
	 * @param string         $hook Action hook, the execution of which will be unscheduled.
	 * @param array          $args Arguments to pass to the hook's callback function.
	 */
	$pre = apply_filters( 'pre_clear_scheduled_hook', null, $hook, $args );
	if ( null !== $pre ) {
		return $pre;
	}

	/*
	 * This logic duplicates wp_next_scheduled().
	 * It's required due to a scenario where wp_unschedule_event() fails due to update_option() failing,
	 * and, wp_next_scheduled() returns the same schedule in an infinite loop.
	 */
	$crons = _get_cron_array();
	if ( empty( $crons ) ) {
		return 0;
	}

	$results = array();
	$key     = md5( serialize( $args ) );
	foreach ( $crons as $timestamp => $cron ) {
		if ( isset( $cron[ $hook ][ $key ] ) ) {
			$results[] = wp_unschedule_event( $timestamp, $hook, $args );
		}
	}
	if ( in_array( false, $results, true ) ) {
		return false;
	}
	return count( $results );
}