cron hook

// Scheduled Action Hook
function wp_schedule_event( $param1 = 'get_jma_xml' ) {
}
add_action( 'wp_schedule_event', 'wp_schedule_event' );

// Schedule Cron Job Event
function custom_cron_job() {
	if ( ! wp_next_scheduled( 'wp_schedule_event' ) ) {
		wp_schedule_event( current_time( 'timestamp' ), 'hourly', 'wp_schedule_event', array( 'get_jma_xml' ) );
	}
}
add_action( 'wp', 'custom_cron_job' );