diff -r f859d567f94e -r 42b62867574d master/domain.h
--- a/master/domain.h	Fri Jan 22 10:11:58 2016 +0100
+++ b/master/domain.h	Fri Jan 22 13:09:43 2016 +0100
@@ -72,6 +72,11 @@
                                              since last notification. */
     unsigned int redundancy_active; /**< Non-zero, if redundancy is in use. */
     unsigned long notify_jiffies; /**< Time of last notification. */
+    uint32_t offset_used[EC_DIR_COUNT]; /**< Next available domain offset of
+        PDO, by direction */
+    const ec_slave_config_t *sc_in_work; /**< slave_config which is actively
+        being registered in this domain
+        (i.e. ecrt_slave_config_reg_pdo_entry() ) */
 };
 
 /*****************************************************************************/