--- a/src/rcldb/rcldb.h
+++ b/src/rcldb/rcldb.h
@@ -83,6 +83,9 @@
     double       dbavgdoclen;
 };
 
+#ifdef IDX_THREADS
+extern  void *DbUpdWorker(void*);
+#endif // IDX_THREADS
 /**
  * Wrapper class for the native database.
  */
@@ -91,6 +94,9 @@
     // A place for things we don't want visible here.
     class Native;
     friend class Native;
+#ifdef IDX_THREADS
+    friend void *DbUpdWorker(void*);
+#endif // IDX_THREADS
 
     /* General stuff (valid for query or update) ****************************/
     Db(RclConfig *cfp);