diff --git a/tools/libs/store/include/xenstore.h b/tools/libs/store/include/xenstore.h
index 158e69ef83..2b3f69fb61 100644
--- a/tools/libs/store/include/xenstore.h
+++ b/tools/libs/store/include/xenstore.h
@@ -23,6 +23,7 @@
 
 #define XBT_NULL 0
 
+/* Following open flags are deprecated and ignored! */
 #define XS_OPEN_READONLY	(1UL<<0)
 #define XS_OPEN_SOCKETONLY      (1UL<<1)