diff --git a/libraries/libmdb/mdb.h b/libraries/libmdb/mdb.h
index 39d9b6f..30d4e92 100644
--- a/libraries/libmdb/mdb.h
+++ b/libraries/libmdb/mdb.h
@@ -84,12 +84,12 @@ typedef enum MDB_cursor_op {		/* cursor operations */
 /* return codes */
 /* BerkeleyDB uses -30800 to -30999, we'll go under them */
 #define MDB_SUCCESS	 0
-#define MDB_KEYEXIST	-30799		/* key/data pair already exists */
-#define MDB_NOTFOUND	-30798		/* key/data pair not found (EOF) */
-#define MDB_PAGE_NOTFOUND	-30797	/* Requested page not found */
-#define MDB_CORRUPTED	-30796		/* Located page was wrong type */
-#define MDB_PANIC		-30795		/* Update of meta page failed, probably I/O error */
-#define MDB_VERSION_MISMATCH	-30794	/* Environment version mismatch */
+#define MDB_KEYEXIST	(-30799)		/* key/data pair already exists */
+#define MDB_NOTFOUND	(-30798)		/* key/data pair not found (EOF) */
+#define MDB_PAGE_NOTFOUND	(-30797)	/* Requested page not found */
+#define MDB_CORRUPTED	(-30796)		/* Located page was wrong type */
+#define MDB_PANIC		(-30795)		/* Update of meta page failed, probably I/O error */
+#define MDB_VERSION_MISMATCH	(-30794)	/* Environment version mismatch */
 
 /* DB flags */
 #define MDB_REVERSEKEY	0x02		/* use reverse string keys */