--- PApp-SQL/SQL.xs	2000/10/21 19:00:53	1.1
+++ PApp-SQL/SQL.xs	2000/10/24 04:21:45	1.2
@@ -2,7 +2,7 @@
 #include "perl.h"
 #include "XSUB.h"
 
-#define is_dbh(sv) (sv && SvROK (sv) && sv_derived_from (sv, "DBI::db"))
+#define is_dbh(sv) ((sv) && sv_isobject (sv) && sv_derived_from ((sv), "DBI::db"))
 
 typedef struct lru_node {
   struct lru_node *next;