Index: generic/gentclAPI.tcl
===================================================================
diff -u -rf1b65a9694a721be01a9a2acaff5ee093456b2bd -rf0295d889aaf71709c63243685897dc3f11048f1
--- generic/gentclAPI.tcl	(.../gentclAPI.tcl)	(revision f1b65a9694a721be01a9a2acaff5ee093456b2bd)
+++ generic/gentclAPI.tcl	(.../gentclAPI.tcl)	(revision f0295d889aaf71709c63243685897dc3f11048f1)
@@ -92,14 +92,14 @@
       set if [list "NsfClass *cl"]
       append intro \
           "  NsfClass *cl =  NsfObjectToClass(clientData);" \n \
-          {  if (!cl) return NsfObjErrType(interp, objv[0], "Class", "");}
+          {  if (!cl) return NsfObjErrType(interp, objv[0], "Class", NULL);}
     }
     object {
       set a  [list obj]
       set if [list "NsfObject *obj"]
       append intro \
           "  NsfObject *obj =  (NsfObject *)clientData;" \n \
-          {  if (!obj) return NsfObjErrType(interp, objv[0], "Object", "");}
+          {  if (!obj) return NsfObjErrType(interp, objv[0], "Object", NULL);}
     }
     ""    {
       set a [list]