diff --git a/valid.c b/valid.c
index de44a55..3235755 100644
--- a/valid.c
+++ b/valid.c
@@ -1628,6 +1628,7 @@
     if ((PublicID == NULL) && (SystemID == NULL)) {
         xmlGenericError(xmlGenericErrorContext,
 		"xmlAddNotationDecl: no PUBLIC ID nor SYSTEM ID\n");
+	return(NULL);
     }
 
     /*