--- Curses-1.06/Curses.c.orig	Tue Jul 30 02:42:30 2002
+++ Curses-1.06/Curses.c	Tue Jul 30 03:09:25 2002
@@ -272,7 +272,7 @@
 SV *sv;
 int argnum;
 {
-    if (Perl_sv_isa(sv, "Curses::Window")) {
+    if (sv_isa( sv, "Curses::Window")) {
       WINDOW *ret = (WINDOW *)SvIV((SV*)SvRV(sv));
       return ret;

     }