-#define GTK_VIEWPORT(obj) GTK_CHECK_CAST (obj, gtk_viewport_get_type (), GtkViewport)
-#define GTK_VIEWPORT_CLASS(klass) GTK_CHECK_CLASS_CAST (klass, gtk_viewport_get_type (), GtkViewportClass)
-#define GTK_IS_VIEWPORT(obj) GTK_CHECK_TYPE (obj, gtk_viewport_get_type ())
+#define GTK_TYPE_VIEWPORT (gtk_viewport_get_type ())
+#define GTK_VIEWPORT(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GTK_TYPE_VIEWPORT, GtkViewport))
+#define GTK_VIEWPORT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GTK_TYPE_VIEWPORT, GtkViewportClass))
+#define GTK_IS_VIEWPORT(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GTK_TYPE_VIEWPORT))
+#define GTK_IS_VIEWPORT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GTK_TYPE_VIEWPORT))
+#define GTK_VIEWPORT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GTK_TYPE_VIEWPORT, GtkViewportClass))