-#define GTK_ACCESSIBLE(obj) (GTK_CHECK_CAST ((obj), GTK_TYPE_ACCESSIBLE, GtkAccessible))
-#define GTK_ACCESSIBLE_CLASS(klass) (GTK_CHECK_CLASS_CAST ((klass), GTK_TYPE_ACCESSIBLE, GtkAccessibleClass))
-#define GTK_IS_ACCESSIBLE(obj) (GTK_CHECK_TYPE ((obj), GTK_TYPE_ACCESSIBLE))
-#define GTK_IS_ACCESSIBLE_CLASS(klass) (GTK_CHECK_CLASS_TYPE ((klass), GTK_TYPE_ACCESSIBLE))
-#define GTK_ACCESSIBLE_GET_CLASS(obj) (GTK_CHECK_GET_CLASS ((obj), GTK_TYPE_ACCESSIBLE, GtkAccessibleClass))
-
-typedef struct _GtkAccessible GtkAccessible;
-typedef struct _GtkAccessibleClass GtkAccessibleClass;
+#define GTK_ACCESSIBLE(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GTK_TYPE_ACCESSIBLE, GtkAccessible))
+#define GTK_ACCESSIBLE_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GTK_TYPE_ACCESSIBLE, GtkAccessibleClass))
+#define GTK_IS_ACCESSIBLE(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GTK_TYPE_ACCESSIBLE))
+#define GTK_IS_ACCESSIBLE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GTK_TYPE_ACCESSIBLE))
+#define GTK_ACCESSIBLE_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GTK_TYPE_ACCESSIBLE, GtkAccessibleClass))