-#define GTK_PLUG(obj) (GTK_CHECK_CAST ((obj), GTK_TYPE_PLUG, GtkPlug))
-#define GTK_PLUG_CLASS(klass) (GTK_CHECK_CLASS_CAST ((klass), GTK_TYPE_PLUG, GtkPlugClass))
-#define GTK_IS_PLUG(obj) (GTK_CHECK_TYPE ((obj), GTK_TYPE_PLUG))
-#define GTK_IS_PLUG_CLASS(klass) (GTK_CHECK_CLASS_TYPE ((klass), GTK_TYPE_PLUG))
-#define GTK_PLUG_GET_CLASS(obj) (GTK_CHECK_GET_CLASS ((obj), GTK_TYPE_PLUG, GtkPlugClass))
+#define GTK_PLUG(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GTK_TYPE_PLUG, GtkPlug))
+#define GTK_PLUG_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GTK_TYPE_PLUG, GtkPlugClass))
+#define GTK_IS_PLUG(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GTK_TYPE_PLUG))
+#define GTK_IS_PLUG_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GTK_TYPE_PLUG))
+#define GTK_PLUG_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GTK_TYPE_PLUG, GtkPlugClass))