-#define GTK_SIZE_GROUP(obj) (GTK_CHECK_CAST ((obj), GTK_TYPE_SIZE_GROUP, GtkSizeGroup))
-#define GTK_SIZE_GROUP_CLASS(klass) (GTK_CHECK_CLASS_CAST ((klass), GTK_TYPE_SIZE_GROUP, GtkSizeGroupClass))
-#define GTK_IS_SIZE_GROUP(obj) (GTK_CHECK_TYPE ((obj), GTK_TYPE_SIZE_GROUP))
-#define GTK_IS_SIZE_GROUP_CLASS(klass) (GTK_CHECK_CLASS_TYPE ((klass), GTK_TYPE_SIZE_GROUP))
-#define GTK_SIZE_GROUP_GET_CLASS(obj) (GTK_CHECK_GET_CLASS ((obj), GTK_TYPE_SIZE_GROUP, GtkSizeGroupClass))
+#define GTK_SIZE_GROUP(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GTK_TYPE_SIZE_GROUP, GtkSizeGroup))
+#define GTK_SIZE_GROUP_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GTK_TYPE_SIZE_GROUP, GtkSizeGroupClass))
+#define GTK_IS_SIZE_GROUP(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GTK_TYPE_SIZE_GROUP))
+#define GTK_IS_SIZE_GROUP_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GTK_TYPE_SIZE_GROUP))
+#define GTK_SIZE_GROUP_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GTK_TYPE_SIZE_GROUP, GtkSizeGroupClass))