-#define GTK_FIXED(obj) (GTK_CHECK_CAST ((obj), GTK_TYPE_FIXED, GtkFixed))
-#define GTK_FIXED_CLASS(klass) (GTK_CHECK_CLASS_CAST ((klass), GTK_TYPE_FIXED, GtkFixedClass))
-#define GTK_IS_FIXED(obj) (GTK_CHECK_TYPE ((obj), GTK_TYPE_FIXED))
-#define GTK_IS_FIXED_CLASS(klass) (GTK_CHECK_CLASS_TYPE ((klass), GTK_TYPE_FIXED))
-
+#define GTK_FIXED(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GTK_TYPE_FIXED, GtkFixed))
+#define GTK_FIXED_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GTK_TYPE_FIXED, GtkFixedClass))
+#define GTK_IS_FIXED(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GTK_TYPE_FIXED))
+#define GTK_IS_FIXED_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GTK_TYPE_FIXED))
+#define GTK_FIXED_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GTK_TYPE_FIXED, GtkFixedClass))