+#if GTK_CHECK_VERSION(2,0,0)
+ASSERT(sizeof(long) <= sizeof(gsize));
+#define LONG_TO_GPOINTER(l) GSIZE_TO_POINTER(l)
+#define GPOINTER_TO_LONG(p) GPOINTER_TO_SIZE(p)
+#else /* Gtk 1.2 */
+ASSERT(sizeof(long) <= sizeof(gpointer));
+#define LONG_TO_GPOINTER(l) ((gpointer)(long)(l))
+#define GPOINTER_TO_LONG(p) ((long)(p))
+#endif
+