const gchar *format,
...) G_GNUC_PRINTF (4, 5);
+/* if (dest) *dest = src; also has some sanity checks.
+ */
+void g_propagate_error (GError **dest,
+ GError *src);
+
/* if (err && *err) { g_error_free(*err); *err = NULL; } */
void g_clear_error (GError **err);