+/* Header code */
+gint _gtk_tree_data_list_compare_func (GtkTreeModel *model,
+ GtkTreeIter *a,
+ GtkTreeIter *b,
+ gpointer user_data);
+GList * _gtk_tree_data_list_header_new (gint n_columns,
+ GType *types);
+void _gtk_tree_data_list_header_free (GList *header_list);
+GtkTreeDataSortHeader *_gtk_tree_data_list_get_header (GList *header_list,
+ gint sort_column_id);
+GList *_gtk_tree_data_list_set_header (GList *header_list,
+ gint sort_column_id,
+ GtkTreeIterCompareFunc func,
+ gpointer data,
+ GDestroyNotify destroy);