void output_item_unref (struct output_item *);
bool output_item_is_shared (const struct output_item *);
struct output_item *output_item_unshare (struct output_item *);
void output_item_unref (struct output_item *);
bool output_item_is_shared (const struct output_item *);
struct output_item *output_item_unshare (struct output_item *);