vb first = alloc (T_LINK); detach (first, list, LT_RIGHT, REDUCE_LIST);

vb first = alloc (T_LINK); detach (first, &list, LT_RIGHT, REDUCE_LIST);

vb first = alloc (T_LINK); detach (first, list, LT_RIGHT, REDUCE_LIST, ALLOW_EMPTY);

vb first = alloc (T_LINK); detach (first, &list, LT_RIGHT, REDUCE_LIST, ALLOW_EMPTY);