ib->t = t;
ib->nodes = (struct avlnode *)((unsigned char *)ib->nodes + diff);
ib->roots = (off_t *)((unsigned char *)ib->roots + diff);
ib->t = t;
ib->nodes = (struct avlnode *)((unsigned char *)ib->nodes + diff);
ib->roots = (off_t *)((unsigned char *)ib->roots + diff);