END_OF_HCHAIN
(bn) != END_OF_HCHAIN(h); (bn) = (bn)->hnext)
(bn)->hprev = END_OF_HCHAIN(h); \
if (bn == END_OF_HCHAIN(h)) {
thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h);
thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h);