CHT_FIRST
iter->_next = CHT_FIRST(&ctl->nh_head, iter->_i);
nh_priv = CHT_FIRST(&ctl->nh_head, iter->_i);
_ret = CHT_FIRST(_head, _buck); \
_PX##_next(_obj) = CHT_FIRST(_head, _buck); \
CHT_FIRST(_head, _buck) = _obj; \
_ret = CHT_FIRST(_head, _buck); \
CHT_FIRST(_head, _buck) = _PX##_next(_ret); \
for (_x = CHT_FIRST(_head, _i); _x; _x = _PX##_next(_x))
for (_x = CHT_FIRST(_head, _i); (_tmp = _PX##_next(_x), _x); _x = _tmp)
_x = CHT_FIRST(_head, _old_idx); \
_ret = CHT_FIRST(_head, _buck); \