ap_cnt
int ap_cnt(apd_t *);
apcnt = ap_cnt(a);
ASSERT(ap->ap_cnt > 0);
if (--(ap->ap_cnt) == 0)
ap_new->ap_cnt = 1;
ASSERT(ap->ap_cnt > 0);
if (--(ap->ap_cnt) == 0) {
ap_result->ap_cnt++;
int ap_cnt; /* in use count */