t_kspoll
if (error = t_kspoll(tiptr, 0, READWAIT, eventp)) {
error = t_kspoll(nbp->nbp_tiptr, timo, waitflg, &events);
if ((error = t_kspoll(tiptr, timo, READWAIT,
error = t_kspoll(tiptr, timo, READWAIT, &type);
extern int t_kspoll(TIUSER *, int, int, int *);