a = &afi[s->format];
ret = a->receiver->pre_select(rn, rfds, wfds, tv);
// PARA_NOTICE_LOG("%s preselect: %d\n", a->receiver->name, ret);
a = &afi[s->format];
ret = a->receiver->pre_select(rn, rfds, wfds, tv);
// PARA_NOTICE_LOG("%s preselect: %d\n", a->receiver->name, ret);