EV__IOFDSET
if (anfd->reify & EV__IOFDSET && anfd->head)
o_reify = EV__IOFDSET; /* actually |= */
if (o_reify & EV__IOFDSET)
fd_change (EV_A_ fd, EV__IOFDSET | EV_ANFD_REIFY);
assert (("libev: ev_io_start called with illegal event mask", !(w->events & ~(EV__IOFDSET | EV_READ | EV_WRITE))));
fd_change (EV_A_ fd, w->events & EV__IOFDSET | EV_ANFD_REIFY);
w->events &= ~EV__IOFDSET;
#define ev_io_set(ev,fd_,events_) do { (ev)->fd = (fd_); (ev)->events = (events_) | EV__IOFDSET; } while (0)