bug#50043: 28.0.50; USABLE_SIGOI undef code paths do not work correctly

[Ken Brown]

On 11/17/2021 2:41 AM, Lars Ingebrigtsen wrote:
> Ken Brown <kbrown@cornell.edu> writes:
>
> > Namely, whenever wait_reading_process_output is polling for input,
> > avoid getting stuck in select, something like this:
>
> [...]
>
> > +#ifndef USABLE_SIGIO
> > +         /* If we're polling for input, don't get stuck in select for
> > +            more than 25 msec. */
> > +         struct timespec short_timeout = make_timespec (0, 25000000);
> > +         if ((read_kbd || !NILP (wait_for_cell))
> > +             && timespec_cmp (short_timeout, timeout) < 0)
> > +           timeout = short_timeout;
> > +#endif
>
> Sounds like a good general solution to me (but I guess this will also
> affect `accept-process-output'?  So it should probably be documented
> there).

I don't think it affects accept-process-output.  When the latter calls 
wait_reading_process_output, read_kbd == 0 and wait_for_cell == Qnil.

Ken