Re: Waiting for 'high priority' events with kqueue

[Daurnimator <quae%daurnimator.com@localhost>]

On 12 June 2015 at 02:12, Christos Zoulas <christos%zoulas.com@localhost> wrote:
> In article <CAEnbY+f0PC=bvB2o+Y5ndFNK5HVP8tbQMzYdR2a7paQAxMxvPw%mail.gmail.com@localhost> you write:
>>Hi,
>>
>>I'm working on adding support for "high priority" events to a user
>>space event library.
>>Conceptually, I need the equivalent of poll() with POLLPRI, but via kqueue.
>>
>>FreeBSD and Apple OSX provide this via the 'EV_OOBAND' flag to EV_SET.
>>However, NetBSD (and OpenBSD) do not.
>>
>>Is there a way to wait for "high priority" events with kqueue on NetBSD?
>>I had a read through various kernel sources, but didn't manage to find anything.
>>Could NetBSD add support for the EV_OOBAND flag?
>>Who is responsible for these sorts of things?
>
> I think that only Apple has this; FreeBSD does not seem to. And it does not
> handle priority events, but socket out of band data.
>
> christos

Ah, you're possibly right about it missing on FreeBSD, I got confused :P

On OSX though, poll() with POLLPRI is actually implemented **using**
kqueue with EV_OOBAND.
See: http://fxr.watson.org/fxr/source/bsd/kern/sys_generic.c?v=xnu-1699.24.8#L149