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Date: Mon, 18 Nov 2002 18:04:39 -0800 (PST)
From: Davide Libenzi <davidel@xmailserver.org>
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To: Dan Kegel <dank@kegel.com>
cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [rfc] epoll interface change and glibc bits ...
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On Mon, 18 Nov 2002, Dan Kegel wrote:

> Davide Libenzi wrote:
> > On Mon, 18 Nov 2002, Dan Kegel wrote:
> >>Second, epoll_ctl(2) doesn't define the meaning of the
> >>event mask.  It should give the allowed bits and define
> >>their meanings.  If we use the traditional POLLIN etc, we
> >>can say
> >>   POLLIN - the fd has become ready for reading
> >>   POLLOUT - the fd has become ready for writing
> >>   Note: If epoll tells you e.g. POLLIN, it means that
> >>            poll will tell you the same thing,
> >>            since poll gives the current status,
> >>            and epoll gives changes in status.
> >
> >
> > I will have to change man pages also to fit EPOLL* definitions.
>
> IMHO changing from using POLLIN etc. to EPOLLIN
> will obscure the essential relationship between
> epoll and poll (namely, that the epoll bits
> are the time derivative of the poll bits).
>
> I would prefer to continue using POLLIN, etc.

Dan, at the beginning I had the same thought as yours. Now I sort of
changed my mind. The epoll interface is basically seeing the light in
these days and even if right now it uses f_op->poll(), tomorrow we don't
know. To avoid painful code changes later is IMHO better to define EPOLL*
bits right now. They'll be the same of the POLL* bits but will enable
epoll to be independent from poll.h bits. At least to the outside world.
Same for the event structure.



- Davide


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