Date: Mon, 16 Jun 2003 23:11:01 -0700 From: Wes Peters <wes@softweyr.com> To: Eric Jacobs <eaja@erols.com>, freebsd-hackers@freebsd.org Subject: Re: kqueue alternative? Message-ID: <200306162311.01163.wes@softweyr.com> In-Reply-To: <20030616143936.71007de2.eaja@erols.com> References: <1079.10.0.81.10.1055692530.squirrel@www.mundomateo.com> <20030616171110.GC56734@webserver.get-linux.org> <20030616143936.71007de2.eaja@erols.com>
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On Monday 16 June 2003 11:39 am, Eric Jacobs wrote:
> On Mon, 16 Jun 2003 10:11:10 -0700
>
> Joshua Oreman <oremanj@www.get-linux.org> wrote:
> > On Mon, Jun 16, 2003 at 11:44:15AM +0100 or thereabouts, Tony Finch
seemed to write:
> > > Select doesn't work with files.
> >
> > Really? `man 2 select' says nothing about that. It just talks about
> > 'file descriptors'. Now if it said 'socket descriptors' or 'non-file
> > file descriptors' I would understand, but I don't think that that
> > statement is implied by the man page. Is there something I'm missing?
>
> A file descriptor that references an ordinary vnode (file or directory)
> will always be "ready for I/O", because unlike a socket or pipe, it
> never needs to block in order to tell you if it's at EOF.
>
> So, while it works, and is logical, it isn't terribly useful.
It's useful from the standpoint that the same select code that works with
a device or socket handle, both of which can block, will work with a file
handle that can't block or a pipe handle that can block. Looked at in
this light, it would be really stupid if select didn't behave as it does
when fed a file handle.
--
Where am I, and what am I doing in this handbasket?
Wes Peters wes@softweyr.com
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