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Date:      01 Jul 2001 01:27:19 +0200
From:      Dag-Erling Smorgrav <des@ofug.org>
To:        "Jonathan Graehl" <jonathan@graehl.org>
Cc:        <arch@freebsd.org>, <jlemon@freebsd.org>
Subject:   Re: New kqueue filter
Message-ID:  <xzp1yo1v99k.fsf@flood.ping.uio.no>
In-Reply-To: <000301c101a3$62b04220$6dfeac40@straylight.com>
References:  <000301c101a3$62b04220$6dfeac40@straylight.com>

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"Jonathan Graehl" <jonathan@graehl.org> writes:
> Jonathan Lemon can speak to this better than I, but I believe this is
> because kevents are supposed to be level and not edge-sensitive (that
> is, "there is data waiting", not "data became available").  The filter
> would run the first time to place the event in the kqueue tentatively,
> and then (some time later, when some other process could have removed
> the event) when the user retrieves events with kevent, the filters run
> again to verify that the condition still exists.

No, the filter function isn't called at all until I actually type
something on the tty, then it runs (and succeeds) twice in a row
before the userland kqueue() call returns.

DES
-- 
Dag-Erling Smorgrav - des@ofug.org

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