From: Tucker Taft <stt@averstar.com>
To: davidb42@my-deja.com
Subject: Re: Are delay statements abortable?
Date: 2000/01/10
Date: 2000-01-10T00:00:00+00:00 [thread overview]
Message-ID: <387A3981.A2601F48@averstar.com> (raw)
In-Reply-To: 85buah$hn4$1@nnrp1.deja.com
davidb42@my-deja.com wrote:
>
> Are delay statements interruptable/abortable?
Yes.
>
> I was expecting delay statements in tasks (or in the abortable part of
> an asynchronous select construct) to be brought to a premature end on
> aborting the task (or on the triggering event).
They should be.
>
> However, in the Ada implementation I am using, the abortion only seems
> to take effect at the expiry of the delay.
This would not qualify as a "real-time-systems-annex" supporting
implementation in Ada 95. "Real-time" implementations are required
to abort preemptively in Ada 95 (see RM95 D.6(2)).
>
> For example, in the program below, the main task completes after 25
> seconds, but the dependent task (and thus the program as a whole)
> doesn't terminate until 40 seconds (at expiry of the 2nd 20 second
> delay).
>
> Is this right?
In a non-real-time implementation, this is "correct" but not particularly
helpful. In a "real-time" Ada 95 implementation, this would be incorrect.
> David Bowerman
> CSC Australia.
--
-Tucker Taft stt@averstar.com http://www.averstar.com/~stt/
Technical Director, Distributed IT Solutions (www.averstar.com/tools)
AverStar (formerly Intermetrics, Inc.) Burlington, MA USA
next prev parent reply other threads:[~2000-01-10 0:00 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2000-01-10 0:00 Are delay statements abortable? davidb42
2000-01-10 0:00 ` Ross
2000-01-10 0:00 ` Tucker Taft [this message]
2000-01-10 0:00 ` susan satnford
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