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From: Jeffrey Carter <spam.jrcarter.not@spam.not.acm.org>
Newsgroups: comp.lang.ada
Subject: Re: Task with access to itself?
Date: Wed, 05 Dec 2012 09:57:00 -0700
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Date: 2012-12-05T09:57:00-07:00
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On 12/05/2012 06:53 AM, Jacob Sparre Andersen wrote:
> I would like to maintain a collection of tasks, where the tasks
> themselves can register their availability.
>
> My immediate thought was to let the tasks know their own address
> ('Access), such that they can simply pass that to the collection of
> available tasks, when they are ready.  But I haven't found a nice way to
> implement that pattern, so may be I should do it a different way.

We make extensive use of a similar pattern, but rather than having the tasks 
register their availability and be given work to do, we have the tasks get their 
work from a protected queue. The task body tends to look like

Forever : loop
    exit Forever when Finalization.Control.Finalizing; -- Protected function

    select
       Work_Queue.Get (Item => Work_Item);
       -- Blocks until something is on the queue
       Process (Job_Info => Work_Item);
    or
       delay ...;
    end select;
end loop Forever;

-- 
Jeff Carter
"If I could find a sheriff who so offends the citizens of Rock
Ridge that his very appearance would drive them out of town ...
but where would I find such a man? Why am I asking you?"
Blazing Saddles
37