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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Finalization of library level tasks
Date: Wed, 18 Apr 2018 16:12:30 +0200
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Xref: reader02.eternal-september.org comp.lang.ada:51592
Date: 2018-04-18T16:12:30+02:00
List-Id: <comp.lang.ada>

On 18/04/2018 15:51, J-P. Rosen wrote:
> Le 18/04/2018 à 14:25, Dmitry A. Kazakov a écrit :
>> Sorry, but it does not work at all, because there is no any way to
>> terminate task. If intended task termination has race condition, uses
>> arbitrary dependencies between unrelated tasks, ignores stated
>> dependencies, e.g. between the packages, deadlocks in finalization, then
>> there must be something wrong with the intention.
> It has not, or your termination conditions call for a higher protocol.
> All your suggestions are undecidable; please provide an example of the
> problem.

Problem: A worker task encapsulated into an object. The task does some 
calculations or some I/O in chunks. The task's activity is not induced 
by other tasks. When the object finalizes the task must go with it. 
Nothing more.

In pseudo-code:

    task body Worker is
    begin
       while the object lives loop
          do some chunk of work
       end loop;
    end Worker;

P.S. I posted an example in a separate thread. The posted solution 
should work except the cases when the access type is at the same level 
as the object and both are below the library level.

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de