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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Finalization of library level tasks
Date: Sun, 15 Apr 2018 19:40:33 +0200
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Xref: reader02.eternal-september.org comp.lang.ada:51525
Date: 2018-04-15T19:40:33+02:00
List-Id: <comp.lang.ada>

On 2018-04-15 19:17, AdaMagica wrote:
> task body Worker_Type is
>    begin
>      loop
>        select
>          accept Quit;
>          exit;
>        or
>          terminate;
>        end select;
>      end loop;
>    end Worker_Type;
> 
>    procedure Finalize (X: in out T) is
>    begin
>      if X.Worker'Callable then
>        X.Worker.Quit;
>      end if;
>    end Finalize;

This task will hang in the select statement.

Terminate alternative is almost always useless because it cannot be 
mixed with "else" or "delay". If there were a way to check within the 
task if its completion has been requested your solution would work. 
Terminate should have been a normal predefined entry:

    task body T is
    begin
       select
          accept T'Terminate;
          exit;
       or ...

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