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From: Mats Weber <Mats.Weber@elca-matrix.ch>
Subject: Re: idiom for task termination?
Date: 1997/02/10
Message-ID: <32FF32D7.67D2@elca-matrix.ch>#1/1
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Date: 1997-02-10T00:00:00+00:00
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> package P is
>    procedure Initialize (...);
>    procedure Finalize;
>    ...
> end;

If you modify this abstract state machine to make it an abstract state
type, then you can somewhat alleviate the termination problems:

package P is

   type ADT is limited private;

   procedure Init (X : in out ADT; ...);
   procedure Finalize (X : in out ADT);

   ...

private

   task type ADT is
      entry Init (...);
      entry Stop;
      entry E1;
   end ADT;

end;

The user of P will then delcare an object of type P.ADT, which will make
him the master of the task object, and the terminate alternative in the
body of ADT will be selected when the program terminates.