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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 16:12:57 +0200
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Xref: reader02.eternal-september.org comp.lang.ada:51517
Date: 2018-04-15T16:12:57+02:00
List-Id: <comp.lang.ada>

On 2018-04-15 16:02, Jeffrey R. Carter wrote:
> On 04/15/2018 03:40 PM, Dmitry A. Kazakov wrote:
>>
>> When an instance of T is declared in a library level package, then 
>> Finalize is never called, I guess because the task must terminate 
>> first due to some rules about its masters.
> 
> The rule is that finalization occurs after all dependent tasks have 
> terminated, presumably so a task cannot access a finalized object.

There is only environment task.

>> Is there a way to work this around?
> 
> That depends on the problem, but usually a design can be reworked to 
> provide for termination of tasks.

The problem is that Finalize is called when the object is declared in a 
nested scope:

   procedure Main is
      Data : X;
   begin
      Data.Worker := new Worker_Type;
   end Main; -- Finalize is called (and terminates the task)

This does not work:

   package Library_Level is
      Data : X;
   end Library_Level;

   with Library_Level;
   procedure Main is
   begin
      Library_Level.Data.Worker := new Worker_Type;
   end Main; -- Finalize is not called (presumably waiting for the task)

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