Re: Finalization of static package variables

[Manuel Collado <m.collado@lml.ls.fi.upm.es>]

Stephen Leake escribi�:
> Manuel Collado <m.collado@lml.ls.fi.upm.es> writes:
>> Stephen Leake escribi�:
>>> Manuel Collado <m.collado@lml.ls.fi.upm.es> writes:
>>> ...
>>>> But this is probably not standard-conformant (ARM 13.11.2-16).
>>> This paragraph says:
>>>     Evaluating a name that denotes a nonexistent object is erroneous.
>>>     The execution of a call to an instance of Unchecked_Deallocation
>>>     is erroneous if the object was created other than by an allocator
>>>     for an access type whose pool is Name'Storage_Pool.
>>> I don't see how that is relevant to your problem.
>> "... erroneous ... if the object was created other than by an
>> allocator for an access type whose pool is Name'Storage_Pool."
>>
>> Are static package variables allocated in this pool?
> 
> static package variables are created in the heap.
> 
> If they are _pointers_, the objects that they point to are allocated in
> some pool.
> 
> There is a big difference between a pointer variable, and the object
> it points to.

That's what I've teached to my students for decades :-)

But an access variable can refer to a static variable. Is the following 
Ada95 code schema legal? What about Ada200x (or just Ada, if you want)? 
It seems to work in GNAT-3.15p (it lets finalize 'Edit'), but ...

-------------------------------------------------
package body View_Editor is

    Edit: aliased Dialog_Type :=
       Dialog (420, 350, "Conversion Rates", 'Q', Main_Font);

[...snipped...]

    procedure Editor_Destroy is
       type Dialog_Access is access all Dialog_Type;
       procedure Dispose is
          new Ada.Unchecked_Deallocation (
          Object => Dialog_Type,
          Name   => Dialog_Access );
       Pointer: Dialog_Access := Edit'access;
    begin
       Dispose (Pointer);
    end Editor_Destroy;

end View_Editor;
--------------------------------------------------

Thanks.
-- 
Manuel Collado - http://lml.ls.fi.upm.es/~mcollado