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:
> 
>> Variables declared in the global scope of a package body seem not to
>> be finalized automatically at the end of the whole program (using GNAT
>> 3.15p on WindowsXP).
> [...]
>> After several trial-and-error attemps, an Unchecked_Deallocation on
>> these variables seems to do the trick (the whole program terminates
>> smoothly). 
> 
> Unchecked_Deallocation is used on access variables (aka "pointers").
> Such variables are _not_ automatically finalized by Ada; calling
> Unchecked_Deallocation is the standard-compliant way to finalize them.
> 
>> 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?

> 
> What version of the ARM are you quoting? When you say "ARM" without a
> year, it implies "current" which means "Ada 2007" (or, informally,
> "Ada 2005").

Doesn't "using GNAT 3.15p" give you any hint :-) ?

> [...]
> Posting code that outlines what you are doing would help a lot.

------------------------------------
package body Pkg_Dialog is
    My_Dialog: aliased Dialog_Type := Dialog (200, 100, "Dialog 3", 'Q');
    ...

    procedure Do_Dialog is
    begin
       ... exercise My_Dialog ...

       declare
          type Dialog_Access is access all Dialog_Type;
          procedure Dispose is
             new Ada.Unchecked_Deallocation (
             Object => Dialog_Type,
             Name   => Dialog_Access );
          Pointer: Dialog_Access := My_Dialog'access;
       begin
          Dispose (Pointer);  -- force My_Dialog finalization
       end;
    end Do_Dialog;

end Pkg_Dialog;
-----------------------------------

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