Re: Issue with GNAT GPL 2009 and GtkAda

["Alex R. Mosteo" <alejandro@mosteo.com>]

Randy Brukardt wrote:

> "Alex R. Mosteo" <alejandro@mosteo.com> wrote in message
> news:7ajfrgF1vdsnlU1@mid.individual.net...
> ...
>>> declare
>>>    Ptr : access T := new T;
>>> begin
>>>    ...
>>>    External_Ptr := Ptr.all'Uchecked_Access; -- Copy the pointer
>>>    ...
>>> end;  -- Now External_Ptr is dangling, because the object is freed.
>>
>> If I understand correctly, this is because the type of Ptr goes out of
>> scope?
>>
>> I strongly suspect that Gnat does not behave this way, but I should test
>> it.
> 
> Gnat would be wrong if it does *not* behave this way. (Janus/Ada has this
> bug currently.) The master of the anonymous access type is the declare
> block, and it has to be finalized at the end of the scope. I suppose you
> could leave the memory around, but the object has to be finalized (as
> Dmitry's example shows).

No, indeed GNAT GPL 2009 at least is correct. It was my fault; I was almost 
sure of having been doing this in such a way that would have caused dangling 
pointers and immediate crashes. Since this didn't happen, I thought it was 
the compiler's fault. In reality, my remembrance was wrong and in practice 
it was a declaration at the library level so it couldn't happen.

Not nice though, I was completely unaware and that makes me uneasy.