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References: <E18jGE0-0003dI-00@porton.narod.ru> <uptpwoz8r.fsf@nasa.gov>
From: porton@ex-code.com (Victor Porton)
Subject: Re: Pitfall: freeing access discriminants
Newsgroups: comp.lang.ada
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Date: Fri, 14 Feb 2003 00:24:41 +0500
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In article <uptpwoz8r.fsf@nasa.gov>,
	Stephen Leake <Stephen.A.Leake@nasa.gov> writes:
> porton@ex-code.com (Victor Porton) writes:
> 
>> type Integer_Access is access Integer;
>> 
>> type T(D: access Integer) is Ada.Limited_Controlled with null record;
>> 
>> procedure Finalize(Object: in out T) is
>>   -- Error: cannot convert access discriminant to non-local access type
>>   D: Integer_Access := Integer_Access(Object.D);
>> begin
>>   Free(D);
>> end;
>> 
>> What to do? It seems being a serious deficiency in Ada or there are a 
>> workaround?
> 
> Why would you ever want to free an access discriminant? I usually use
> them to point to a constant object.
> 
> One good rule for dynamic memory allocation; never free something you
> did not allocate.

Just

X: T(new Integer'(12)); -- The real example is more natural
  -- than allocating an integer.

However I realized that Ada access discriminants are not to be used in 
such the way as this causes a great non-reliability. I switched to 
just record memebers of an access type.