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From: "Anh Vo" <anhvofrcaus@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Not null feature with anonymous and named access types
Date: 13 Jun 2006 08:27:56 -0700
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Date: 2006-06-13T08:27:56-07:00
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Dmitry A. Kazakov wrote:
> On 12 Jun 2006 16:13:34 -0700, Anh Vo wrote:
>
> > Bj=F6rn Persson wrote:
> >> Anh Vo wrote:
> >>> I have been exploring the not null feature with anonymous access type
> >>> and named access type. One thing have learned that an access variable
> >>> declared based on these types will raise a Constraint_Error when
> >>> deallocating this access variable as shown in the code below.
> >>
> >> Of course. Deallocation sets the access variable to null, and that
> >> violates the not-null constraint.
> >>
> > Thanks for your quick reply.
> >
> > Based on this requirement, one should not use not null access in this
> > case due to memory leak as the result of memory deallocation
> > incapability.
>
> Often memory management and handling objects should be well separated. In
> public interfaces, where pointers are needed, null access types can be ve=
ry
> useful. This by no means should prevent the implementation interfaces from
> using plain pointers, arena allocators, garbage collectors, etc to manage
> memory.

Agreed. However, memory leak occurs when the scope is complete in this
case. Therefore, not null access should be used with extreme care.
Otherwise, memory leak is almost certain.

AV