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From: "Matthew Heaney" <matthew_heaney@acm.org>
Subject: Re: Deallocating an object referenced via a classwide access type.
Date: 2000/01/11
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References: <slrn87l2rt.15e.aidan@skinner.demon.co.uk>
 <387aa062_4@news1.prserv.net>
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In article <387aa062_4@news1.prserv.net> , "Matthew Heaney" 
<matthew_heaney@acm.org> wrote:

> The basic idea is to declare a private operation (similar to what you
> have in your example) that does the actual deallocation of the specific
> type, and to call this operation by dispatching on the tag of the object
> whose type is class-wide.  Like this:
>
> package P is
>
>   type T (<>) is abstract tagged limited null record;  --0
>
>   type TA is access all T'Class;
>   for TA'Storage_Size use 0;  -- avoid RTS baggage
>
>   <primitive ops for types in T'Class>

Oops!  I forgot to mention that primitive ops for T take access
parameters.  Like this:

  procedure Op (O : access T);

This is so, in order to avoid having to explicitly dereference the
access object returned by constructors.


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