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From: simon.j.wright@gecm.com (Simon Wright)
Subject: Deallocation via class-wide pointer
Date: 1996/11/22
Message-ID: <x7vralm3vqf.fsf@luthien.frlngtn.gmcs.gecm.com>#1/1
X-Deja-AN: 198099692
sender: sjw@luthien.frlngtn.gmcs.gecm.com
organization: Ferranti Naval Systems, GEC-Marconi S3I Combat Systems Division
newsgroups: comp.lang.ada
Date: 1996-11-22T00:00:00+00:00
List-Id: <comp.lang.ada>


I have a type T and a class-wide pointer:

  type T is tagged with null record;
  type TP is access T'Class;

I have a queue of T's (and, of course, types extended from T) to
process. The individual objects are allocated dynamically and put into
some Queue package, which manages TP's.

What I want to do is to pop the objects off the queue, process them
(via some appropriate dispatching operation) and then deallocate the
memory.

For the life of me I can't see how to get to call

  type TPP is access T;
  procedure Free is new Unchecked_Deallocation (T, TPP);

This must be a common problem, I guess I'm just looking at it wrong;
any thoughts?


-- 
Simon Wright                                    (G-net) +842-1778
Ferranti Naval Systems                  (voice) +44(0)1705-701778
GEC-Marconi S3I Combat Systems Division   (fax) +44(0)1705-701800