From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII
X-Google-Thread: 103376,f196003f7b36852b,start
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2001-04-24 03:19:41 PST
Path: 
 newsfeed.google.com!newsfeed.stanford.edu!news.tele.dk!195.158.233.21!news1.ebone.net!news.ebone.net!newsfeeds.net.uni-c.dk!uninett.no!ntnu.no!randhol+abuse
From: randhol+abuse@pvv.org (Preben Randhol)
Newsgroups: comp.lang.ada
Subject: Question about Finalization Control and reference counting
Date: Sat, 21 Apr 2001 12:37:26 +0000 (UTC)
Organization: Norwegian university of science and technology
Message-ID: <slrn9e2vqb.aah.randhol+abuse@kiuk0156.chembio.ntnu.no>
NNTP-Posting-Host: kiuk0156.chembio.ntnu.no
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
X-Trace: tyfon.itea.ntnu.no 987856646 25477 129.241.83.82 (21 Apr 2001
 12:37:26 GMT)
X-Complaints-To: usenet@itea.ntnu.no
NNTP-Posting-Date: Sat, 21 Apr 2001 12:37:26 +0000 (UTC)
User-Agent: slrn/0.9.6.3 (Linux)
Xref: newsfeed.google.com comp.lang.ada:6882
Date: 2001-04-21T12:37:26+00:00
List-Id: <comp.lang.ada>


Hi

I'm wondering if it is possible to do something like this

   type Data_Type is new Ada.Finalization.Controlled with
      record
         References: Integer := 0;
   end record;
   
   type Data_Access_Type is access Data_Type;

[..]

and then in the main program if I do something like this:

   procedure main is

      Pointer : Data_Access_Type := null;
      Data : Data_Access_Type := new Data_Type;
   
   begin
   
      Pointer := Data; 

   end main;

to have Data.References increases by using Adjust? I'm trying but it
looks like it only works if I do:

   Pointer : Data_Type;
   ...
   Pointer := Data.all;
   ...
otherwise Adjust is not invoked. Is it possible to get it invoked if one
point an access type to an object? I'm trying to eliminate the problem
of dangling pointers in a program...

Thanks in advance.

-- 
Preben Randhol ------------------- http://www.pvv.org/~randhol/ --
                 �For me, Ada95 puts back the joy in programming.�