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From: Victor Porton <porton@narod.ru>
Newsgroups: comp.lang.ada
Subject: Limited object by reference or access argument?
Date: Mon, 07 Aug 2017 00:16:34 +0300
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Xref: news.eternal-september.org comp.lang.ada:47624
Date: 2017-08-07T00:16:34+03:00
List-Id: <comp.lang.ada>

Suppose we have

type World_Type is tagged limited private;

type BNode_ID_Handler is abstract tagged limited private;

We need to set a bnode handler for a world object. Should the procedure 
signature be

procedure Set_Handler (World: World_Type;
                       Handler: access BNode_ID_Handler'Class);

or 

procedure Set_Handler (World: World_Type;
                       Handler: BNode_ID_Handler'Class);

The later can work with limited BNode_ID_Handler type, because tagged and 
limited types are always passed by reference.

I prefer the second one, because with the first procedure signature it is 
possible to pass an access to an already finalized object what is an error, 
but want to ask you opinion which of the two procedure signatures is better.

-- 
Victor Porton - http://portonvictor.org