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From: Mario Amado Alves <maa@di.fct.unl.pt>
Subject: Re: Pointer function parameter
Date: 2000/10/19
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Date: 2000-10-19T10:43:11+00:00

On Wed, 18 Oct 2000, Robert Dewar wrote:

> In article
> <Pine.LNX.4.10.10010171217210.17222-100000@lexis.di.fct.unl.pt>,
>   comp.lang.ada@ada.eu.org wrote:
> > Ada access types serve most pointer necessities. In this vein,
> the
> > Ada expression X'Access is the equivalent of the C expression
> &X (X being
> > an object).
> 
> 
> Misleading, since &x is a somewhat fundamental C diction,
> whereas X'Access is rather specialized, and has few legitimate
> uses outside certain well defined areas (including for example
> interfacing to C functions :-)

The "in this vein" is there for a reason: in the vein of using Ada access
types for the same purposes you use C pointer types for--and only in this
vein--, attribute Access is in fact the Ada equivalent of the C address
operator &.

The equivalent strito senso--not in the vein above--is of course attribute
Address. But if you use Address everywhere where you use & in the
equivalent C program, you miss a great part of the gain of using Ada
instead of C.

(Perhaps you read "Address" where it says "Access" in my first reply?)

And surely there is a _lot_ of uses of access types besides interfacing to
C: virtually all dynamic data structures (linked lists, trees, etc.)
require them.

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