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-7-bit
X-Google-Thread: 103376,7dac35d19d7d0d84
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2003-03-14 09:20:22 PST
Path: 
 archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newsfeed.icl.net!newsfeed.fjserv.net!newsfeed.icl.net!newsfeed.fjserv.net!newsfeed.frii.net!newsfeed.frii.net!news.compaq.com!uunet!sac.uu.net!nntp.TheWorld.com!not-for-mail
From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Getting modular type size in bits
Date: 14 Mar 2003 12:20:20 -0500
Organization: The World Public Access UNIX, Brookline, MA
Message-ID: <wccznnxrhkb.fsf@shell01.TheWorld.com>
References: <MPG.18dc0d98f36ac6bb9896b9@News.CIS.DFN.DE>
 <wccllziymyv.fsf@shell01.TheWorld.com>
 <slrnb73uer.o1.lutz@taranis.iks-jena.de>
NNTP-Posting-Host: shell01.theworld.com
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
X-Trace: pcls4.std.com 1047662420 10262 199.172.62.241 (14 Mar 2003 17:20:20
 GMT)
X-Complaints-To: abuse@TheWorld.com
NNTP-Posting-Date: Fri, 14 Mar 2003 17:20:20 +0000 (UTC)
User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2
Xref: archiver1.google.com comp.lang.ada:35327
Date: 2003-03-14T12:20:20-05:00
List-Id: <comp.lang.ada>

Lutz Donnerhacke <lutz@iks-jena.de> writes:

> * Robert A Duff wrote:
> > Jano <402450@cepsz.unizar.es> writes:
> >> I want to know that the type size is 5. I'm aware of the 'modulus 
> >> attribute, and 'size. If I understand correctly, 'size returns the size 
> >> allocated by the compiler for the type (normally 8 in this case), not 
> >> the _minimum_ size to allocate it (which is what I would need in that 
> >> case).
> >
> > 'Size returns the minimum -- i.e. how big it would be if it were a
> > component of a packed record.  That's 32 in this case.  If it were
> > "mod 2**5", then Number'Size would be 5, not 8.
> 
> $ cat t.adb
> with Ada.Text_IO;
> 
> procedure t is
>    type A is mod 2**5;
>    for A'Size use 8;
> begin
>    Ada.Text_IO.Put_Line(Natural'Image(A'Size));
>    declare
>       type B is new A;
>    begin
>       Ada.Text_IO.Put_Line(Natural'Image(B'Size));
>    end;
> end t;
> $ ./t
>  8
>  8
> $ _

So?  You asked for 8, and you got 8.  And it will be (at least) 8 bits
in a packed record.  If you take out the "for A'Size ...", which was not
in the original poster's example, it should be 5.

- Bob