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=-1.3 required=5.0 tests=BAYES_00,INVALID_MSGID
	autolearn=no autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,fd398ca223dbbfd6
X-Google-Attributes: gid103376,public
From: lutz@iks-jena.de (Lutz Donnerhacke)
Subject: Re: 'Size (novice question)
Date: 2000/02/22
Message-ID: <slrn8b50op.ig.lutz@taranis.iks-jena.de>#1/1
X-Deja-AN: 588369372
Distribution: world
Content-Transfer-Encoding: 8bit
References: <38ACA68D.CEA7E03F@interact.net.au>
 <wccsnyqof2a.fsf@world.std.com> <slrn8aqgfn.15u.lutz@taranis.iks-jena.de>
 <87aekxlz33.fsf@deneb.cygnus.argh.org>
Content-Type: text/plain; charset=ISO-8859-1
Organization: IKS GmbH Jena
Mime-Version: 1.0
User-Agent: slrn/0.9.5.7 (UNIX)
Newsgroups: comp.lang.ada
Date: 2000-02-22T00:00:00+00:00
List-Id: <comp.lang.ada>

* Florian Weimer wrote:
>   Put ("Boolean'Size (type):     "); Put (Boolean'Size); New_Line;
>   Put ("Boolean'Size (variable): "); Put (X'Size); New_Line;
>
>Almost no compiler will print 1 twice because on most architectures,
>access to individual bits is expensive in both time and space when
>compared to word or even octet access.

But the following code can not use compressed variables:

with Ada.Text_IO, Ada.Integer_Text_IO;
use Ada.Text_IO, Ada.Integer_Text_IO;
procedure Size_Difference is
   X1, X2 : Boolean;
   A1, A2 : array (1..8) of Boolean;
   pragma Pack (X2,A2);  -- I know, that a named array subtype is packable.
begin
   Put ("Boolean'Size (type): "); Put (Boolean'Size); New_Line;
   Put ("Boolean'Size (X1):   "); Put (X1'Size); New_Line;
   Put ("Boolean'Size (X2):   "); Put (X2'Size); New_Line;
   Put ("Boolean'Size (A1):   "); Put (A1'Size); New_Line;
   Put ("Boolean'Size (A2):   "); Put (A2'Size); New_Line;
end;