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From: "(see below)" <yaldnif.w@blueyonder.co.uk>
Newsgroups: comp.lang.ada
Subject: Re: Bit operations in Ada (endianness)
Date: Mon, 02 Jun 2008 15:01:19 +0100
Message-ID: <C469BBBF.EAE06%yaldnif.w@blueyonder.co.uk>
References: <g17cct$cup$1@aioe.org> <87wslksmgk.fsf@ludovic-brenta.org>
 <m2r6brzpci.fsf@mac.com> <g20sg4$nkb$1@aioe.org>
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Date: 2008-06-02T15:01:19+01:00
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On 02/06/2008 14:27, in article g20sg4$nkb$1@aioe.org, "Dennis Hoppe"
<dennis.hoppe@hoppinet.de> wrote:
 
> I also wonder, if I can query the operating system via Ada,
> which endianness it uses.

No need to talk to the OS.
Try something like this:

   -- N.B. not tested as written!

   not_little_endian : exception;

   type i08 is mod 2**8;
   type i64 is mod 2**64;

   type i08_group is array (0..7) of i08;
   for  i08_group'Component_Size use 8;
   for  i08_group'Size use 64;

   the_i64       : i64 := 0;
   the_i08_group : i08_group;
   for the_i08_group'Address use the_i64'Address;
   pragma Import (Ada, the_i08_group);
   --
   the_i08_group(0) := 1;
   if the_i64 /= 1 then
      raise not_little_endian
   end if;
-- 
Bill Findlay
<surname><forename> chez blueyonder.co.uk