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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: AI12-0218: What is the portable representation clause for
 processing IETF packets on little-endian machines?
Date: Fri, 11 May 2018 17:48:43 +0100
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Date: 2018-05-11T17:48:43+01:00
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"Jeffrey R. Carter" <spam.jrcarter.not@spam.not.acm.org> writes:

> On 05/11/2018 03:49 PM, Simon Wright wrote:
>> Lucretia <laguest9000@googlemail.com> writes:
>>
>>> On Friday, 11 May 2018 08:55:28 UTC+1, Simon Wright  wrote:
>>>> In the body,
>>>>
>>>>     Big_Endian : constant Boolean
>>>>       := System."=" (System.Default_Bit_Order, System.High_Order_First);
>>>>
>>>
>>> Is it not possible to use derived types with different rep clauses to
>>> implement byte swapping on assignment, like the pack/unpack trick can?
>>
>> Maybe nowadays; not when that code was written.
>
> You can, and have been able to since Ada 83.

I must be missing something.

   type T is record
      J : Integer;
   end T;

   type BE_T is new T;
   for BE_T use record
      ?????
   end record;