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From: "Randy Brukardt" <randy@rrsoftware.com>
Newsgroups: comp.lang.ada
Subject: Re: Representation clauses for base-64 encoding
Date: Thu, 22 Dec 2011 19:30:20 -0600
Organization: Jacob Sparre Andersen Research & Innovation
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Date: 2011-12-22T19:30:20-06:00
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"Niklas Holsti" <niklas.holsti@tidorum.invalid> wrote in message 
news:9lgi3jFhaU1@mid.individual.net...
> On 11-12-22 11:41 , Natasha Kerensikova wrote:
...
>>     type Octet_Block is array (1 .. 3) of Octet;
>>     pragma Pack (Octet_Block);
>
> I would add the following, to check that packing is effective:
>
>       for Octet_Block'Size use 24;

I think it would probably be better to forget Pack and actually say what you 
mean here:

    type Octet_Block is array (1 .. 3) of Octet;
    for Octet_Block'Component_Size use 8;

"Pack" should be reserved for cases where you don't care about the exact 
layout, you just want to save space. Here you do care about the exact 
layout, so use a Component_Size.

                                  Randy.