Re: adasockets and adatypes

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

Also, just because you can get there by rolling-your-own operations, in my
mind isn't the same as saying 'Input and 'Output produce "portable" results.
If I've got to go to the extreme of first thoroughly defining the
representation of all the data types involved and second defining 'Input and
'Output for everything involved, then I might just as well have done a
little bit-twiddling with Unchecked_Conversion, etc., and produced my own
message catalog. You already have the rep clauses you need (maybe even fewer
of them!) and one Unchecked_Conversion or overlay later and you're there.

And I still think you've got issues that don't let you absolutely guarantee
representation - at least not if the requirement is that you must be able to
interface to any arbitrary reader/writer at the other end of the stream. You
certainly have little to no control over the language defined types and,
IIRC, there were issues if you needed to span boundaries or otherwise deal
with a stream that might be produced anywhere by anything.

If you have a sufficiently bounded problem, you can probably get there -
albeit with more effort than I'd like to expend. For some specific set of
messages and some specific set of machines/compilers, you can come up with a
consistent production/consumption of the data. But I think you have a hard
time dealing with the more general cases.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com
Web:      http://www.mcondic.com/


"Ted Dennison" <dennison@telepath.com> wrote in message
news:1v6l7.3307$4z.6132@www.newsranger.com...
> In article <mailman.999615244.13142.comp.lang.ada@ada.eu.org>, David C.
Hoos
> says...
> >This is simply not so. If the record component types have user-defined
> >endianness-independent stream attributes, then the data will have the
>
> How does one do this for language-defined types? Every Ada compiler I've
tried
> it on (including gnat 3.13p just now) only allows one to redefine the IO
> attributes in the same declaration section in which the type is declared.
>
> If you only have 2 implementations to get talking, it is fairly easy to
massage
> one end until it talks like the other. That isn't the same thing as true
> portability.
>