Re: Low_Level_IO, what is it?

["Randy Brukardt" <randy@rrsoftware.com>]

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"Yannick Duch�ne (Hibou57)" <yannick_duchene@yahoo.fr> wrote in message 
news:op.wfc5jfaaule2fv@douda-yannick...
>Le Sun, 03 Jun 2012 17:59:59 +0200, Dennis Lee Bieber 
><wlfraed@ix.netcom.com> a �crit:
>
>> On Sun, 3 Jun 2012 08:04:05 -0700 (PDT), heresy-me@hotmail.com declaimed
>> the following in comp.lang.ada:
>>
>>> Low_Level_IO, a Ada package name that I saw in some older Ada book.But
>>> I cannot found it in Ada12 Reference.
>>> What is Low_Level_IO?
>>
>> Most likely a description of an "idealized" interface to machine
>> specific I/O operations, intended for use in an pure Ada run-time --
>> instead of the more common POSIX/C run-time bindings (as used by GNAT)
>> on top of a full OS.
>>
>> Ah, yes... Ada 83
>> http://archive.adaic.com/docs/style-guide/83style/html/sty-07-07.html#7.7.4
>
>
>A further link gives its incomplete definition:
>
>    package LOW_LEVEL_IO is
>       --  declarations of the possible types for DEVICE and DATA;
>       --  declarations of overloaded procedures for these types:
>       procedure SEND_CONTROL    (DEVICE : device_type; DATA : in out 
> data_type);
>       procedure RECEIVE_CONTROL (DEVICE : device_type; DATA : in out 
> data_type);
>    end;
>
>Also, the casing is funny.

Haw, nothing funny about this; that's the "standard" way of writing Ada 83 
code. Large amounts of original Ada 83 code was written in this style. It 
was so ugly that the "standard" casing was changed in Ada 95. (Before that, 
most of us invented our own styles, so it was a real mess to integrate 
someone else's code.)

As far a Low_Level_IO itself, the package was always optional in Ada 83, and 
there was hardly anyone who ever implemented it (we had packages of our own 
design for this purpose, they were much closer to the Intel instruction 
set). So it was removed from Ada 95.

                                      Randy.