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From: Stephen Leake <Stephen.Leake@gsfc.nasa.gov>
Subject: Re: Using windows API functions
Date: 1998/07/10
Message-ID: <uk95ll1nj.fsf@gsfc.nasa.gov>#1/1
X-Deja-AN: 370335056
References: <900065152.385075@dedale.pandemonium.fr>
 <6o569h$p78$1@cnn.Princeton.EDU>
Organization: NASA Goddard Space Flight Center -- Greenbelt, Maryland USA
Newsgroups: comp.lang.ada
Date: 1998-07-10T00:00:00+00:00
List-Id: <comp.lang.ada>

mcc@tyrolia.cs.princeton.edu (Martin C. Carlisle) writes:

> In article <900065152.385075@dedale.pandemonium.fr>,
> Antoine JORGE RIBEIRO <softst1@bruker.fr> wrote:
> >hi!
> >I desesperatly try to manage with the function ReadFile from Win32.Winbase,
> >in object ada (Aonix) and I don't understand How to use it and How the
> >lpBuffer : Win32.lpVoid might be used.
> >what's lpVoid, How can I Point to an array of Byte (mod 2**8).
> 
> Win32Ada binds to C, where one can go from (void *) to (char *) at the
> drop of a hat.  In Ada, I'd suggest an Unchecked_Conversion from
> your pointer type to Win32.lpvoid.
> 

Actually, if you read the Win32Ada source code (always a good idea!),
you will find that Win32.lpvoid is just a renaming of System.Address.
Thus to find lpvoid for a buffer:

Data : my_data_type;

use 'address:

ReadFile
(lpBuffer => Data'address,
 ...
);

Have fun!

-- Stephe