Access to an I/O port address is not a function of the compiler ... it is
the O/S that controls this.  If you are using Windows NT, your app can not
directly perform I/O to an I/O address ... you have to go through a kernel
mode driver.

Win9x does not have the same hardware abstraction layer, and therefore does
not have the same limitation.

Mitch Miller, Omaha, NE
mdmiller2@home.com

----- Original Message -----
From: "Herbert Graf" <hgraf@BETTER.NET>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Monday, February 07, 2000 2:43 PM
Subject: [OT]RE: Parallel Port access via C.


> > I am using the Borland C 5.0 compiler, so with bcc prog.c, I could get
the
> > prog.exe file that really worked well.
> >
> > The problem is that I want to work with the 32 bit compiler type and
with
> > bcc32 prog.c, instead of the prog.exe file I just got an error message
> > saying that the outportb function was not prototyped and that
> > function could
> > not be resolved. The same kind of mistake can happen when you forget to
> > include a .h file with the prototype of a function you are using (for
> > instance, use of printf without including stdio.h), but this is not the
> > case. How can I handle this situation?
>
>         I believe the problem is that you are using the 32bit compiler! :)
Once you
> enter the wonderful world of 32 bit on a PC you also enter the world of
> protection, the system doesn't allow direct access to hardware by a user
> level program. This is akin to why NT doesn't allow most if not all DOS
> games with sound support work properly, the programs are trying to access
> the hardware directly. This is actually good, it is really the only way to
> make a stable system. I recommend that unless you have a good reason,
stick
> with the 16 bit compiler. If you need to access hardware in 32 bit mode
you
> will have to either create a driver or access a driver already installed.
> TTYL
>