[fpc-pascal] Parallel Port Access with Free Pascal - windows

[Marc Santhoff]

On Sa, 2016-07-23 at 05:55 +0200, Marc Santhoff wrote:
> On Fr, 2016-07-22 at 18:20 -0400, James Richters wrote:
> > I'm trying to avoid custom hardware if possible.  I have always used
> > parallel ports and never had a problem with them until now.   I like the
> > idea of a parallel port because they are still built onto motherboards, and
> > there are also a TON of USB to parallel port adapters out there.   I'm
> > trying to keep this simple.
> > 
> > I put a repository of my test program here:
> > https://github.com/Zaaphod/FPC-Parallel-Port.  Perhaps someone can see what
> > I'm doing wrong.    I'm reading 255s no matter what I do.    I included my
> > old turbo pascal test program.  I would normally specify the port in hex
> > with a $ like this $378.  I could write to the port then read back what I
> > just wrote.. which is what I am trying to do now.. I don't have anything
> > hooked up to the port yet, I should be able to write to it and read it back.
> > 
> > I seem to be accessing the DLL correctly, because I tried it on a windows 7
> > computer and  IsInpOutDriverOpen was false, because I forgot to install the
> > driver, once I installed the driver IsInpOutDriverOpen is now true, so that
> > tells me I'm accessing the DLL and the DLL is confirming the driver is open.
> 
> >From what I know, although it may be a bit outdated, on windows external
> functions have to be declared 'cdecl'. Which isn't so in the library
> port to pascal.
> 
> One example:
> 
>   implementation
>   Function IsInpOutDriverOpen; external 'inpout32.DLL';
> 
> would then be:
> 
>   implementation
>   Function IsInpOutDriverOpen; cdecl; external 'inpout32.DLL';

No, sorry. It has to be the other way round:

  Function IsInpOutDriverOpen; {$ifndef Win32}cdecl{$else}stdcall{$endif}; external 'inpout32.DLL';

I didn't recognize that it is  $ifndef, not $ifdef.

Marc