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Message-ID: <3BBA6027.DF416C76@ece.gatech.edu>
Date: Tue, 02 Oct 2001 20:47:35 -0400
From: Charles Wilson <cwilson AT ece DOT gatech DOT edu>
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To: "Asbenson, Lyndell L" <lyndell DOT l DOT asbenson AT intel DOT com>
CC: "'cygwin AT cygwin DOT com'" <cygwin AT cygwin DOT com>
Subject: Re: DLL Win 2000
References: <31A90D7E3560D511AC7400A0C96B2730012BF2BC AT fmsmsx59 DOT fm DOT intel DOT com>
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I think you should use the Microsoft tools to turn gpib_lang_ms.obj into
a dll (no, I dunno how to do that; it may not even be possible).  Then
use dlltool (again) to create a gcc-compatible import lib for that new
dll.  finally, link your app against both dlls.

The problem is, MS .obj format files are NOT compatible with gcc/ld. 
I'm really surprised you were able to link at all.

Another solution is to search the net for a tool that can convert .obj
files into .o files.  I do not know if such a tool exists.

However, since this topic has really degenerated into a "using
mingw/cygwin-gcc-mno-cygwin with MSVC" interoperability discussion, it
really doesn't belong on the cygwin mailing list anymore.  *Perhaps* the
mingw list would be a better choice -- but the gpib card vendor's
support mailing list would be the best option.

--Chuck

"Asbenson, Lyndell L" wrote:
> 
> Chuck,
> We are just about there, one more question. I have
> a gpib-32.dll which now works properly I also have
> a Microsoft C++ gpib_lang_ms.obj file which is a language
> interface file. In using the -mno-cygwin I don't get any
> errors but when I compile the program and run the .exe
> it runs into memory violations. Is there another way of
> using or compiling in language.obj object files?
> Thanks,
> Lyndell Lee Asbenson
> 
> -----Original Message-----
> From: Charles Wilson [mailto:cwilson AT ece DOT gatech DOT edu]
> Sent: Saturday, September 29, 2001 2:52 PM
> To: Asbenson, Lyndell L
> Cc: 'cygwin AT cygwin DOT com'
> Subject: Re: DLL Win 2000
> 
> Asbenson, Lyndell L wrote:
> 
> > I have national instruments drivers for a GPIB device and all that they
> > offer
> > is DLLs and Language interfaces for Borland C++ or Microsoft C++. I have
> > also
> > look at your DLL conversion process 5 steeps. Is there any tool that will
> > convert a DLL 32 bit to a static library where I could use this in the
> > Cygwin
> > environment?
> 
> Sort of.  You can create an gcc-style import library for the DLL (search
> for help/docu on 'dlltool' for more information).  This import lib will
> work with both cygwin's gcc and with mingw's gcc.
> 
> However, the odds are that any code you write must be compiled with the
> 'gcc -mno-cygwin' option of cygwin's compiler, or you should just use
> the mingw compiler.  The reason for this is that the NI DLL *probably*
> was built to depend on msvcrt.dll, not cygwin1.dll.  Since both of these
> provide runtime services - and you can only have one runtime lib for a
> given app - your app will also have to be linked against msvcrt.dll (not
> cygwin1.dll)  Ergo, -mno-cygwin (or just use mingw comiler, not cygwin
> compiler).  You can check the dependencies of your NI DLL thus:
>   cygcheck my_ni_dll.dll
> 
> --Chuck

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