gnat3.04a1 on Win95: linking a DLL

gnat3.04a1 on Win95: linking a DLL

[Terry J. Westley]

Newbie on Windows 95 searching for info on how to "link" a GNAT Ada program
with a DLL.  Actually, I want to know how to tell the linker NOT to attempt
to resolve a reference to a symbol I know to be in the DLL.

After searching Lycos, DejaNews, the GCC and GNAT docs, I can not find
anything on this subject.  Lots of stuff on how to create a DLL with GNAT,
but not on how to link with an existing one.  My last idea was that it
was a variation on pragma Interface, but couldn't find anything in
sem_prag.adb.

Any suggestions?

-- 
Terry J. Westley
westley@buffnet.net
http://www.buffnet.net/~westley/

Re: gnat3.04a1 on Win95: linking a DLL

[Tom Griest]

westley@buffnet.net (Terry J. Westley) writes:
>Newbie on Windows 95 searching for info on how to "link" a GNAT Ada program
>with a DLL.  Actually, I want to know how to tell the linker NOT to attempt
>to resolve a reference to a symbol I know to be in the DLL.

The linker must resolve dynamically linked objects to a dll
entry point.  Linking with a DLL is done in an almost transparent way.
You simply link with the existing .lib file.  Now if what you mean
is making a binding to an existing library, then you can
use pragma Import.  Use C as the calling convention unless
the calling convention is STDCALL in which case use stdcall.
Also, note that for DLL data you should use stdcall to insure
indirect references are generated.

-Tom
LabTek Corp.

Re: gnat3.04a1 on Win95: linking a DLL

[Ted Dennison]

Terry J. Westley wrote:
> 
> Newbie on Windows 95 searching for info on how to "link" a GNAT Ada program
> with a DLL.  Actually, I want to know how to tell the linker NOT to attempt
> to resolve a reference to a symbol I know to be in the DLL.
> 
> After searching Lycos, DejaNews, the GCC and GNAT docs, I can not find
> anything on this subject.  Lots of stuff on how to create a DLL with GNAT,
> but not on how to link with an existing one.  My last idea was that it
> was a variation on pragma Interface, but couldn't find anything in
> sem_prag.adb.

I know this story well, as I went through it myself about a month ago. Here
are your options -

  o  Purchase a Microsoft Linker. One comes with Visaul C++ (about $300). 
     Install it, then rebuild LabTek's gnat.

  o  Search the net for a Win32 lib*.a file made from that DLL. The gnu linker
     uses lib*.a files, not *.DLL files. If its a Micro$oft DLL, you are probably
     out of luck.

  o  Create a lib*.a from the DLL. There are detailed instructions on how to
     do this in the GnuWin32 mailing list archives
     ( http://www.cygnus.com/ml/gnu-win32/ ). It is not a simple process, and
     is not even fully automated (unless you have access to a Linux machine).

     If anyone has a better method for making the lib's from DLL's, please 
     speak up!


Out of curiosity, which DLL do you want?
-- 
T.E.D.          
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