[Mingw-users] DLL Linking Woes

[Max B. <ba...@uc...>]

Hi, all.
I have an MSVC-compiled executable. Let's call it super.exe. super.exe
dynamically loads a DLL called ui/uix86.dll from its working directory. It
expects uix86.dll to export two functions: dll_init and main_vm. They are both
exported with __cdecl. I am trying to use MinGW/MSYS to produce such a dll. 

Compiling my code for uix86 into object files is a piece of cake. Linking them
into a usable DLL is not. First of all, here is the .def file I'm using to make
the DLL:

EXPORTS
        main_vm
        dll_init

Quite simple. I have looked here:
http://mywebpage.netscape.com/yongweiwu/stdcall.htm
and here:
http://www.mingw.org/mingwfaq.shtml#faq-msvcdll
After reading these and searching the mailing list archives as well as
sourceforge would let me, I've been trying to produce the DLL using this command:
dllwrap --def ui.def -o pathtosuper/ui/uix86.dll *.o
Problem is, super.exe simply fails to load the resulting DLL. After looking at
that first webpage, I figured that there shouldn't be any problems with exported
function names (_'s and @'s and such) since my two functions are using the
__cdecl calling convention. But I've tried the -k and --add-stdcall-alias
options to dllwrap just in case. No difference as far as super.exe is concerned.

So I used depends.exe (www.dependencywalker.com) to look at my uix86.dll and
compare it to an example DLL that I know works with super.exe. The exported
function names are exactly the same in both, as are their ordinal numbers.
However, I noticed the following differences: Their Hint #'s are swapped, my dll
has subsystem Console rather than GUI, and the example DLL has a link checksum
of zero, whereas my DLL's link checksum is non-zero and equals my Real Checksum.

So are any of these differences enough to explain why it isn't working? If so,
how can I fix that up? If not, what do I need to change in the way I'm
generating my DLL? I tried following that FAQ question I linked to above, but it
doesn't help me at all -- first of all, I don't have the source to super.exe,
and I need to make a DLL it can link to at runtime, NOT a .lib (I assume this is
the windows equiv of .a files?) it can link to at compile time. Basically, I'm a
total noob to making DLLs and Windows programs in general -- I'm really a
unix/linux programmer who has to write something for windows, and would much
rather use a familiar/portable build environment like MinGW rather than shell
out for MSVC.

Thanks for any help, guys (and gals).

--
Max Bane