Maya Libs Compatible With Mingw?

[mathartspd]

Hello, List!

I have worked out a Makefile which will compile a Maya API SimpleCommand under MinGW/MSys http://www.mingw.org ("Minimalist GNU for Windows")
... up to the point of linking with Maya's API libraries. What you find, when doing this, is that MinGW builds its C++-munged symbol names differently than MSVisualC++ does. (Of course.) In Maya header files, c:/Program Files/Autodesk/Maya8.5/include/maya/MTypes.h:#define PLUGIN_EXPORT _declspec( dllexport )
You might have wondered what that *_EXPORT macro is all about. If you go into c/Program Files/Autodesk/Maya8.5/lib
and do nm -a OpenMaya.lib, you will find things like:
00000000 T ??0MFnPlugin@@AAE@ABVMObject@@PBD11PAVMStatus@@@Z
00000000 I __imp_??0MFnPlugin@@AAE@ABVMObject@@PBD11PAVMStatus@@@Z
-- Two versions of every symbol -- one with _imp_ in front of it and one without. (Why? It's a Window$-ism -- to thwart
reverse-engineering of object code and software bootlegging.) The _declspec( ... ) wrapper is supposed to give us access to the Maya API function calls through the ABI. With MinGW's g++, what I get is:
undefined reference to `_imp___ZN9MFnPluginC1ER7MObjectPKcS3_S3_P7MStatus' -- _declspec( ...) doesn't work the same in MinGW's g++ as it does in M$VisualC++. _declspec( ...) in MinGW's g++ gives you yet another munging of MFnPlugin(MObject, MStatus); which the link loader obviously cannot find in OpenMaya.lib, because it doesn't exist.

I have heard tell of a Perl script which can edit a library file and change the symbol names to something readable by MinGW. Has anyone on the list applied this sort of technique to the Maya API libraries? If not, I am about to dive into it and, if successful, I will post my results to the list. Thanks, --Stewart http://us.imdb.com/Name?Stewart+Dickson
http://www.isl.uiuc.edu/~sdickson http://emsh.calarts.edu/~mathart/MathArt\_siteMap.html

[rob-bateman]

There are 1 of 2 reasons why you'd want to do this:

1. You really think that g++ is a better compiler than VC++
2. You prefer the mingw ide.

personally i think 1 is a little bit pointless, and 2 can be acheived by making the ide call the vc++ compiler.

[johanhikes]

Hi MathArtSPD... Its being a while since you posted this, but I'm trying to do the exact same thing...

I'm going through the herculean task of compile a *nix library to windows, and I'm stuck on the maya bit... I got all working with mingw  and python just fine, but the maya bit doesnt link and I got the exact same situation you described.

The problem here is that, as its a huge *nix library, its almost impossible to get it running on MSVC, as theres loads of posix specific dependencys and I have a life outside this...

So, as everything is up and running with mingw but the maya bit, I thought about use MSVC to compile the maya bit, but that would create another problem which is make MSVC cope with mingw compiled libraries... I don't know what is worse!!!! LOL

so, I would really appreciate any feedback on your experiences after this post... did you manage to link it properly? any more info you could share?

thanks man

-H

[joojaa]

In either case you have no choice in the matter. For same reason as you want to use minigw maya cant work with it.

[rob-bateman]

Your best bet is to refactor the lib to seperate the posix stuff into a DLL (with a C only interface - no C++!) and compile that with mingw. Make sure you export the relevent functions (that must not pass C++ objects across the DLL boundary! So no args or return types that are classes, or pointers to classes. structs are OK if you are careful about padding).

Having done that, setup a VC++ project for the rest of the code. During the initialisation step, you'll have to manually load the DLL (using LoadModule) and pull out the exported functions from that (using GetProcAddress) and you should be done. A PITA admittedly, but welcome to the fun world of cross-platform development