Two lines have been the bane of my existence for the last week or so - both cheerfully given by the linker... quinkin.obj : error LNK2005: "struct _GUID d3dgid" (?d3dgid@@3U_GUID@@A) already defined in 3dapp.obj Debug/Quinkin.exe : fatal error LNK1169: one or more multiply defined symbols found d3dgid is defined as such : GUID d3dgid; If I comment out all uses of the variable except the declaration, the errors persist. The header file declarations, where the above line resides, is safely encapsulated by #ifndef ... #endif. I have tried re-installing the SDK, trying static declarations... but nothing seems to make a difference. Am I not looking in the right place? Any help would be greatly appreciated as I attempt to make the transition from 2D to 3D. Thanks. Steele.

maybe you have to include the file dxguid.lib into the list of
Object/Library modules of the Project settings.

Project---->Settings---->Link (and there you can include dxguid.lib into the modules line).

In the .h file you should use:

extern GUID d3dgid; 

And in ONE .cpp file you need to define it w/o the extern:

GUID d3dgid; 

Thanks guys! It seemed to be a bit of all of them! With a bit of shuffling about with includes, an extern declaration and rebuild, I have it working.
Ta for the help.
Steele.
Woooohoooooooooo!!!