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I have a DLL and lib file. I've included them in the root source directory and added the lib reference through Additional Dependencies. However, I get the following error:

1>main.obj : error LNK2001: unresolved external symbol "class game::c_State game::state" (?state@game@@3Vc_State@1@A)
fatal error LNK1120: 1 unresolved externals
which would be referencing this from "engine.h":
extern __declspec(dllexport) c_State state;
In "state.cpp" (from the DLL's source,) it is declared as
namespace game
    c_State state;
    //clipped for relevance
Could it be that I need to place the DLL somewhere specific? Does Windows know where to look? I found nowhere in the properties to specifically reference the DLL file, only the lib file.
Also, do I need a __declspec(dllexport) when declaring variables, or only functions?
Thanks in advance!
You have to apply __declspec(dllexport) to the definition, not the declaration.  Also, the declaration needs __declspec(dllimport) in the other project.  So in the .h file:
#undef EXPORT
#ifdef FOO_EXPORTS
#  define EXPORT __declspec(dllexport)
#else
#  define EXPORT __declspec(dllimport)
#endif
extern EXPORT int shared;
In the DLL source code file:
__declspec(dllexport) int shared;
And in the DLL project use Project + Properties, C/C++, Proprocessor.  Add FOO_EXPORTS to the preprocessor definitions.
                Thanks for that. I'm assuming the ifdef and else statements are for portability. If I decided to compile the engine under Linux I could simply remove FOO_EXPORTS and then it would (assuming otherwise portable code) compile.
– screennameless
                Feb 2, 2012 at 1:22
        
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