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I'm trying to late bind my program to a DLL.
I know how to import its methods but in one its header files, I have a definition like this: 

EXTERN_C const IID SomeVariable;

How can I refer to this variable in my program without getting the "unresolved external symbol" error?

Idov
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  • Could you elaborate on the late binding you are doing for functions ? – parapura rajkumar Jan 07 '12 at 20:24
  • I know the function's signature, so I define a function pointer that matches it. Then I just call "GetProcAddress" with the DLL handle and the function's name. I assign the result to an instance of my function pointer and then I can use it as any other function. – Idov Jan 07 '12 at 20:28
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    Odds are very high that this variable is just not getting exported. Use dumpbin.exe /exports on the DLL to double-check. – Hans Passant Jan 07 '12 at 22:46

2 Answers2

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You can use GetProcAddress to get the address of a function or variable.

Jim Rhodes
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See GetProcAddr() at MSDN.

const IID *idp = reinterpret_cast<const IID *>(GetProcAddr(hLibrary, "SomeVariable"));

Now you can refer to SomeVariable via the pointer - just like you can refer to the functions through their pointers. You should, of course, check that the pointer is not null before you actually use it!

Jonathan Leffler
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