[SOLVED] Error link 2001 on CLSID from my another DLL

Error link 2001 on CLSID from my another DLL

I have 2 DLLs. I want create instance of class in my second DLL that I declare at .idl file of first library. But I get Error Link 2001 on CLSID, when try to link second DLL. I'm linking with first DLL, so I don't know why I'm getting this error.

Stock.idl

Declaration of class

[uuid(61AF2A3E-8B04-4161-B978-5776BFDF7DB5), helpstring("StockObjectManager Class")]
coclass StockObjectManager
{
    [default] interface IStockObjectManager;
    interface ISQLBase;
};

Generated Files:

Stock.h

EXTERN_C const CLSID CLSID_MazStockObjectManager;

Stock_i.c

MIDL_DEFINE_GUID(CLSID, CLSID_StockObjectManager,0x61AF2A3E,0x8B04,0x4161,0xB9,0x78,0x57,0x76,0xBF,0xDF,0x7D,0xB5);

FIleFromSecondDll.cpp

CComPtr<IStockObjectManager> m_SOManager;
m_SOManager.CoCreateInstance(CLSID_StockObjectManager); // getting Error Link 2001 unresolved external symbol "_CLSID_StockObjectManager"

I want to understand why I'm getting this error and fix it. Of course, I can just #include "Stock_i.c", but it isn't good solution, I guess.

Solution

in Stock.h must be not only

EXTERN_C const CLSID CLSID_MazStockObjectManager;

but also

#ifdef __cplusplus
class DECLSPEC_UUID("61AF2A3E-8B04-4161-B978-5776BFDF7DB5") MazStockObjectManager;
#endif

so and use

CComPtr<IStockObjectManager> m_SOManager;
m_SOManager.CoCreateInstance(__uuidof(MazStockObjectManager));