Thank you for anyone try to help me.

I managed to get four files by compiling the *.idl file.But I have some problems in compiling the four files and the *.def file.When these files were being linked,I was told the following information: MyProxy.def : error LNK2001: unresolved external symbol DllRegisterServer MyProxy.def : error LNK2001: unresolved external symbol DllUnregisterServer I think the *.idl file will define the two functions for me.Is it true?And what's wrong?Do I have to define the two functions on myself?Inform me of the details,please.Many thanks for you read my question.I'm waiting for your reply.Thank you for reading my question.:eek:

Thank you for your reply.

The following is the simplified code: #include interface ix:IUnknown { virtual void __stdcall fx()=0; }; class Try:public ix { public: HRESULT __stdcall QueryInterface(IID& iid,void** ppv){return S_OK;} virtual ULONG __stdcall AddRef(){return 0;} virtual ULONG __stdcall Release(){return 0;} virtual void __stdcall fx(){} Try(){} }; void f() { Try ptry; } --------------------Configuration: try - Win32 Debug------- d:\files\vc\com\try\try.cpp(23) : error C2259: 'Try' : cannot instantiate abstract class due to following members: d:\files\vc\com\try\try.cpp(7) : see declaration of 'Try' d:\files\vc\com\try\try.cpp(23) : warning C4259: 'long __stdcall IUnknown::QueryInterface(const struct _GUID &,void ** )' : pure virtual function was not defined d:\microsoft visual studio\vc98\include\unknwn.h(109) : see declaration of 'QueryInterface' d:\files\vc\com\try\try.cpp(23) : error C2259: 'Try' : cannot instantiate abstract class due to following members: d:\files\vc\com\try\try.cpp(7) : see declaration of 'Try' d:\files\vc\com\try\try.cpp(23) : warning C4259: 'long __stdcall IUnknown::QueryInterface(const struct _GUID &,void ** )' : pure virtual function was not defined d:\microsoft visual studio\vc98\include\unknwn.h(109) : see declaration of 'QueryInterface' ********************************************************** I really don't know what's wrong with the code. :confused: :confused: :confused: