C4275 warning in Visual Studio

Question

I get this warning when compiling my code in VS2008

warning C4275: non dll-interface class 'std::runtime_error' used as base for dll-interface class 'MyException' 2> c:\Program Files (x86)\Microsoft Visual Studio 9.0\VC\include\stdexcept(148) : see declaration of 'std::runtime_error'

My class is defined as

class MyException : public std::runtime_error

Answer 1

MSDN: http://msdn.microsoft.com/en-us/library/3tdb471s.aspx

"An exported class [as in DLL] was derived from a class that was not exported [as in DLL]."

Apparently you are declaring MyException to be exportable from a DLL (by using: __declspec(dllexport)), while std::runtime_error is not exportable. Consider if MyException really needs to be exportable. However, if none of the issues listed on the above page apply to your specific case, then you can disregard that warning--just be aware of the issues.