Question

I have tried a simple C++ CException implementation class, deriving from std::exception. What did I do wrong, what should I add more, what should I improve on? What is it more to c++ exceptions that one should take into consideration? The aim is to make it as much platform independent as possible. The code follows:
Edited:

class CeException: public std::exception {
public:
    char* getascii(const wchar_t* msg)
    {
        char* pasc = new char[wcslen(msg) + 1 ];
        wcstombs(pasc, msg, wcslen(msg) + 1);
        return pasc;
    }
    CeException(const wchar_t* msg, char* pasc = NULL ):
    exception(pasc = getascii(msg))
    {

        delete[] pasc;
    }
    CeException(const string msg) 
    {   

    }
    virtual ~CeException()
    {       
    }
    BOOL GetErrorMessage(LPTSTR lpszError, UINT nMaxError, PUINT pnHelpContext = NULL )
    {

        const char* pasc = this->what();

        wchar_t* puni = new wchar_t[strlen(pasc)+1];
            mbstowcs(puni,pasc, strlen(pasc) + 1);

        wcscpy_s(lpszError,nMaxError, puni);
        delete[] puni;
        return 0;
    }
    void Delete()
    {
        delete this;
    }


};

I have edited with my final implementation, using your indications.

Answer 1

Typically you don’t need to implement methods inside exception class, so it might look something like this:

class YourException : public std::runtime_error
{
public:
    explicit YourException(const std::string & msg) :
        std::runtime_error(msg)
    {
    }
};

I don’t understand the reasons to have other methods.

You should not throw exception from it’s constructor. Instead, client code should throw your exception:

    throw YourException("Some error");