How can CString be passed to format string %s?

Question

class MyString
{
public:
    MyString(const std::wstring& s2)
    {
        s = s2;
    }

    operator LPCWSTR() const
    {
        return s.c_str();
    }
pri         


        

Answer 1

Generally speaking it's undefined behavior. According to this article Visual C++ just invokes the conversion from CString to a POD type to cover you - that is permissible implementation of undefined behavior.