How do I retrieve the type of the base class in C++?

Question

For this particular project, I am not able to use C++11 features (e.g. decltype) because the compiler does not yet support them. I need to be able to provide the current class as a template parameter, preferably within a macro without an argument (see below), without dressing up the class declaration or hiding curly braces, etc.

class Foo: private Bar<Foo> {
   MAGIC //expands to using Bar<Foo>::Baz; and some others
   public:
      void otherFunction();
      //... the rest of the class
};

Ideally, I'd like this to work very much like Qt's Q_OBJECT macro, but without introducing another pre-compile step and associated generated classes. typeid might be useful at runtime, but my goal is to accomplish all of this at build.

How do I write the MAGIC macro so that I don't need to repeat the class name each time?

Answer 1

What about:

template<typename T>
class Base
{
protected:
    typedef Base<T> MagicBaseType;
    namespace Baz { }
};

class Derived1 : private Base<Derived1>
{
    using MagicBaseType::Baz;
}


class Derived1 : private Base<Derived2>
{
    using MagicBaseType::Baz;
}

or, if you can't modify the Base definition, using templates and multiple inheritance

template<typename T>
class Base
{
protected:
    namespace Baz { }
};

template<typename T>
class DerivedTemplate : public T
{
protected:
    typedef typename T BaseType;
}

class Derived : public Base<Derived>, public DerivedTemplate<Base<Derived>>
{
using BaseType::Baz;
}