Question

I have a slight problem where my << operator is not being called correctly.

This is what I have:

class SomeInterface
{
   friend std::ostream& operator<<(std::ostream& str, const SomeInterface& data);

   protected:
      virtual void print(ostream& str) const = 0;
};

inline std::ostream& operator<< (std::ostream& o, SomeInterface const& b)
{
  b.print(o);
  return o;
}
}

Calling code looks something like:

SomeInterface* one  = new someConcrete ();
cout << one;

The << overloaded function I was hoping would get called on the interface is not, let alone dispatching through to the derived class.

Answer 1

Try:

cout << *one;

Your code is asking to print the pointer, while your operator<< takes a const SomeInterface& reference.