How do I create and use a class arrow operator?

So, after researching everywhere for it, I cannot seem to find how to create a class arrow operator, i.e.,

class Someclass
{
  operator-> ()  /* ? */
  {
  }
};

I just need to know how to work with it and use it appropriately. - what are its inputs? - what does it return? - how do I properly declare/prototype it?