// In header: <boost/intrusive/pointer_traits.hpp>
template<typename T> 
struct pointer_traits<T *> {
  // types
  typedef T              element_type;   
  typedef T *            pointer;        
  typedef std::ptrdiff_t difference_type;
  typedef T &            reference;      
  typedef U *            rebind;         
  // member classes/structs/unions
  template<typename U> 
  struct rebind_pointer {
    // types
    typedef U * type;
  };
  // public static functions
  static pointer pointer_to(reference);
  template<typename U> static pointer static_cast_from(U *);
  template<typename U> static pointer const_cast_from(U *);
  template<typename U> static pointer dynamic_cast_from(U *);
};