#include <boost/move/unique_ptr.hpp>
#include <boost/interprocess/offset_ptr.hpp>
#include <boost/intrusive/pointer_traits.hpp>

using boost::interprocess::offset_ptr;

/*
 * Note: this example does not necessarily need to make
 * much sense. It is meant only to show the problem,
 * the reasons why this is needed would be a bit 
 * long to explain, but they have to do with virtuality
 * being forbidden in shared memory.
 */

struct B  {};
struct D : public B {};


struct Deleter
{
  typedef offset_ptr<B> pointer; // e.g. requirement of boost::interprocess::shared_ptr
  void operator() (offset_ptr<void> p)
  {
    // Destroy via custom allocator.
  }
};


int
main()
{  
  boost::movelib::unique_ptr<D, Deleter> ptr (new D);
  offset_ptr<D> d = ptr.get(); // <- fails to compile
}