#include <iostream>
static const std::size_t offset_type_alignment = 0;

template<class T, class U>
struct pointer_to_other;

template<class T, class U, template<class> class Sp>
struct pointer_to_other< Sp<T>, U >
{
   typedef Sp<U> type;
};

template <class PointedType, class DifferenceType, class OffsetType, std::size_t OffsetAlignment>
class offset_ptr
{
};
template <class T, class DifferenceType = std::ptrdiff_t, class OffsetType = std::size_t, std::size_t Alignment = offset_type_alignment>
class offset_ptr;


template<class T, class T2, class T3, std::size_t A, class U>
struct pointer_to_other<offset_ptr<T, T2, T3, A>, U >
{
   typedef offset_ptr<U, T2, T3, A> type;
};


template<class VoidPointer>
class message_queue_t
{
   typedef VoidPointer                                                 void_pointer;
   typedef typename pointer_to_other<void_pointer, char>::type	       char_ptr;
};

int main()
{
message_queue_t< offset_ptr<void, std::ptrdiff_t, std::size_t, offset_type_alignment> > test;


}