Hi, Upon trying to create the new shifted_allocator class that is to be passed as a template parameter on STL containers, I got stuck in a circle or errors. It turns out there was no way to replace internal pointers used by containers with smart pointers... which is very unfortunate. There are different solution I could take but hopefully I won't need them. By trying compiling shifted_ptr_test2.cpp in the Sandbox we'll get the following errors. I believe shifted_allocator (in shifted_allocator.hpp) should be represented the way it is but I may likely got something wrong because I browsed quickly but I haven't seen the verdict on this in previous posts: ...stl_vector.h: In member function `__gnu_cxx::__normal_iterator<typename _Alloc::const_pointer, std::vector<_Tp, _Alloc> > std::vector<_Tp, _Alloc>::begin() const [with _Tp = boost::detail::sh::shifted_ptr<vector>, _Alloc = boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector>

]': ...stl_vector.h:221: instantiated from `std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&) [with _Tp = boost::detail::sh::shifted_ptr<vector>, _Alloc = boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector> >]' shifted_ptr_test2.cpp:66: instantiated from here ...stl_vector.h:322: error: no matching function for call to `__gnu_cxx::__normal_iterator<const boost::detail::sh::shifted<boost::detail::sh::shifted_ptr<vector> >*, std::vector<boost::detail::sh::shifted_ptr<vector>, boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector> > > ::__normal_iterator(boost::detail::sh::shifted_ptr<vector>* const&)' ...stl_iterator.h:587: note: candidates are: __gnu_cxx::__normal_iterator<const boost::detail::sh::shifted<boost::detail::sh::shifted_ptr<vector> >*, std::vector<boost::detail::sh::shifted_ptr<vector>, boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector> > > ::__normal_iterator(const __gnu_cxx::__normal_iterator<const boost::detail::sh::shifted<boost::detail::sh::shifted_ptr<vector> >*, std::vector<boost::detail::sh::shifted_ptr<vector>, boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector> > > >&) ...stl_iterator.h:603: note: __gnu_cxx::__normal_iterator<_Iterator, _Container>::__normal_iterator(const _Iterator&) [with _Iterator = const boost::detail::sh::shifted<boost::detail::sh::shifted_ptr<vector> >*, _Container = std::vector<boost::detail::sh::shifted_ptr<vector>, boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector> > >] ...stl_iterator.h:600: note: __gnu_cxx::__normal_iterator<_Iterator, _Container>::__normal_iterator() [with _Iterator = const boost::detail::sh::shifted<boost::detail::sh::shifted_ptr<vector> >*, _Container = std::vector<boost::detail::sh::shifted_ptr<vector>, boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector> > >] ...stl_vector.h: In member function `__gnu_cxx::__normal_iterator<typename _Alloc::const_pointer, std::vector<_Tp, _Alloc> > std::vector<_Tp, _Alloc>::end() const [with _Tp = boost::detail::sh::shifted_ptr<vector>, _Alloc = boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector> ]': ...stl_vector.h:221: instantiated from `std::vector<_Tp, _Alloc>::vector(const std::vector<_Tp, _Alloc>&) [with _Tp = boost::detail::sh::shifted_ptr<vector>, _Alloc = boost::shifted_allocator<boost::detail::sh::shifted_ptr<vector> >]'

The Vault version presents the same code except the comment of line 67 & 68 in shifted_ptr_test2.cpp will need to be swapped: http://www.boostpro.com/vault/index.php?action=downloadfile&filename=shifted_ptr.zip&directory=Memory -Phil