Hello, The Boost Multi_Array library produces some 64-bit related warnings when used with Visual C++.NET. It seems to me that these warnings are valid and correspond to real 64-bit problems. To get rid of these annoying warnings, I have fixed two minor inconsistencies in multi_array/iterator.hpp and multi_array/multi_array_ref.hpp, but that was not enough. I also had to change the definition of boost::detail::multi_array::index in multi_array/types.hpp from "typedef int index;" to "typedef std::ptrdiff_t index;". There might be better solutions, but it was the best I could think of, because std::ptrdiff_t is a signed type and will adapt to a 64-bit environment. Index: multi_array/iterator.hpp =================================================================== --- multi_array/iterator.hpp (Revision 1040) +++ multi_array/iterator.hpp (Arbeitskopie) @@ -98,7 +98,7 @@ array_iterator() {} - array_iterator(int idx, TPtr base, const size_type* extents, + array_iterator(index idx, TPtr base, const size_type* extents, const index* strides, const index* index_base) : idx_(idx), base_(base), extents_(extents), Index: multi_array/types.hpp =================================================================== --- multi_array/types.hpp (Revision 1040) +++ multi_array/types.hpp (Arbeitskopie) @@ -26,7 +26,7 @@ // needed typedefs typedef std::size_t size_type; -typedef int index; +typedef std::ptrdiff_t index; } // namespace multi_array } // namespace detail Index: multi_array/multi_array_ref.hpp =================================================================== --- multi_array/multi_array_ref.hpp (Revision 1040) +++ multi_array/multi_array_ref.hpp (Arbeitskopie) @@ -389,7 +389,7 @@ // Calculate the array size num_elements_ = std::accumulate(extent_list_.begin(),extent_list_.end(), - 1,std::multiplies<index>()); + size_type(1),std::multiplies<size_type>()); #if 0 assert(num_elements_ != 0); #endif