Hello, This may be more appropriate for the devel list, but someone just pointed out on this list that an endian library has been submitted for approval. I've *just* needed classes like this (actually I wrote my own similar classes), and decided to see how the Boost library stacked up. It looks quite nice, and I'd be excited to see this included. One suggestion I would make is that the endian classes should not have constructors. As of version 0.5, trying to put them into a union causes a compiler error. Take the struct from the example, and add a union: struct header { big4_t file_code; big4_t file_length; little4_t version; little4_t shape_type; union { big4_t foo; little4_t bar; } baz; }; I get the following errors: endian_example.cpp:37: error: member 'boost::integer::big4_t <unnamed>::header::<anonymous union>::foo' with constructor not allowed in union endian_example.cpp:38: error: member 'boost::integer::little4_t <unnamed>::header::<anonymous union>::bar' with constructor not allowed in union By removing all constructors, the errors go away. I cam across this very issue when developing my classes, and found the answer in this comp.lang.c++.moderated post: <http://groups.google.com/group/comp.lang.c++.moderated/msg/ 103835a7b493723e?hl=en&> As an experiment, I modified boost/integer/endian.hpp to remove the constructors, and add an operator=() to see if this worked, and it did: template <typename T, std::size_t n_bytes> class endian< big, T, n_bytes, unaligned > : cover_operators< endian< big, T, n_bytes >, T > { public: typedef T value_type; operator T() const { return detail::load_big_endian<T, n_bytes>(bytes); } void operator=(T i) { detail::store_big_endian<T, n_bytes> (bytes, i); } private: char bytes[n_bytes]; }; I'd suggest making this change to all classes so that they can be used in unions. -Dave