Hi, I have adapted the Bitfield library from Emile Cormier with its permision. Boost.Bitfield consists of: a.. a generic bitfield traits class providing generic getter and setter methods. b.. a BOOST_BITFIELD_DCL macro making easier the definition of the bitfield traits and the bitfield getter and setter functions. struct X { typedef boost::ubig_32 storage_type; storage_type d0; typedef unsigned int value_type; BOOST_BITFIELD_DCL(storage_type, d0, unsigned int, d00, 0, 10); BOOST_BITFIELD_DCL(storage_type, d0, unsigned int, d01, 11, 31); }; The library is quite stable but I want to add some test with Boost.Endian before adding it to the formal review schedule list. Here is the link from which you can get the library code + documentation + test https://svn.boost.org/trac/boost/wiki/LibrariesUnderConstruction#Boost.Bitfi... I'd appreciate if people could take a look, test it on their compiler and give me some feedback. Thanks for all, _____________________ Vicente Juan Botet Escribá