When compiling demo.cpp I get the warnings: /home/test/boost/include/boost-1_32/boost/archive/detail/common_iarchive.hpp: In member function `void boost::archive::detail::common_iarchive<Archive>::init() [with Archive = boost::archive::text_iarchive]': /home/test/boost/include/boost-1_32/boost/archive/text_iarchive.hpp:69: instantiated from `boost::archive::text_iarchive_impl<Archive>::text_iarchive_impl(std::istream&, unsigned int) [with Archive = boost::archive::text_iarchive]' /home/test/boost/include/boost-1_32/boost/archive/text_iarchive.hpp:82: instantiated from here /home/test/boost/include/boost-1_32/boost/archive/detail/common_iarchive.hpp:75: warning: choosing `boost::archive::version_type::operator unsigned int&()' over ` boost::archive::version_type::operator unsigned int() const' /home/test/boost/include/boost-1_32/boost/archive/detail/common_iarchive.hpp:75: warning: for conversion from `boost::archive::version_type' to `unsigned int' /home/test/boost/include/boost-1_32/boost/archive/detail/common_iarchive.hpp:75: warning: because conversion sequence for the argument is better I'm using this compiler: g++ (GCC) 3.2.3 20030502 (Red Hat Linux 3.2.3-52) I'd like a way to silence these warnings assuming this isn't a problem on my system. I apologize if this was discussed previously, but I couldn't find any means to search the mailing list archive.