Hello! The example for boost::numeric_cast contains documentation, which clearly is wrong and stumbles the reader. On http://boost.org/libs/numeric/conversion/doc/numeric_cast.html#numeric_cast we have the lines unsigned long l=std::numeric_limits<unsigned long>::max(); // This works, because unsigned integral types cannot cause overflow. unsigned char c=numeric_cast<unsigned char>(l); which contradict the behaviour and the range checking logic presented on http://boost.org/libs/numeric/conversion/doc/converter.html#rchklogic Btw.: Further on the #include directive, namely #include <boost/numeric_cast.hpp> should be corrected to #include <boost/numeric/conversion/cast.hpp> Greetings from Bremen, Daniel Krügler