Thanks a lot for the gcc warning workarounds! It is highly appreciated. Unfortunately, now g++ 3.2 doesn't work anymore. See below. I think gcc 3.3 and higher are fine. Ralf g++ (GCC) 3.2.3 20030502 (Red Hat Linux 3.2.3-20) boost svn rev. 45087 % cat te.cpp #include <boost/throw_exception.hpp> % g++ -Wall -Iboost -c te.cpp In file included from boost/boost/exception/enable_error_info.hpp:9, from boost/boost/throw_exception.hpp:39, from te.cpp:1: boost/boost/exception/exception.hpp: In instantiation of `boost::detail::sp_convertible<boost::exception_detail::error_info_container, boost::exception_detail::error_info_container>': boost/boost/exception/exception.hpp:75: instantiated from `boost::detail::sp_enable_if_convertible<boost::exception_detail::error_info_container, boost::exception_detail::error_info_container>' boost/boost/exception/exception.hpp:75: instantiated from here boost/boost/exception/exception.hpp:75: invalid use of undefined type `struct boost::detail::sp_convertible<boost::exception_detail::error_info_container, boost::exception_detail::error_info_container>' boost/boost/detail/sp_convertible.hpp:27: declaration of `struct boost::detail::sp_convertible<boost::exception_detail::error_info_container, boost::exception_detail::error_info_container>' boost/boost/exception/exception.hpp:75: enumerator value for `value' not integer constant