Hello, In my cvs copy of utf8_codecvt_facet.hpp and utf8_codecvt_facet.cpp files there is CR+CR+LF used as line separator. Also, gcc 3.3.1 (mingw) claims: d:/sources/boost/libs/program_options/src/utf8_codecvt_facet.cpp: In member function `virtual std::codecvt_base::result boost::program_options::detail::utf8_codecvt_facet_wchar_t::do_out(mbstate_t &, const wchar_t*, const wchar_t*, const wchar_t*&, char*, char*, char*&) const ': d:/sources/boost/libs/program_options/src/utf8_codecvt_facet.cpp:229: warning: comparison is always false due to limited range of data type d:/sources/boost/libs/program_options/src/utf8_codecvt_facet.cpp: In function ` int <unnamed>::get_cont_octet_out_count_impl(wchar_t) [with unsigned int s = 4]': d:/sources/boost/libs/program_options/src/utf8_codecvt_facet.cpp:445: warning: comparison is always true due to limited range of data type d:/sources/boost/libs/program_options/src/utf8_codecvt_facet.cpp:451: warning: comparison is always true due to limited range of data type d:/sources/boost/libs/program_options/src/utf8_codecvt_facet.cpp:457: warning: comparison is always true due to limited range of data type Also gcc 3.3.1 generates erros like: C:/CPP/MINGW/include/c++/3.3.1/bits/basic_ios.h: In instantiation of `std::basic_ios<wchar_t, std::char_traits<wchar_t> >': d:/sources/boost/libs/program_options/src/config_file.cpp:145: instantiated from `std::basic_istream<wchar_t, std::char_traits<wchar_t> >' d:/sources/boost/libs/program_options/src/config_file.cpp:145: instantiated from here C:/CPP/MINGW/include/c++/3.3.1/bits/basic_ios.h:67: error: no type named ` pos_type' in `struct std::char_traits<wchar_t>' I found pos_type is defined for char_traits<wchar_t> specialization if _GLIBCPP_USE_WCHAR_T is set, but os_defines.h sets _GLIBCPP_USE_WSTRING only. Is it mingw related problem? Regards, Janusz