Windows CE does not supply the ANSI version of FormatMessage (only FormatMessageW). The attached patch substitutes FormatMessageW-based code in this case. Thanks, -Dave Index: error_code.cpp =================================================================== --- error_code.cpp (revision 40672) +++ error_code.cpp (working copy) @@ -345,6 +345,7 @@ //Chris std::string system_error_category::message( int ev ) const { +#if !defined(BOOST_NO_ANSI_APIS) LPVOID lpMsgBuf; ::FormatMessageA( FORMAT_MESSAGE_ALLOCATE_BUFFER | @@ -359,6 +360,27 @@ ); std::string str( static_cast<LPCSTR>(lpMsgBuf) ); ::LocalFree( lpMsgBuf ); // free the buffer +#else + LPVOID lpMsgBuf; + ::FormatMessageW( + FORMAT_MESSAGE_ALLOCATE_BUFFER | + FORMAT_MESSAGE_FROM_SYSTEM | + FORMAT_MESSAGE_IGNORE_INSERTS, + NULL, + ev, + MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language + (LPWSTR) &lpMsgBuf, + 0, + NULL + ); + + int num_chars = (wcslen( static_cast<LPCWSTR>(lpMsgBuf) ) + 1) * 2; + LPSTR narrow_buffer = (LPSTR)_alloca( num_chars ); + ::WideCharToMultiByte(CP_ACP, 0, static_cast<LPCWSTR>(lpMsgBuf), -1, narrow_buffer, num_chars, NULL, NULL); + + std::string str( narrow_buffer ); + ::LocalFree( lpMsgBuf ); // free the buffer +#endif while ( str.size() && (str[str.size()-1] == '\n' || str[str.size()-1] == '\r') ) str.erase( str.size()-1 );