Hi all, try to compile and run all the regex algoritm examples lead by all examples to the same error (s. below). Has somebody an idea, what kind of define is missing or wrong? I try it with MSVC++ 6 SP5 on Windows 2000. thanks for any help, regards Arno switch on BOOST_REGEX_DIAG Compiling... Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 12.00.8804 for 80x86 Copyright (C) Microsoft Corp 1984-1998. All rights reserved. cl /MDd /W3 /Gm /GR /GX /ZI /Od /I "..\Basics" /I "..\Basics\boost\include\boost - 1_31" /D "WIN32" /D "_DEBUG" /D "_CONSOLE" /D "_MBCS" /Fo"Debug/" /Fd"Debug/" /F D /GZ /c LibraryTest.cpp LibraryTest.cpp Linking to lib file: libboost_regex-vc6-mt-gd-1_31.lib ..\basics\boost\include\boost-1_31\boost\regex\config.hpp(596) : warning C4003: not enough actual parameters for macro 'BOOST_DO_STRINGIZE' BOOST_REGEX_DECL set as: BOOST_REGEX_CALL set as: __cdecl BOOST_REGEX_CCALL set as: __cdecl Using Win32 locale in regex traits class Using Version 4 regex code ..\boost\include\boost-1_31\boost\regex\v4\regex_traits.hpp(955) : error C2039: 'mbstate_t' : is not a member of 'std' ..\basics\boost\include\boost-1_31\boost\regex\v4\char_regex_traits.hpp(34) : error C2504: 'regex_traits' : base class undefined ..\basics\boost\include\boost-1_31\boost\regex\v4\char_regex_traits.hpp (34) : see reference to class template instantiation 'deprecated::char_regex_traits_i<charT>' being compiled ..\basics\boost\include\boost-1_31\boost\regex\v4\char_regex_traits.hpp(34) : error C2143: syntax error : missing ',' before '<' ..\basics\boost\include\boost-1_31\boost\regex\v4\char_regex_traits.hpp (34) : see reference to class template instantiation 'deprecated::char_regex_traits_i<charT>' being compiled ..\basics\boost\include\boost-1_31\boost\regex\v4\char_regex_traits.hpp(34) : error C2059: syntax error : '<' ..\basics\boost\include\boost-1_31\boost\regex\v4\char_regex_traits.hpp (34) : see reference to class template instantiation 'deprecated::char_regex_traits_i<charT>' being compiled ..\basics\boost\include\boost-1_31\boost\regex\v4\char_regex_traits.hpp(75) : fatal error C1506: unrecoverable block scoping error Error executing cl.exe. LibraryTest.obj - 5 error(s), 1 warning(s)