Hi there, same to my former email. The extension example does not compile with VC7.1. Here are the errors: \boost\libs\fusion\example\extension\test_example.cpp(25) : error C2039: 'is_associative' : is not a member of 'boost::fusion::traits' \boost\libs\fusion\example\extension\test_example.cpp(25) : error C2059: syntax error : ')' \boost\libs\fusion\example\extension\test_example.cpp(26) : error C2653: 'traits' : is not a class or namespace name \boost\libs\fusion\example\extension\test_example.cpp(26) : error C2059: syntax error : ')' \boost\libs\fusion\example\extension\test_example.cpp(26) : error C2143: syntax error : missing ';' before '}' \boost\libs\fusion\example\extension\test_example.cpp(26) : error C2059: syntax error : '}' \boost\libs\fusion\example\extension\test_example.cpp(27) : error C2653: 'traits' : is not a class or namespace name \boost\libs\fusion\example\extension\test_example.cpp(27) : error C2059: syntax error : ')' \boost\libs\fusion\example\extension\test_example.cpp(27) : error C2143: syntax error : missing ';' before '}' \boost\libs\fusion\example\extension\test_example.cpp(27) : error C2059: syntax error : '}' \boost\libs\fusion\example\extension\test_example.cpp(29) : error C2061: syntax error : identifier 'begin' \boost\libs\fusion\example\extension\test_example.cpp(29) : error C2143: syntax error : missing ')' before '==' \boost\libs\fusion\example\extension\test_example.cpp(29) : error C2059: syntax error : ')' \boost\libs\fusion\example\extension\test_example.cpp(29) : error C2457: '__FUNCSIG__': predefined macro cannot appear outside of a function body \boost\libs\fusion\example\extension\test_example.cpp(29) : error C2059: syntax error : ')' \boost\libs\fusion\example\extension\test_example.cpp(29) : error C2501: 'boost::detail::test_failed_impl' : missing storage-class or type specifiers \boost\libs\fusion\example\extension\test_example.cpp(29) : error C2365: 'boost::detail::test_failed_impl' : redefinition; previous definition was a 'function' c:\boost\boost\detail\lightweight_test.hpp(40) : see declaration of 'boost::detail::test_failed_impl' \boost\libs\fusion\example\extension\test_example.cpp(29) : error C2185: 'boost::detail::test_failed_impl' : illegal based allocation \boost\libs\fusion\example\extension\test_example.cpp(29) : fatal error C1903: unable to recover from previous error(s); stopping compilation Christian