Playing with the release candidate of MSVC 10, and I'm noticing boost 1.42.0 is not using any C++0x features. Has this been discussed before, or is there a reason for this? Taking a peek at boost/config/compiler/visualc.hpp, I see the following: #if _MSC_VER < 1600 #define BOOST_NO_AUTO_DECLARATIONS #define BOOST_NO_AUTO_MULTIDECLARATIONS #define BOOST_NO_DECLTYPE #define BOOST_NO_LAMBDAS #define BOOST_NO_RVALUE_REFERENCES #define BOOST_NO_STATIC_ASSERT #define BOOST_NO_NULLPTR #endif // _MSC_VER < 1600 // C++0x features not supported by any versions #define BOOST_NO_CHAR16_T #define BOOST_NO_CHAR32_T #define BOOST_NO_CONCEPTS #define BOOST_NO_CONSTEXPR #define BOOST_NO_DEFAULTED_FUNCTIONS #define BOOST_NO_DELETED_FUNCTIONS #define BOOST_NO_EXPLICIT_CONVERSION_OPERATORS #define BOOST_NO_EXTERN_TEMPLATE #define BOOST_NO_FUNCTION_TEMPLATE_DEFAULT_ARGS #define BOOST_NO_INITIALIZER_LISTS #define BOOST_NO_RAW_LITERALS #define BOOST_NO_SCOPED_ENUMS #define BOOST_NO_SFINAE_EXPR #define BOOST_NO_TEMPLATE_ALIASES #define BOOST_NO_UNICODE_LITERALS #define BOOST_NO_VARIADIC_TEMPLATES It almost appears as if the #else was simply forgotten on the first #if. Can't we safely change the first conditional to the following? #if _MSC_VER < 1600 #define BOOST_NO_AUTO_DECLARATIONS #define BOOST_NO_AUTO_MULTIDECLARATIONS #define BOOST_NO_DECLTYPE #define BOOST_NO_LAMBDAS #define BOOST_NO_RVALUE_REFERENCES #define BOOST_NO_STATIC_ASSERT #define BOOST_NO_NULLPTR #else #define BOOST_HAS_AUTO_DECLARATIONS #define BOOST_HAS_AUTO_MULTIDECLARATIONS #define BOOST_HAS_DECLTYPE #define BOOST_HAS_LAMBDAS #define BOOST_HAS_RVALUE_REFERENCES #define BOOST_HAS_STATIC_ASSERT #define BOOST_HAS_NULLPTR #endif // _MSC_VER < 1600 Zach