Hi, the final lines of digitalmars.hpp read: #if (__DMC__ < 0x840) # if defined(BOOST_ASSERT_CONFIG) # error "Unknown compiler version - please run the configure tests and report the results" # endif #endif Shouldn't it be something like: #if __DMC__ < ??? #error "Compiler not supported or configured - please reconfigure" #endif // // last known and checked version is ...: #if (__DMC__ > 0x840) # if defined(BOOST_ASSERT_CONFIG) # error "Unknown compiler version - please run the configure tests and report the results" # endif BTW, this is common epilogue code in config/compiler/ source files. We might want to factor it out: #define BOOST_CXX_FIRST_SUPPORTED ... #define BOOST_CXX_LAST_KNOWN ... #include "detail/version_boundaries.hpp" ---- // detail/version_boundaries.hpp // (note: no include guards) #if BOOST_CXX_FIRST_SUPPORTED > BOOST_CXX_LAST_KNOWN # error "Boost.Config internal error" #endif #if (BOOST_COMPILER_VERSION < BOOST_CXX_FIRST_SUPPORTED) # error "Compiler version not supported or configured - please reconfigure" #endif #if (BOOST_COMPILER_VERSION > BOOST_CXX_LAST_KNOWN) # if defined(BOOST_ASSERT_CONFIG) # error "Unknown compiler version - please run the configure tests and report the results" # endif --Gennaro.