The current version tests very specifically for bcc 5.64 with an == test. I can't imagine this is correct - i.e. older version of the compiler were supported without workarounds! This patch uses BOOST_TESTED_AT instead. If it really is a regression introduced with the last BCB6 patch, that test should be revised. cvs diff -u -wb -- numeric\conversion\cast.hpp (in directory E:\sourceforge\devel\boost\boost\) Index: numeric/conversion/cast.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/numeric/conversion/cast.hpp,v retrieving revision 1.8 diff -u -w -b -r1.8 cast.hpp --- numeric/conversion/cast.hpp 27 Jun 2005 15:05:12 -0000 1.8 +++ numeric/conversion/cast.hpp 19 Feb 2006 12:19:22 -0000 @@ -22,7 +22,7 @@ #include <boost/detail/workaround.hpp> -#if BOOST_WORKAROUND(BOOST_MSVC, < 1300) || BOOST_WORKAROUND(__BORLANDC__, == 0x564) +#if BOOST_WORKAROUND(BOOST_MSVC, < 1300) || BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x581)) # include<boost/numeric/conversion/detail/old_numeric_cast.hpp> -- AlisdairM