Alexander Nasonov wrote:

Does it mean that your std library doesn't define compile-time contants in std::numeric_limits<T> ?

It does define std::numeric_limits<T>. Something more subtle must be wrong. If I preprocess and compile like this ... % cxx -E -std strict_ansi -tlocal -Iboost include_lcast_precision.cpp | grep -v '^#line ' > z_pp.cpp % cxx -c -std strict_ansi -tlocal z_pp.cpp I get the error below. Does this give a clue? More observations: - cxx 6.5 = EDG 245 - cxx 7.1 = EDG 304 - We also have MIPSpro 7.41 = EDG 245, which doesn't have a problem (but boost.config may work around it in some way...?). cxx: Error: z_pp.cpp, line 20976: constant value is not known typedef ::boost::static_assert_test< sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( !is_specialized_binary || digits < 18446744073709551615U / 30103UL && precision > limits::digits10 + 0UL && precision <= precision_maxarg + 0UL ) >)> boost_static_assert_typedef_63; ----------------------------------------------------------------------------------------------------^ cxx: Error: z_pp.cpp, line 20976: incomplete type is not allowed typedef ::boost::static_assert_test< sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( !is_specialized_binary || digits < 18446744073709551615U / 30103UL && precision > limits::digits10 + 0UL && precision <= precision_maxarg + 0UL ) >)> boost_static_assert_typedef_63; --------------------------------------------------------^ cxx: Error: z_pp.cpp, line 20987: constant value is not known typedef ::boost::static_assert_test< sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( !is_specialized_decimal || precision <= precision_maxarg + 0UL ) >)> boost_static_assert_typedef_74; ----------------------------------------------------------------------------------------------------^ cxx: Error: z_pp.cpp, line 20987: constant value is not known typedef ::boost::static_assert_test< sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( !is_specialized_decimal || precision <= precision_maxarg + 0UL ) >)> boost_static_assert_typedef_74; ------------------------------------------------------------------------------------------------------------------------------^ cxx: Error: z_pp.cpp, line 20987: incomplete type is not allowed typedef ::boost::static_assert_test< sizeof(::boost::STATIC_ASSERTION_FAILURE< (bool)( !is_specialized_decimal || precision <= precision_maxarg + 0UL ) >)> boost_static_assert_typedef_74; --------------------------------------------------------^ cxx: Info: 5 errors detected in the compilation of "z_pp.cpp".