Here's what I'm trying (to redo integer_test.cpp): //============================== #include <boost/config.hpp> #include <boost/limits.hpp> #include <boost/integral_c.hpp> #include <boost/mpl/list.hpp> #include <boost/mpl/transform.hpp> #include <boost/static_assert.hpp> #include <boost/type_traits.hpp> #include <climits> namespace { // List all the conventional integral types, without the ones that are like // a strong-typedef of a lower type typedef boost::mpl::list<unsigned char #if USHRT_MAX > UCHAR_MAX , unsigned short #endif #if UINT_MAX > USHRT_MAX , unsigned int #endif #if ULONG_MAX > UINT_MAX , unsigned long #endif #if defined(BOOST_HAS_LONG_LONG) && ((ULLONG_MAX > ULONG_MAX) || (ULONGLONG_MAX > ULONG_MAX)) , boost::ulong_long_type #elif defined(BOOST_HAS_MS_INT64) && (0xFFFFFFFFFFFFFFFFui64 > ULONG_MAX) , unsigned __int64 #endif > distinct_unsigned_types; typedef boost::mpl::transform<distinct_unsigned_types, boost::make_signed<boost::mpl::_1> >::type distinct_signed_types; // New type list: integral type -> (wrapped) number of bits template < typename T > struct type_to_digit_count : boost::mpl::integral_c<int, std::numeric_limits<T>::digits> { }; typedef boost::mpl::transform<distinct_unsigned_types, type_to_digit_count<boost::mpl::_1> >::type distinct_integral_bit_counts; BOOST_STATIC_ASSERT ( (boost::is_same<distinct_integral_bit_counts, boost::mpl::list_c<int, 8, 16, 32, 64> >) ); } //============================== I originally did not have that last line there with the "BOOST_STATIC_ASSERT," but I put it in after some errors when doing a compiler-sanity check while coding. I cleaned up the other errors, but the compiler complains that the first argument of "is_same," i.e. "distinct_integral_bit_counts," is an invalid template argument. I don't think my definition of "type_to_digit_count" is lambda-safe, like "make_signed" is. How do I get it that way? (Or is the problem in the definition of "distinct_integral_bit_counts"?) -- Daryle Walker Mac, Internet, and Video Game Junkie darylew AT hotmail DOT com