In boost/detail/numeric_traits.hpp, integer_traits can be used to find the difference_type for an int type, in aC++, I get a long long -- I don't think that's the correct result, but can somebody please tell me why not? Thanks! integer_traits<int>::difference_type // long long?? I expect this to be an int Here's why: template <class Integer, bool = true> struct integer_traits { ... typedef typename if_true<(int(x::is_signed) // true && (!int(x::is_bounded) // true || (int(x::digits) + 1 >= digit_traits<boost::intmax_t>::digits))) // false >::template then< Integer, typename if_true<(int(x::digits) + 1 < digit_traits<signed int>::digits)>::template then< // false signed int, typename if_true<(int(x::digits) + 1 < digit_traits<signed long>::digits)>::template then< // false signed long, // else intmax_t // this is long long >::type>::type>::type difference_type; ... } -Jerry