I'm having a load of trouble getting Boost.Integer to play nice with the Borland/Codegear compilers, for example given: void print_val(long long l) { std::cout << std::hex << static_cast<int>((l & 0xFFFFFFFF00000000LL) >> 32); std::cout << std::hex << static_cast<int>((l & 0xFFFFFFFFLL)) << std::endl; } And then: static const long long MaxValue = SCHAR_MAX; static const long long sll = _LLONG_MAX; const long long cll = _LLONG_MAX; long long ll = _LLONG_MAX; BOOST_TEST(MaxValue <= ::boost::integer_traits<boost::long_long_type>::const_max); // fails BOOST_TEST(MaxValue <= _LLONG_MAX); // passes BOOST_TEST(MaxValue <= sll); //fails BOOST_TEST(MaxValue <= cll); // fails BOOST_TEST(MaxValue <= ll); // passes print_val(_LLONG_MAX); // OK prints 7fffffffffffffff print_val(ll); // OK prints 7fffffffffffffff print_val(sll); // Oh no, prints ffffffffffffffff print_val(cll); // Oh no, prints ffffffffffffffff So as soon as a long long is declared const (whether static or not) it seems to be incapable of actually holding a sensible value!! Anyone got any ideas what's going on or any workarounds? Thanks, John. PS I'm still using Borland-5.8.2, but judging by the test matrix results the latest versions have similar issues.