Hi all, the boost::math::signbit function in trunk fails for an argument of -NAN. #include <boost/math/special_functions/sign.hpp> int main() { using boost::math::signbit; BOOST_ASSERT(signbit(-std::numeric_limits<double>::quiet_NaN())); return 0; } I'd expect to get a '1' back, but the function returns zero and the assertion fails. I know it worked while using Jon Rade's floating point utilities library from the vault. Does this have been integrated? Regards Hartmut