Hello, I found the solution. I had to specialize the min and max as follows for my UDT. It now works as it always did :) acc_sample std::numeric_limits::min() { return (acc_sample(1000, std::numeric_limits<double>::min())); } acc_sample std::numeric_limits::max() { return (acc_sample(1000, std::numeric_limits<double>::max())); } -dhruva From Chandigarh to Chennai - find friends all over India. Go to http://in.promos.yahoo.com/groups/citygroups/