time_duration in Boost 1.35.0 has an is_negative() method. I need exactly the opposite: time_duration td; while (td.is_positive()) { // reduce td in some way } I am aware, that I can use td.ticks()>0, but since is_negative() already exists, it would be nice to have also the following methods for completeness and symmetry: bool time_duration::is_positive() const bool time_duration::is_zero() const So for all non special value time_duration instances one of the above methods would return true, the other two false. Best regards, Peter.