Various types of calculations with times and time durations. int main() { using namespace boost::posix_time; using namespace boost::gregorian; date d(2002,Feb,1); //an arbitrary date //construct a time by adding up some durations durations ptime t1(d, hours(5)+minutes(4)+seconds(2)+millisec(1)); //construct a new time by subtracting some times ptime t2 = t1 - hours(5)- minutes(4)- seconds(2)- millisec(1); //construct a duration by taking the difference between times time_duration td = t2 - t1; std::cout << to_simple_string(t2) << " - " << to_simple_string(t1) << " = " << to_simple_string(td) << std::endl; return 0; } ]]>