It seems it might be more useful if the interface of the date-time library were changed to either use a single precision (milliseconds or microseconds) or allow the precision to be specified by the user as a template parameter (i.e. the user could specify seconds, milliseconds, microseconds, or nanoseconds). The actual precision of the current time clock would of course depend on the platform-specific facilities available for accessing the system time. Then the primary representation of a time duration would be the total number of seconds/milliseconds/microseconds/nanoseconds and the primary representation of a time point could be a time duration since a fixed epoch in a fixed time zone, i.e. 1970-01-01 00:00:00.0000 UTC. This would allow convenient separation of the calendar handling from the time representation, and the time representation could be used without the calendar handling. -- Jeremy Maitin-Shepard