On 11/28/10 02:17, Ray Dillinger wrote: > Which "second" is preferable depends on the application.
Excellent summary of the situation, Ray! As I see it, given that applications will want both seconds, the choice here is really whether to provide both (look at the POSIX realtime clocks API, which gives you separate "monotonic", "real time", "cpu time", etc clocks), or to just provide one more "primitive" clock and let the second clock be defined at a higher level. Personally, I think "SI seconds elapsed since some epoch" is more fundamental - that's useful even on tiny microcontrollers with no real-time clock. That epoch might be system or process startup in such cases. Time including leap seconds is, in my opinion, less fundamental as it's all about human-chosen approximations to the motions of some planet or other, to make it easier for them to decide when to sleep... And as for the units: we can't measure the time exactly, so surely inexact is quite appropriate? And even if we do develop an exact clock, we have rationals to express that... So make the unit seconds! ABS -- Alaric Snell-Pym http://www.snell-pym.org.uk/alaric/ _______________________________________________ r6rs-discuss mailing list [email protected] http://lists.r6rs.org/cgi-bin/mailman/listinfo/r6rs-discuss
