Joe Gwinn wrote:
"Broken-down time" in POSIX resembles UTC, but as leap seconds are not applied,is not in fact UTC. The fundamental problem with POSIX here is that the functions specified for conversion between POSIX Time and broken-down time fail if leap seconds are involved, in particular there are time values in one form that cannot be expressed in the other form. True UTC, as defined in ITU TR 460-4, does not share this problem, so posix is broken here.
The severely practical problem is that clocks on POSIX systems are typically set from UTC (either directly, or via NTP) and are then expected to tick TAI time units thereafter. This produces a whole set of scales each 1 sec off from its neighbor. Even systems which adjust their local clocks to take leap seconds into account typically do so only for a range of leap seconds, roughly, those which occurred before the machine was installed. -- There is / one art || John Cowan <jcowan@reutershealth.com> no more / no less || http://www.reutershealth.com to do / all things || http://www.ccil.org/~cowan with art- / lessness \\ -- Piet Hein