Daylight Savings Time, Leap Years, ctime, and date

[Guy Harris]

 > >   2) Does anyone know if the new versions are less naive about determining
 > >      leap years? It seems the current routines only use the "year % 4 ==0"
 > >      rule.
 > 
 >Fixed by POSIX as I recall.  (POSIX == IEEE 1003.1 standard in this case).

Nope.  POSIX just refers to ANSI C for the descriptions of "localtime"
and "mktime", and the (d)(p)ANS doesn't say anything about how those
routines should decide what a leap year is.  It's a
quality-of-implementation issue.