Nov. 11, 2016
2:46 a.m.
On 11/10/2016 05:12 PM, Guy Harris wrote:
Emacs wants a consistent and complete snapshot of the current rule set for all times from now into the indefinite future. To what use does it put that snapshot?
It's the calendar code contributed by E.M. Reingold. As I recall, Emacs can tell you what day and time DST is scheduled to begin in the year 2039, even on a platform with signed 32-bit time_t so that localtime/mktime do not work that far into the future. The calendar code uses Y-M-D arithmetic to work around the Y2038 problem. (Lots of hairy stuff there, written back when you couldn't reasonably tell people to get 64-bit machines but people still wanted to calculate the date of Easter 1066 in the Julian calendar, that sort of thing.)