Jonathan Leffler wrote:
AFAICT, the logic associated with sp->goback and sp->goahead in tzload() and in localsub() in localtime.c could only ever be used if there were at least 800 time change entries, enough for two per year for a 400 year cycle. And, empirically, there are no time zone definitions in the current (2007k) data set that get anywhere close to this.
However, this code can't have been put in there for no reason whatsoever, so I'd like to understand what was the intention - if anybody can remember.
I'm not positive, but I *think* that it was an effort to support solar time in the Arab countries; solar time was approximated by making several hundred time zone changes *per year*. The legacy 'solar87,' 'solar88' and 'solar89' files in tzdata show what was being tried. -- 7e de ke9tv/2, Kevin