Sept. 21, 2016
1:31 a.m.
Paul Eggert wrote:
Deborah Goldsmith wrote:
Is the intent that successive versions of the tzfile format will be compatible with older implementations of localtime.c, date.c, etc.?
Yes, that sort of backward-compatibility has been a goal.
Case in point: the files now contain tables of 64-bit information which allow 64-bit code to work correctly on dates past 2038-01-18. But the files *also* contain redundant, parallel tables of 32-bit information usable by 32-bit code. (Naturally 32-bit code will have problems in 2038, but there's no way around that.) The format is such that a version-1 (32-bit) reader will cleanly read the 32-bit data and cleanly ignore the 64-bit extended data that it has no knowledge of.