On Sat, 28 Sep 2002, Jarkko Hietaniemi wrote:
> I think in general UNIX-like kernels (thankfully) don't have any idea > of timezones or DSTs, they simply operate in UTC. All complex stuff > (like what should be done with a US user currently sitting in their UK > office accessing a database in Japan using an application in Australia) > is left to the upper layers to worry about. It would appear that VMS and Mac OS have this property too. On the matter of DST and geography under Mac OS I did manage to find a web page at Apple: http://developer.apple.com/techpubs/macosx/Carbon/text/DateTimeUtilities/Date_Time_an_nt_Utilities/index.html That asserts that: "You can use the routines provided by the Date, Time, and Measurement Utilities to", ... "get and set the geographic location and time-zone information", etc. and in Mac OS 9 the relevant headers are apparently DateTimeUtils.h and UTCUtils.h. I have yet to find a clear example of the geographic location or TZ determination. However, it would seem that if I can determine the current localtime(), the current UTC time, the current dst setting, and if I can accurately (meaning take DST transition into account) determine the localtime vs. UTC time difference for some other date then I should be able to determine the dst setting for that other date by calculating today's UTC offset and comparing the quantities. Peter Prymmer
