On Thu, 6 Jun 2013 23:48:46 -0700, Ed Jaffe wrote: > >DS9TIME DS XL6 Number of microseconds since >* midnight, local time, ... > Did I fail to read this correctly previously? Now that I look more carefully, it seems to be saying that the field stores a counter that is reset to 0 each midnight, local time, and counts uniformly until the next midnight. So on most days, it will reset after 24 hours worth of microseconds. On the day of the Fall Daylight Saving Time boundary, it will reset only after 25 hours' worth of microseconds; on the day of the Spring Daylight Saving Time boundary, it will reset after only 23 hours' worth of microseconds. No ambiguity, but tricky to convert to local time. And the best way for allocation to compute the needed value is to save the (E)TOD value each midnight and subtract from the (E)TOD value at the time of allocation.
Are there locales where the Daylight Saving Time boundary occurs at midnight, or spans midnight so there might be two midnights, an hour apart? Or none, in the Spring? Leap seconds? If one is concerned with microsecond precision, one needs to be concerned with how leap seconds are treated. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
