A NOTE has been added to this issue. ====================================================================== https://austingroupbugs.net/view.php?id=1788 ====================================================================== Reported By: Guy Harris Assigned To: ====================================================================== Project: 1003.1(2016/18)/Issue7+TC2 Issue ID: 1788 Category: Base Definitions and Headers Type: Clarification Requested Severity: Comment Priority: normal Status: New Name: Guy Harris Organization: User Reference: Section: N/A Page Number: N/A Line Number: N/A Interp Status: --- Final Accepted Text: ====================================================================== Date Submitted: 2023-11-18 00:16 UTC Last Modified: 2023-11-22 19:40 UTC ====================================================================== Summary: The meaning of "Daylight Saving Time" should be clarified ====================================================================== Relationships ID Summary ---------------------------------------------------------------------- related to 0001253 clarify that "alternative time&quo... ======================================================================
---------------------------------------------------------------------- (0006583) Guy Harris (reporter) - 2023-11-22 19:40 https://austingroupbugs.net/view.php?id=1788#c6583 ---------------------------------------------------------------------- One use for tm_isdst as an output from localtime() would be to choose which element of tzname[] is the right time zone abbreviation for the time that was converted. However, neither the current standard nor Draft 3 appears to state, specifically, that tzname[tm->tm_isdst] is the right time zone name; that's merely suggested by the contents of the sections describing tzname[], time.h, and the TZ environment variable. I think that's the intention of the people at AT&T who originally provided it, but that doesn't suffice for a specification. In systems that support tm_zone as a member of struct tm, using that is preferable; perhaps the 202x standard should not only require tm_zone and tm_gmtoff, but deprecate tm_isdst, tzname[], timezone, and daylight in favor of those fields. Those fields don't let you find out whether "Daylight Saving Time is in effect", but, given that "Daylight Saving Time" is not defined by the standard, it's not clear that finding out whether Daylight Saving Time is in effect provides any information that's useful if you already know the UTC offset and time zone abbreviation name. Issue History Date Modified Username Field Change ====================================================================== 2023-11-18 00:16 Guy Harris New Issue 2023-11-18 00:16 Guy Harris Name => Guy Harris 2023-11-18 00:16 Guy Harris Section => N/A 2023-11-18 00:16 Guy Harris Page Number => N/A 2023-11-18 00:16 Guy Harris Line Number => N/A 2023-11-20 01:03 Don Cragun Note Added: 0006573 2023-11-20 01:04 Don Cragun Relationship added related to 0001253 2023-11-20 17:10 kre Note Added: 0006576 2023-11-22 19:40 Guy Harris Note Added: 0006583 ======================================================================
