In PCTS, "ambiguous" is referring to the time periods at, and 59:59 minutes after the start of daylight savings, where the time given is as if there were no transition to daylight savings 59:59 minutes before, and at the end of daylight savings, where the time given is as if there were no transition from daylight savings and tm_isdst = -1, assuming the difference between standard vs. daylight is 60:00 minutes. I've run tests on SVR4v3 and HP-UX C.09.01 systems and found their mktime() maps 02:MM:SS/DST-UNKNOWN to 01:MM:SS/DST-OFF I think I prefer 02:MM:SS/DST-UNKNOWN to 03:MM:SS/DST-ON but either mapping is acceptable to PCTS. ------- Forwarded Message Return-Path: bww+@transarc.com Received: from sparc51.transarc.com (sparc51.transarc.com, [192.55.207.51]) by transarc.com (5.54/3.15) id <AA06638> for grant@osf.org; Wed, 23 Mar 94 14:51:15 EST Received: by sparc51.transarc.com with BradMail(MH 6.8); Wed, 23 Mar 1994 14:51:06 -0500 (EST) To: Grant Sullivan <grant@osf.org> Cc: Arthur David Olson <ado@elsie.nci.nih.gov> Subject: Re: mktime() failures under PCTS testing In-Reply-To: Your message of Wed, 23 Mar 1994 13:37:01 -0500 Date: Wed, 23 Mar 1994 14:51:05 -0500 (EST) Message-Id: <16001.764452265@sparc51.transarc.com> From: Bradley White <bww+@transarc.com>

mktime() is failing only those PCTS tests which test "ambiguous" transitions from standard to daylight time. mktime() passes all the tests for "ambiguous" transitions from daylight to standard time, however.

The first and second senses of the word "ambiguous" should be distinguished. The daylight->standard transition period does indeed include wall-clock times that each correspond to two distinct time_t's. However, the standard->daylight transition period renders wall-clock times that simply do not exist. And now my opinion: I am all for mktime() failing for *all* non-existent times-of-day, but, given that we do `isdst' correction, and map the non-existent times of ... 02:MM:SS/DST-OFF to 03:MM:SS/DST-ON and 02:MM:SS/DST-ON to 01:MM:SS/DST-OFF ..., it seems that we should also map 02:MM:SS/DST-UNKNOWN to one of those. Bradley PS: I won't mention that the test suite assumes too much about time_t's :-). ------- End of Forwarded Message