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July 1987

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2 discussions

Re: Timezone stuff and System V Verification Suite
by seismo!scubed!ncr-sd!ncrcae!sauron!wescott 24 Jul '87

24 Jul '87

> I think the "right" fix is to remove the "Link" lines from the > "northamerica" file (which provides the EST5EDT aliases) and > put them in the "systemv" file, where the data should be an > accurate System V emulation. > ... > Or perhaps the "blessed" 2 zone names should be marked in the > data file to avoid surprises. That's an idea. We (NCR) are really looking for the best of both worlds. We like the flexibility of the PD ctime but need to pass the SVVS as well as provide compatibility for existing customers. The only problem has been that of tzname(). > Both the Sys V and BSD standard timezone name stuff is trash, > it all needs to be discarded completely. And the matter gets worse with SysVr3v1 (from ctime(3c) man page): [start of quote] tzset() uses the contents of the environment variable TZ to override the value of the different external variables. The syntax of TZ can be described as follows: TZ -> zone | zone signed_time | zone signed_time zone | zone signed_time zone dst zone -> letter letter letter signed_time -> sign time | time time -> hour | hour : minute | hour : minute : second dst -> signed_time | signed_time ; dst_date , dst_date | ; dst_date , dst_date dst_date -> julian | julian / time [...] For example, the setting for New Jersey in 1986 could be "EST5EDT4;117/2:00:00,299/2:00:00" [...] A southern hemisphere setting such as the Cook Islands could be "KDT9:30KST10:00;64/5:00,303/20:00" [end of quote] There is a new extern long to go along with timezone called "altzone" which holds the value of the daylight saving time "timezone" offset. The SVID, however, does not reflect this "improvement" nor apparently will the SVVS. The "Future Directions" section of the SVID does mention the fractional hours/sign component in the middle of the TZ variable. The ctime(3c) man page also describes two new routines that allow user control of the formatting of the string as well as using non-english names (under the control of the env. var. LANGUAGE). -Mike Wescott wescott(a)ncrcae.Columbia.NCR.COM

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Timezone stuff and System V Verification Suite
by ado 19 Jul '87

19 Jul '87

Here are excerpts from two notes from Mike Wescott (wescott(a)ncrcae.Columbia.NCR.COM) I'd appreciate comments on the changes Mike suggests. (Lines preceded by "> " in the second note are Mike quoting me.) --ado Date: Thu, 9 Jul 87 15:29:36 pdt Message-Id: <8707092229.AA00730(a)SCUBED.ARPA> Subject: Re: v08i085: Public Domain localtime We have uncovered a problem with the PD ctime with respect to the System V Verification Suite and SVID compatibility. The problem is with tzset(). Try the little program, xxx.c: #include <time.h> main() { tzset(); printf("%s\n%s\n", tzname[0], tzname[1]); } and try the following: TZ=PST8PDT ./xxx it produces: PST PWT and TZ=EST5EDT ./xxx produces EST EWT The problem is that tzname[1] become the (obsolete) EWT. The fix, I believe, would be to use the most recently used abbreviations to the value of time(0). Diff for such a fix follows and passes SVVS. -Mike Wescott wescott(a)ncrcae.Columbia.NCR.COM *** localtime.c.or Thu Jul 9 09:57:27 1987 --- localtime.c Thu Jul 9 14:31:38 1987 *************** *** 90,95 **** --- 90,96 ---- { register int i; register int fid; + time_t now; if (name == 0 && (name = TZDEFAULT) == 0) return -1; *************** *** 182,191 **** timezone = -s.ttis[0].tt_gmtoff; daylight = 0; #endif /* USG_COMPAT */ ! for (i = 1; i < s.typecnt; ++i) { register struct ttinfo * ttisp; ! ! ttisp = &s.ttis[i]; if (ttisp->tt_isdst) { tzname[1] = &s.chars[ttisp->tt_abbrind]; #ifdef USG_COMPAT --- 183,194 ---- timezone = -s.ttis[0].tt_gmtoff; daylight = 0; #endif /* USG_COMPAT */ ! now = time(0); ! for (i = 1; i < s.timecnt; ++i) { register struct ttinfo * ttisp; ! if (now < s.ats[i]) ! break; ! ttisp = &s.ttis[s.types[i]]; if (ttisp->tt_isdst) { tzname[1] = &s.chars[ttisp->tt_abbrind]; #ifdef USG_COMPAT ------------------------------------------------------------------------------- Date: Tue, 14 Jul 87 07:22:19 pdt Message-Id: <8707141422.AA27049(a)SCUBED.ARPA> Subject: Re: v08i085: Public Domain localtime > Many thanks for the note on the problem with SVVS. > Would it be all right with you if I passed the note on to other interested > folks? No problem, I sent it to you with that in mind. The code could probably be made a little more efficient but it shouldn't have to run too often. > Also--the time zone files described in the "systemv" file were designed to > provide System V compatibility. It looks as if you're in a position to check > on whether they actually do; if you could, I'd appreciate it. We ran SVVS (SysVr2 not r3 yet) and the only thing it complained about was the problem with the tzset() function. We are compiling with USG, USG_COMPAT, and STD_INSPIRED defined. I'll check the "systemv" file but it doesn't seem to be problem as far as SVVS goes.

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