Timezone stuff and System V Verification Suite

Arthur David Olson ado
Tue Jul 14 17:53:06 UTC 1987

Here are excerpts from two notes from Mike Wescott
(wescott at ncrcae.Columbia.NCR.COM); I'd appreciate comments on the changes Mike
suggests.  (Lines preceded by "> " in the second note are Mike quoting me.)


Date: Thu, 9 Jul 87 15:29:36 pdt
Message-Id: <8707092229.AA00730 at 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>
	printf("%s\n%s\n", tzname[0], tzname[1]);

and try the following:

TZ=PST8PDT ./xxx

it produces:

and TZ=EST5EDT ./xxx produces


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 at 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 at 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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