- tz - lists.iana.org

Unix time_t hits 1.5Gs early Friday UTC
by Brian Inglis July 14, 2017

July 14, 2017

Unix time_t will hit 1 500 000 000 at 2017 Jul 14 Fri 02:40:00+0000 which is Thursday evening in North America: $ for city in Vancouver Edmonton Regina Winnipeg Toronto Halifax St_Johns; do TZ=America/$city date -d@1500000000 +%c\ %Z; done 2017 Jul 13 Thu 19:40:00 PDT 2017 Jul 13 Thu 20:40:00 MDT 2017 Jul 13 Thu 20:40:00 CST 2017 Jul 13 Thu 21:40:00 CDT 2017 Jul 13 Thu 22:40:00 EDT 2017 Jul 13 Thu 23:40:00 ADT 2017 Jul 14 Fri 00:10:00 NDT and on some other time scales, which may not be aligned to UTC: $ gpstime.sh @1500000000 2017 Jul 14 Fri 02:40:00+0000 JD 2457948.611111 MJD 57948.111111 ToD 9599 NTP 3708988800 Unix 1500000000 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 1957 Cy 1 Wn 933 Wa 165 ToW 441618 DoW 5 ToD 9618 As usual there will be some Europeans staying up late to celebrate and party. Unix time won't hit 1.5Gis until: $ gpstime.sh @`bc <<< 2^30*3/2` 2021 Jan 14 Thu 08:25:36+0000 JD 2459228.851111 MJD 59228.351111 ToD 30336 NTP 3819601536 Unix 1610612736 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 2140 Cy 2 Wn 92 Wa 92 ToW 375954 DoW 4 ToD 30354 and it will be a while before it hits 2Gs: $ gpstime.sh @2000000000 2033 May 18 Wed 03:33:20+0000 JD 2463735.648148 MJD 63735.148148 ToD 12799 NTP 4208988800 Unix 2000000000 TAI-UTC 37 TAI-GPS 19 GPS-UTC 18 GPS We 2784 Cy 2 Wn 736 Wa 224 ToW 272018 DoW 3 ToD 12818 -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada

3 2

Use GST abbreviation for Asia/Dubai, Asia/Muscat
by Mohamed Akram July 14, 2017

July 14, 2017

I noticed Asia/Dubai and Asia/Muscat currently use +04, but there is an existing abbreviation (GST - Gulf Standard Time).

3 3

Etc/GMT timezone offsets are inverted
by Pedro A. López-Valencia July 11, 2017

July 11, 2017

I just noticed that all GMT+- timezones are inverted so that GMT+5 is really GMT-5. This applies to all GMT-offset timezone definitions. -- https://about.me/palopezv

2 1

IERS Bulletin C54
by Michael Deckers July 11, 2017

July 11, 2017

The IERS has issued Bulletin C54 which assures that no leap second will occur near 2018-01-01. Interestingly, the issue date 2017-07-06 in the txt version at [https://datacenter.iers.org/eop/-/somos/5Rgv/getTX/16/bulletinc-054.txt] differs from the issue date 2017-07-09 in the xml version at [https://datacenter.iers.org/eop/-/somos/5Rgv/latestXL/16/bulletinc-054.txt/…] Michael Deckers. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

5 7

backzone/Europe/Guernsey
by Michael Deckers July 10, 2017

July 10, 2017

For the connoisseurs of olde time stamps: The "LMT location" for backzone/Europe/Guernsey is given as "49.27N -2.33E" -- seemingly in degrees and decimal fractions of degrees. But the point ( +49.27°, -2.33° ) = ( +49°16′12″, -002°19′48″ ) is in open waters about 15 km south of Guernsey and east of Sark in the Channel. The point ( +49°27′, -002°33′ ), however, is in St Peter Port on the island, so that arc minutes and not hundredths of degrees must be meant. This also agrees with zone.tab. Hence: -# LMT Location - 49.27N -2.33E - St.Peter Port +# LMT Location - 49°27′N -2°33′E - St.Peter Port -Zone Europe/Guernsey -0:09:19 - LMT 1913 Jun 18 +Zone Europe/Guernsey -0:10:12 - LMT 1913 Jun 18 Michael Deckers. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

3 3

Re: [tz] TZ & AIX
by Paul Eggert July 8, 2017

July 8, 2017

Jorge Fábregas wrote: > https://www.ibm.com/developerworks/aix/library/au-aix-olson-time-zone/index… Thanks for the heads-up. I installed the attached.

2 1

Orillia's 1912 DST pops up again in Toronto Star
by Paul Eggert July 8, 2017

July 8, 2017

Today's Toronto Star reports on the two-week daylight saving time interlude in Orillia, Ontario. Today's article doesn't mention the same newspaper's 1997-10-14 article on the same topic, and it's not clear what's new this time around. Still, the story is amusingly told. Proposed patch attached.

1 0

DST in the (odd) news
by Arthur David Olson July 7, 2017

July 7, 2017

"Alarm clock removed from family's home after 14 years of daily beeping" "Over the years, it beeped at 6.50pm or 7.50pm each day, depending on whether Daylight [Saving] Time was in place." https://www.theguardian.com/us-news/2017/jul/07/alarm-clock-wall-pennsylvan… @dashdashado

1 0

[PROPOSED] Avoid zic problems with errno == EOVERFLOW
by Paul Eggert June 26, 2017

June 26, 2017

Although this patch does not fix any bugs, it makes zic’s ‘stat’ calls less likely to fail unnecessarily with errno == EOVERFLOW, and this should be a bit faster in some cases. Problem reported by Nick Alcock in: https://sourceware.org/ml/libc-alpha/2017-06/msg01264.html * private.h (_FILE_OFFSET_BITS, _LARGE_FILES) (_DARWIN_USE_64_BIT_INODE): New macros. --- private.h | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/private.h b/private.h index f5e39b5..2e8415e 100644 --- a/private.h +++ b/private.h @@ -102,6 +102,16 @@ /* Enable strtoimax on pre-C99 Solaris 11. */ #define __EXTENSIONS__ 1 +/* To avoid having 'stat' fail unnecessarily with errno == EOVERFLOW, + enable large files on GNUish systems ... */ +#ifndef _FILE_OFFSET_BITS +# define _FILE_OFFSET_BITS 64 +#endif +/* ... and on AIX ... */ +#define _LARGE_FILES 1 +/* ... and enable large inode numbers on Mac OS X 10.5 and later. */ +#define _DARWIN_USE_64_BIT_INODE 1 + /* ** Nested includes */ -- 2.9.4

1 0

[PROPOSED] Port to GCC 4.8.4
by Paul Eggert June 16, 2017

June 16, 2017

Problem reported by Stan Shebs and Joseph Myers in: https://sourceware.org/ml/libc-alpha/2017-06/msg00741.html * NEWS, Makefile: Document this. * private.h (HAVE_GENERIC): New macro, so that we do not use _Generic with GCC 4.8. (TIME_T_MIN_NO_PADDING, TIME_T_MAX_NO_PADDING): New macros. (TIME_T_MIN, TIME_T_MAX): Rename from time_t_min and time_t_max, and turn them into macros so that problems are less likely to occur for subset uses like glibc where these macros are never expanded. All uses changed. Use new macros to work around GCC 4.8 bug. --- Makefile | 1 + NEWS | 3 +++ date.c | 2 +- localtime.c | 26 +++++++++++++------------- private.h | 60 ++++++++++++++++++++++++++++++++++++++++-------------------- 5 files changed, 58 insertions(+), 34 deletions(-) diff --git a/Makefile b/Makefile index 2b31f3f..347ece7 100644 --- a/Makefile +++ b/Makefile @@ -142,6 +142,7 @@ LDLIBS= # -DHAVE_DECL_ASCTIME_R=0 if <time.h> does not declare asctime_r # -DHAVE_DECL_ENVIRON if <unistd.h> declares 'environ' # -DHAVE_DIRECT_H if mkdir needs <direct.h> (MS-Windows) +# -DHAVE_GENERIC=0 if _Generic does not work # -DHAVE_GETTEXT if 'gettext' works (e.g., GNU/Linux, FreeBSD, Solaris) # -DHAVE_INCOMPATIBLE_CTIME_R if your system's time.h declares # ctime_r and asctime_r incompatibly with the POSIX standard diff --git a/NEWS b/NEWS index ca4fd8e..cfdd620 100644 --- a/NEWS +++ b/NEWS @@ -94,6 +94,9 @@ Unreleased, experimental changes zdump.c no longer assumes snprintf. (Reported by Jonathan Leffler.) + Calculation of time_t extrema works around a bug in GCC 4.8.4 + (Reported by Stan Shebs and Joseph Myers.) + Several minor changes have been made to the code to make it a bit easier to port to MS-Windows and Solaris. (Thanks to Kees Dekker for reporting the problems.) diff --git a/date.c b/date.c index b29e162..2cc533f 100644 --- a/date.c +++ b/date.c @@ -97,7 +97,7 @@ main(const int argc, char *argv[]) secs = strtoimax (optarg, &endarg, 0); if (*endarg || optarg == endarg) errno = EINVAL; - else if (! (time_t_min <= secs && secs <= time_t_max)) + else if (! (TIME_T_MIN <= secs && secs <= TIME_T_MAX)) errno = ERANGE; if (errno) { perror(optarg); diff --git a/localtime.c b/localtime.c index 8c944f3..2e1d621 100644 --- a/localtime.c +++ b/localtime.c @@ -464,17 +464,17 @@ tzloadbody(char const *name, struct state *sp, bool doextend, sp->charcnt = charcnt; /* Read transitions, discarding those out of time_t range. - But pretend the last transition before time_t_min - occurred at time_t_min. */ + But pretend the last transition before TIME_T_MIN + occurred at TIME_T_MIN. */ timecnt = 0; for (i = 0; i < sp->timecnt; ++i) { int_fast64_t at = stored == 4 ? detzcode(p) : detzcode64(p); - sp->types[i] = at <= time_t_max; + sp->types[i] = at <= TIME_T_MAX; if (sp->types[i]) { time_t attime - = ((TYPE_SIGNED(time_t) ? at < time_t_min : at < 0) - ? time_t_min : at); + = ((TYPE_SIGNED(time_t) ? at < TIME_T_MIN : at < 0) + ? TIME_T_MIN : at); if (timecnt && attime <= sp->ats[timecnt - 1]) { if (attime < sp->ats[timecnt - 1]) return EINVAL; @@ -524,7 +524,7 @@ tzloadbody(char const *name, struct state *sp, bool doextend, /* Leap seconds cannot occur before the Epoch. */ if (tr < 0) return EINVAL; - if (tr <= time_t_max) { + if (tr <= TIME_T_MAX) { /* Leap seconds cannot occur more than once per UTC month, and UTC months are at least 28 days long (minus 1 second for a negative leap second). Each leap second's @@ -1795,12 +1795,12 @@ increment_overflow_time(time_t *tp, int_fast32_t j) { /* ** This is like - ** 'if (! (time_t_min <= *tp + j && *tp + j <= time_t_max)) ...', + ** 'if (! (TIME_T_MIN <= *tp + j && *tp + j <= TIME_T_MAX)) ...', ** except that it does the right thing even if *tp + j would overflow. */ if (! (j < 0 - ? (TYPE_SIGNED(time_t) ? time_t_min - j <= *tp : -1 - j < *tp) - : *tp <= time_t_max - j)) + ? (TYPE_SIGNED(time_t) ? TIME_T_MIN - j <= *tp : -1 - j < *tp) + : *tp <= TIME_T_MAX - j)) return true; *tp += j; return false; @@ -1936,8 +1936,8 @@ time2sub(struct tm *const tmp, /* ** Do a binary search (this works whatever time_t's type is). */ - lo = time_t_min; - hi = time_t_max; + lo = TIME_T_MIN; + hi = TIME_T_MAX; for ( ; ; ) { t = lo / 2 + hi / 2; if (t < lo) @@ -1954,12 +1954,12 @@ time2sub(struct tm *const tmp, } else dir = tmcomp(&mytm, &yourtm); if (dir != 0) { if (t == lo) { - if (t == time_t_max) + if (t == TIME_T_MAX) return WRONG; ++t; ++lo; } else if (t == hi) { - if (t == time_t_min) + if (t == TIME_T_MIN) return WRONG; --t; --hi; diff --git a/private.h b/private.h index 2b07251..f5e39b5 100644 --- a/private.h +++ b/private.h @@ -27,6 +27,21 @@ #define HAVE_DECL_ASCTIME_R 1 #endif +#if !defined HAVE_GENERIC && defined __has_extension +# if __has_extension(c_generic_selections) +# define HAVE_GENERIC 1 +# else +# define HAVE_GENERIC 0 +# endif +#endif +/* _Generic is buggy in pre-4.9 GCC. */ +#if !defined HAVE_GENERIC && defined __GNUC__ +# define HAVE_GENERIC (4 < __GNUC__ + (9 <= __GNUC_MINOR__)) +#endif +#ifndef HAVE_GENERIC +# define HAVE_GENERIC (201112 <= __STDC_VERSION__) +#endif + #ifndef HAVE_GETTEXT #define HAVE_GETTEXT 0 #endif /* !defined HAVE_GETTEXT */ @@ -561,27 +576,32 @@ time_t time2posix_z(timezone_t, time_t) ATTRIBUTE_PURE; #define MINVAL(t, b) \ ((t) (TYPE_SIGNED(t) ? - TWOS_COMPLEMENT(t) - MAXVAL(t, b) : 0)) -/* The minimum and maximum finite time values. This implementation - assumes no padding if time_t is signed and either the compiler is - pre-C11 or time_t is not one of the standard signed integer types. */ -#if 201112 <= __STDC_VERSION__ -static time_t const time_t_min - = (TYPE_SIGNED(time_t) - ? _Generic((time_t) 0, - signed char: SCHAR_MIN, short: SHRT_MIN, - int: INT_MIN, long: LONG_MIN, long long: LLONG_MIN, - default: MINVAL(time_t, TYPE_BIT(time_t))) - : 0); -static time_t const time_t_max - = (TYPE_SIGNED(time_t) - ? _Generic((time_t) 0, - signed char: SCHAR_MAX, short: SHRT_MAX, - int: INT_MAX, long: LONG_MAX, long long: LLONG_MAX, - default: MAXVAL(time_t, TYPE_BIT(time_t))) - : -1); +/* The extreme time values, assuming no padding. */ +#define TIME_T_MIN_NO_PADDING MINVAL(time_t, TYPE_BIT(time_t)) +#define TIME_T_MAX_NO_PADDING MAXVAL(time_t, TYPE_BIT(time_t)) + +/* The extreme time values. These are macros, not constants, so that + any portability problem occur only when compiling .c files that use + the macros, which is safer for applications that need only zdump and zic. + This implementation assumes no padding if time_t is signed and + either the compiler lacks support for _Generic or time_t is not one + of the standard signed integer types. */ +#if HAVE_GENERIC +# define TIME_T_MIN \ + _Generic((time_t) 0, \ + signed char: SCHAR_MIN, short: SHRT_MIN, \ + int: INT_MIN, long: LONG_MIN, long long: LLONG_MIN, \ + default: TIME_T_MIN_NO_PADDING) +# define TIME_T_MAX \ + (TYPE_SIGNED(time_t) \ + ? _Generic((time_t) 0, \ + signed char: SCHAR_MAX, short: SHRT_MAX, \ + int: INT_MAX, long: LONG_MAX, long long: LLONG_MAX, \ + default: TIME_T_MAX_NO_PADDING) \ + : (time_t) -1) #else -static time_t const time_t_min = MINVAL(time_t, TYPE_BIT(time_t)); -static time_t const time_t_max = MAXVAL(time_t, TYPE_BIT(time_t)); +# define TIME_T_MIN TIME_T_MIN_NO_PADDING +# define TIME_T_MAX TIME_T_MAX_NO_PADDING #endif /* -- 2.9.4

1 0