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Fwd: Bulletin C number 69
by Tim Parenti Jan. 7, 2025

Jan. 7, 2025

No leap second 2025-06-30, per below. See attached patch. -- Tim Parenti ---------- Forwarded message --------- From: IERS EOP Product Center <iers.eoppc(a)obspm.fr> Date: Tue, 7 Jan 2025 at 05:00 Subject: Bulletin C number 69 To: <bulc.iers(a)obspm.fr> INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE DE L'IERS OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : +33 1 40 51 23 35 e-mail : services.iers(a)obspm.fr http://hpiers.obspm.fr/eop-pc Paris, 06 January 2025 Bulletin C 69 To authorities responsible for the measurement and distribution of time INFORMATION ON UTC - TAI NO leap second will be introduced at the end of June 2025. The difference between Coordinated Universal Time UTC and the International Atomic Time TAI is : from 2017 January 1, 0h UTC, until further notice : UTC-TAI = -37 s Leap seconds can be introduced in UTC at the end of the months of December or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every six months, either to announce a time step in UTC, or to confirm that there will be no time step at the next possible date. Christian BIZOUARD Director Earth Orientation Center of IERS Observatoire de Paris, France

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Y2K on the radio
by Arthur Olson Dec. 31, 2024

Dec. 31, 2024

With a New Year looming, an NPR Y2K review. (Alas, no mention of T2G in 2038.) @dashdashado https://www.npr.org/2024/12/28/nx-s1-5116271/y2k-year-2000-preparations

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[PROPOSED] For timestamps compare to HEAD not to index
by Paul Eggert Dec. 30, 2024

Dec. 30, 2024

Problem reported by Bruno Haible in: https://lists.gnu.org/r/bug-gnulib/2024-12/msg00245.html * Makefile (set-timestamps.out): When comparing working file to repository, Use ‘git diff HEAD’ instead of plain ‘git diff’. --- Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/Makefile b/Makefile index ffdbfe3b..e00b0f32 100644 --- a/Makefile +++ b/Makefile @@ -1104,7 +1104,7 @@ set-timestamps.out: $(EIGHT_YARDS) touch -md @1 test.out; then \ rm -f test.out && \ for file in $$files; do \ - if git diff --quiet $$file; then \ + if git diff --quiet HEAD $$file; then \ time=$$(TZ=UTC0 git log -1 \ --format='tformat:%cd' \ --date='format:%Y-%m-%dT%H:%M:%SZ' \ -- 2.47.1

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Deprecate two digit year formats %D %g %y
by Brian Inglis Dec. 29, 2024

Dec. 29, 2024

Hi folks, [Spurred by NPR Y2K review article.] Could we please all make a New Year's resolution to stop people from reviving two digit year formats that are starting to reappear, making it impossible to figure out some intended dates, and officially deprecate all two digit year formats %D %g %y across all standards, and tools default to options like gcc's and clang's -Wformat-y2k (included in -Wformat=2) and clang's -Wdeprecate. -- Take care. Thanks, Brian Inglis Calgary, Alberta, Canada La perfection est atteinte Perfection is achieved non pas lorsqu'il n'y a plus rien à ajouter not when there is no more to add mais lorsqu'il n'y a plus rien à retirer but when there is no more to cut -- Antoine de Saint-Exupéry

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Request for inclusion of Trivandrum in the IANA Time Zone Database
by Anish shivaraj Dec. 28, 2024

Dec. 28, 2024

Dear tzdata Maintainers, I am writing to propose the inclusion of Trivandrum (Thiruvananthapuram) as a new entry in the IANA Time Zone Database (tzdata). As the capital city of Kerala, Trivandrum holds significant historical, economic, and technological importance, and its addition to the database would reflect its growing prominence. Justification for Inclusion Population and Prominence With a population exceeding 1 million, Trivandrum is well above the 300,000 threshold for inclusion.The city serves as a political, cultural, and economic hub in southern India. Economic Growth and Commercial Significance Vizhinjam International Seaport: Trivandrum is home to India’s first transshipment port, the Vizhinjam International Seaport, which is expected to position the city as a major player in global shipping and logistics. Emerging Commercial Hub: The growth of the Vizhinjam port has already made Trivandrum an important center for commerce, attractingsignificant investments and fostering local economic development. Technological and Space Research Importance India’s First IT Park: Technopark in Trivandrum is the country’s first and one of the largest IT parks, contributing greatly to India’s IT industry. Space Research and Education: The city houses the Vikram Sarabhai Space Centre (VSSC), a key institution for India’s space exploration efforts. Trivandrum also hosts the Indian Institute of Space Science and Technology (IIST) and the Kerala Space Park, making it a critical hub for space research and innovation. Eligibility Based on Time Zone Criteria Unique Timekeeping History: Trivandrum once had its own local mean time before the adoption of Indian Standard Time (IST), making this distinction relevant for its case. Representative Need: As an emerging commercial, technological,and research center, a separate time zone entry would provide better representation for the region’s users and applications. Alignment with tzdata Objectives - Trivandrum meets the criteria of significant population, historical relevance, and global contributions to shipping, IT, and space research, making it a suitable candidate for inclusion. Proposed Time Zone Entry We suggest adding the following entry: Zone Asia/Trivandrum +05:30 - Trivandrum Standard Time Including Trivandrum in the tzdata database would provide better localization and reflect its growing importance. Thank you for considering this request. Should you require further information or clarification, please do not hesitate to reach out. Best regards, Anish Sivarajan

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Re: Iana build failures on Windows
by Paul Eggert Dec. 19, 2024

Dec. 19, 2024

On 2024-12-17 07:53, Manuela Friedrich wrote: > It's worth noticing that I had to add -DHAVE_SYS_STAT_H=0 to the tools.ini > file we use on Windows. Thanks for mentioning that, but unfortunately I don't know why -DHAVE_SYS_STAT_H=0 was needed (I don't use MS-Windows). Some fumbling with Microsoft documentation eventually led me to <https://learn.microsoft.com/en-us/cpp/c-runtime-library/compatibility?view=…> which hints (but does not say) that by default MS-Windows <sys/stat.h> doesn't define the 'stat' function if you use some compilation options. I installed the attached patch to try to work around this portability problem. Does this patch fix things so that -DHAVE_SYS_STAT_H=0 need not be added to tools.ini? If not, what problems do you observe? With the patch, do you see warnings when compiling? Does compiling with -D_CRT_SECURE_NO_WARNINGS cut down on the number of warnings? What's in your tools.ini file for building tzcode?

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Re: Iana build failures on Windows
by Paul Eggert Dec. 17, 2024

Dec. 17, 2024

On 2024-12-15 23:11, Manuela Friedrich wrote: > localtime.c > d:\devsrc\treasure_test\iana\tmp\private.h(872): warning C4005: 'max': > macro redefinition > C:\Program Files (x86)\Windows > Kits\10\include\10.0.16299.0\ucrt\stdlib.h(1300): note: see previous > definition of 'max' > d:\devsrc\treasure_test\iana\tmp\private.h(873): warning C4005: 'min': > macro redefinition > C:\Program Files (x86)\Windows > Kits\10\include\10.0.16299.0\ucrt\stdlib.h(1301): note: see previous > definition of 'min' > localtime.c(418): error C2065: 'utc': undeclared identifier > localtime.c(418): warning C4047: ':': 'const char *' differs in levels of > indirection from 'int' > localtime.c(1449): error C2065: 'utc': undeclared identifier > localtime.c(1449): warning C4047: 'function': 'const char *' differs in > levels of indirection from 'int' > localtime.c(1449): warning C4024: 'strcpy': different types for formal and > actual parameter 2 > NMAKE : U1077: '"C:\Program Files (x86)\Microsoft Visual > Studio\2017\Professional\VC\Tools\MSVC\14.12.25827\bin\HostX64\x64\cl.EXE"' > : return code '0x2' Thanks for reporting these build glitches on MS-Windows. I installed the attached patches; please give them a try, as I don't use that platform.

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Daylight Saving in the news
by Arthur Olson Dec. 15, 2024

Dec. 15, 2024

"Trump vows to end 'very costly' daylight saving time" (While Mexico may not pay for it, Mexico and Canada may follow suit.) https://www.bbc.com/news/articles/cn9gjvgv4neo @dashdashado

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How permanent daylight saving time or permanent standard time would affect the USA
by Jonathan Leffler Dec. 13, 2024

Dec. 13, 2024

Article in the Washington Post about how early or late you would be in the dark if the USA adopted permanent daylight saving time or permanent standard time (compared with now). https://www.washingtonpost.com/nation/interactive/2024/no-daylight-saving-t… With decent interactive graphics. I'm a subscriber; I don't know if there's a paywall in place. -- Jonathan Leffler <jonathan.leffler(a)gmail.com> #include <disclaimer.h> Guardian of DBD::Informix - v2018.1031 - http://dbi.perl.org "Blessed are we who can laugh at ourselves, for we shall never cease to be amused."

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[PROPOSED] Fix asctime.o, strftime.o dependencies
by Paul Eggert Dec. 11, 2024

Dec. 11, 2024

* Makefile (asctime.o): Don’t depend on tzfile.h. (strftime.o): Depend on tzdir.h, as it’s included indirectly via localtime.c if MKTIME_MIGHT_OVERFLOW. --- Makefile | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/Makefile b/Makefile index 2aafdc24..8faab6ff 100644 --- a/Makefile +++ b/Makefile @@ -1355,11 +1355,11 @@ long-long.ck unsigned.ck: $(VERSION_DEPS) zonenames: tzdata.zi @$(AWK) '/^Z/ { print $$2 } /^L/ { print $$3 }' tzdata.zi -asctime.o: private.h tzfile.h +asctime.o: private.h date.o: private.h difftime.o: private.h -localtime.o: private.h tzfile.h tzdir.h -strftime.o: localtime.c private.h tzfile.h +localtime.o: private.h tzdir.h tzfile.h +strftime.o: localtime.c private.h tzdir.h tzfile.h zdump.o: version.h zic.o: private.h tzfile.h tzdir.h version.h -- 2.47.1

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[PROPOSED] Fix to2050.tzs timestamp in distributed tarball
by Paul Eggert Dec. 11, 2024

Dec. 11, 2024

* Makefile (TZS_DEPS): Remove asctime.c and add localtime.c. --- Makefile | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/Makefile b/Makefile index 5473dedd..2aafdc24 100644 --- a/Makefile +++ b/Makefile @@ -615,8 +615,8 @@ TZS_YEAR= 2050 TZS_CUTOFF_FLAG= -c $(TZS_YEAR) TZS= to$(TZS_YEAR).tzs TZS_NEW= to$(TZS_YEAR)new.tzs -TZS_DEPS= $(YDATA) asctime.c localtime.c \ - private.h tzfile.h zdump.c zic.c +TZS_DEPS= $(YDATA) localtime.c private.h \ + strftime.c tzfile.h zdump.c zic.c TZDATA_DIST = $(COMMON) $(DATA) $(MISC) # EIGHT_YARDS is just a yard short of the whole ENCHILADA. EIGHT_YARDS = $(TZDATA_DIST) $(DOCS) $(SOURCES) tzdata.zi -- 2.47.1

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Add ICU's Etc/Unknown Zone to IANA Time Zone Database?
by Justin Grant Dec. 11, 2024

Dec. 11, 2024

Hi TZ friends - Should the time zone identifier "Etc/Unknown" (standardized in Unicode Technical Standard 35 and used by the ICU <https://icu.unicode.org/> library that implements time zone support in all major web browsers, in Java, and in other platforms) be added to the IANA Time Zone Database? Etc/Unknown would behave the same as the existing time zone identifier "Factory". Ideally, Etc/Unknown could be a Zone and Factory could be turned into a Link pointing to Etc/Unknown, because both of them have the meaning of "the time zone of this computer is not known" but Etc/Unknown is more self-describing and is better aligned with modern Zone naming conventions. Here's more context: "Etc/Unknown" is standardized in https://unicode.org/reports/tr35/#Time_Zone_Identifiers. Here's the relevant text from the standard: > There is a special code "unk" for an Unknown or Invalid time zone. > This can be expressed in the tz database style ID "Etc/Unknown", > although it is not defined in the tz database. Following this standard, Etc/Unknown is returned by ICU <https://icu.unicode.org/> when the time zone of a computer cannot be determined. Here's an example of an ICU method that can return Etc/Unknown: icu::TimeZone::detectHostTimeZone() <https://unicode-org.github.io/icu-docs/apidoc/dev/icu4c/classicu_1_1TimeZon…> . The fact that Etc/Unknown looks like an IANA identifier but is not actually in TZDB has been a long-running source of problems. Most recently, this week Chrome is rushing out a patch <https://issues.chromium.org/issues/381620359> that reverted a recent change that added support for the "Factory" zone by making it an alias for "Etc/Unknown". GIven that ICU previously didn't recognize Factory and so returned Etc/Unknown for computers in the Factory zone, this was assumed by everyone to be a safe change. But this change turned out to break some 3rd-party libraries and had to be reverted. After discussing this recent bug with engineers at Google, our consensus was that it'd be helpful for the time zone ecosystem if Etc/Unknown stopped being a special case and started being a regular Zone in the IANA Time Zone database. Especially if we could Link-ify Factory at the same time so that Zone picker UIs won't have two distinct "I don't know what time zone this is" choices. Thanks for considering this proposal. Best, Justin Grant

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[PROPOSED] Fix unlikely multithreaded file descriptor leak
by Paul Eggert Dec. 9, 2024

Dec. 9, 2024

On multithreaded platforms, tzset could leak a file descriptor into a forked or execed process. Fix the leak. While we’re at it, don’t let the TZif file become the controlling tty. * NEWS: Mention this. * localtime.c (O_CLOEXEC, O_CLOFORK, O_IGNORE_CTTY, O_NOCTTY): Default to 0. (tzloadbody): Use these flags when opening the TZif file. --- NEWS | 5 +++++ localtime.c | 22 +++++++++++++++++----- 2 files changed, 22 insertions(+), 5 deletions(-) diff --git a/NEWS b/NEWS index 79686147..2fc7bb19 100644 --- a/NEWS +++ b/NEWS @@ -56,6 +56,11 @@ Unreleased, experimental changes PTRDIFF_MAX, a limit forced by C anyway; formerly tzcode silently misbehaved unless TZNAME_MAXIMUM was less than INT_MAX. + tzset and related functions no longer leak a file descriptor if + another thread forks or execs at about the same time and if the + platform has O_CLOFORK and O_CLOEXEC respectively. Also, the + functions no longer let a TZif file become a controlling terminal. + Changes to documentation The name Etc/Unknown is now reserved: it will not be used by TZDB. diff --git a/localtime.c b/localtime.c index 492965d9..f92676c6 100644 --- a/localtime.c +++ b/localtime.c @@ -96,12 +96,23 @@ typedef intmax_t timex_t; # define TZ_ABBR_ERR_CHAR '_' #endif /* !defined TZ_ABBR_ERR_CHAR */ -/* -** Support non-POSIX platforms that distinguish between text and binary files. -*/ +/* Port to platforms that lack some O_* flags. Unless otherwise + specified, the flags are standardized by POSIX. */ #ifndef O_BINARY -# define O_BINARY 0 +# define O_BINARY 0 /* MS-Windows */ +#endif +#ifndef O_CLOEXEC +# define O_CLOEXEC 0 +#endif +#ifndef O_CLOFORK +# define O_CLOFORK 0 +#endif +#ifndef O_IGNORE_CTTY +# define O_IGNORE_CTTY 0 /* GNU/Hurd */ +#endif +#ifndef O_NOCTTY +# define O_NOCTTY 0 #endif #ifndef WILDABBR @@ -542,7 +553,8 @@ tzloadbody(char const *name, struct state *sp, bool doextend, } if (doaccess && access(name, R_OK) != 0) return errno; - fid = open(name, O_RDONLY | O_BINARY); + fid = open(name, (O_RDONLY | O_BINARY | O_CLOEXEC | O_CLOFORK + | O_IGNORE_CTTY | O_NOCTTY)); if (fid < 0) return errno; -- 2.47.0

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US Department of Transportation map of US timezones
by Roozbeh Pournader Dec. 7, 2024

Dec. 7, 2024

I just found out through https://x.com/RedistrictNet/status/1863742503242875046 That the US Department of Transportation has just rolled out an official map of US timezones. It's supposed to be at: https://geodata.bts.gov/datasets/usdot::time-zones/about (It doesn't load for me at the moment, possibly due to high demand.) Roozbeh

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[PROPOSED] Fix checknow confusing diagnostics
by Paul Eggert Dec. 7, 2024

Dec. 7, 2024

* checknow.awk: Do not report a duplicate (and confusing) diagnostic when a zone has no data. --- checknow.awk | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/checknow.awk b/checknow.awk index 8b7881d2..450490ee 100644 --- a/checknow.awk +++ b/checknow.awk @@ -44,7 +44,7 @@ BEGIN { END { for (zone in zone_data) { data = zone_data[zone] - if (!zonenow[data]) { + if (data && !zonenow[data]) { printf "Zone table should have one of:%s\n", zones[data] zonenow[data] = zone # This suppresses duplicate diagnostics. status = 1 -- 2.47.0

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[PROPOSED 1/3] Pacify gcc -Wsuggest-attribute=format sans snprintf in zdump
by Paul Eggert Dec. 1, 2024

Dec. 1, 2024

* zdump.c (my_snprintf): Now a static function defined only if !HAVE_SNPRINTF, with "#define snprintf my_sprintf" at the end. This lessens disruption to mainline code. All uses changed. Add ATTRIBUTE_FORMAT((printf, 3, 4)) to pacify gcc -Wsuggest-attribute=format. --- zdump.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) diff --git a/zdump.c b/zdump.c index c988f6b3..ea051adf 100644 --- a/zdump.c +++ b/zdump.c @@ -914,13 +914,10 @@ showextrema(timezone_t tz, char *zone, time_t lo, struct tm *lotmp, time_t hi) } } -#if HAVE_SNPRINTF -# define my_snprintf snprintf -#else +/* On pre-C99 platforms, a snprintf substitute good enough for us. */ +#if !HAVE_SNPRINTF # include <stdarg.h> - -/* A substitute for snprintf that is good enough for zdump. */ -static int +ATTRIBUTE_FORMAT((printf, 3, 4)) static int my_snprintf(char *s, size_t size, char const *format, ...) { int n; @@ -948,6 +945,7 @@ my_snprintf(char *s, size_t size, char const *format, ...) va_end(args); return n; } +# define snprintf my_snprintf #endif /* Store into BUF, of size SIZE, a formatted local time taken from *TM. @@ -962,10 +960,10 @@ format_local_time(char *buf, ptrdiff_t size, struct tm const *tm) { int ss = tm->tm_sec, mm = tm->tm_min, hh = tm->tm_hour; return (ss - ? my_snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss) + ? snprintf(buf, size, "%02d:%02d:%02d", hh, mm, ss) : mm - ? my_snprintf(buf, size, "%02d:%02d", hh, mm) - : my_snprintf(buf, size, "%02d", hh)); + ? snprintf(buf, size, "%02d:%02d", hh, mm) + : snprintf(buf, size, "%02d", hh)); } /* Store into BUF, of size SIZE, a formatted UT offset for the @@ -1000,10 +998,10 @@ format_utc_offset(char *buf, ptrdiff_t size, struct tm const *tm, time_t t) mm = off / 60 % 60; hh = off / 60 / 60; return (ss || 100 <= hh - ? my_snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss) + ? snprintf(buf, size, "%c%02ld%02d%02d", sign, hh, mm, ss) : mm - ? my_snprintf(buf, size, "%c%02ld%02d", sign, hh, mm) - : my_snprintf(buf, size, "%c%02ld", sign, hh)); + ? snprintf(buf, size, "%c%02ld%02d", sign, hh, mm) + : snprintf(buf, size, "%c%02ld", sign, hh)); } /* Store into BUF (of size SIZE) a quoted string representation of P. @@ -1106,7 +1104,7 @@ istrftime(char *buf, ptrdiff_t size, char const *time_fmt, for (abp = ab; is_alpha(*abp); abp++) continue; len = (!*abp && *ab - ? my_snprintf(b, s, "%s", ab) + ? snprintf(b, s, "%s", ab) : format_quoted_string(b, s, ab)); if (s <= len) return false; @@ -1114,7 +1112,7 @@ istrftime(char *buf, ptrdiff_t size, char const *time_fmt, } formatted_len = (tm->tm_isdst - ? my_snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst) + ? snprintf(b, s, &"\t\t%d"[show_abbr], tm->tm_isdst) : 0); } break; -- 2.43.0

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[PATCH 1/2] Be more consistent about macro true/false vs 1/0
by Paul Eggert Nov. 29, 2024

Nov. 29, 2024

* private.h (HAVE_GETTEXT, HAVE_SYS_STAT_H, HAVE_UNISTD_H) (HAVE_STDINT_H, HAVE_STRTOLL, HAVE_STDCKDINT_H) (HAVE_DECL_TIMEGM): * strftime.c (MKTIME_MIGHT_OVERFLOW, DEPRECATE_TWO_DIGIT_YEARS): Default to 1 or 0, not to true or false, since these can be set via the command line as per the Makefile. * private.h (TZ_TIME_T): Set to true or false, not to 1 or 0, since this is boolean and is not set via the command line. --- private.h | 26 +++++++++++++------------- strftime.c | 6 +++--- 2 files changed, 16 insertions(+), 16 deletions(-) diff --git a/private.h b/private.h index 6088d885..1e4e69a4 100644 --- a/private.h +++ b/private.h @@ -88,11 +88,11 @@ #if !defined HAVE_GETTEXT && defined __has_include # if __has_include(<libintl.h>) -# define HAVE_GETTEXT true +# define HAVE_GETTEXT 1 # endif #endif #ifndef HAVE_GETTEXT -# define HAVE_GETTEXT false +# define HAVE_GETTEXT 0 #endif #ifndef HAVE_INCOMPATIBLE_CTIME_R @@ -125,20 +125,20 @@ #if !defined HAVE_SYS_STAT_H && defined __has_include # if !__has_include(<sys/stat.h>) -# define HAVE_SYS_STAT_H false +# define HAVE_SYS_STAT_H 0 # endif #endif #ifndef HAVE_SYS_STAT_H -# define HAVE_SYS_STAT_H true +# define HAVE_SYS_STAT_H 1 #endif #if !defined HAVE_UNISTD_H && defined __has_include # if !__has_include(<unistd.h>) -# define HAVE_UNISTD_H false +# define HAVE_UNISTD_H 0 # endif #endif #ifndef HAVE_UNISTD_H -# define HAVE_UNISTD_H true +# define HAVE_UNISTD_H 1 #endif #ifndef NETBSD_INSPIRED @@ -312,7 +312,7 @@ ** stdint.h, even with pre-C99 compilers. */ #if !defined HAVE_STDINT_H && defined __has_include -# define HAVE_STDINT_H true /* C23 __has_include implies C99 stdint.h. */ +# define HAVE_STDINT_H 1 /* C23 __has_include implies C99 stdint.h. */ #endif #ifndef HAVE_STDINT_H # define HAVE_STDINT_H \ @@ -386,7 +386,7 @@ typedef int int_fast32_t; # ifdef LLONG_MAX typedef long long intmax_t; # ifndef HAVE_STRTOLL -# define HAVE_STRTOLL true +# define HAVE_STRTOLL 1 # endif # if HAVE_STRTOLL # define strtoimax strtoll @@ -466,7 +466,7 @@ typedef unsigned long uintmax_t; hosts, unless compiled with -DHAVE_STDCKDINT_H=0 or with pre-C23 EDG. */ #if !defined HAVE_STDCKDINT_H && defined __has_include # if __has_include(<stdckdint.h>) -# define HAVE_STDCKDINT_H true +# define HAVE_STDCKDINT_H 1 # endif #endif #ifdef HAVE_STDCKDINT_H @@ -634,9 +634,9 @@ typedef unsigned long uintmax_t; ** typical platforms. */ #if defined time_tz || EPOCH_LOCAL || EPOCH_OFFSET != 0 -# define TZ_TIME_T 1 +# define TZ_TIME_T true #else -# define TZ_TIME_T 0 +# define TZ_TIME_T false #endif #if defined LOCALTIME_IMPLEMENTATION && TZ_TIME_T @@ -753,9 +753,9 @@ void tzset(void); || defined __GLIBC__ || defined __tm_zone /* musl */ \ || defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ \ || (defined __APPLE__ && defined __MACH__)) -# define HAVE_DECL_TIMEGM true +# define HAVE_DECL_TIMEGM 1 # else -# define HAVE_DECL_TIMEGM false +# define HAVE_DECL_TIMEGM 0 # endif #endif #if !HAVE_DECL_TIMEGM && !defined timegm diff --git a/strftime.c b/strftime.c index fc0c87d2..487a5234 100644 --- a/strftime.c +++ b/strftime.c @@ -79,9 +79,9 @@ !defined __NetBSD_Version__ || __NetBSD_Version__ < 600000000) \ && (/* OpenBSD 5.5 (2014-05-01) and later has 64-bit time_t. */ \ !defined OpenBSD || OpenBSD < 201405))) -# define MKTIME_MIGHT_OVERFLOW true +# define MKTIME_MIGHT_OVERFLOW 1 # else -# define MKTIME_MIGHT_OVERFLOW false +# define MKTIME_MIGHT_OVERFLOW 0 # endif #endif /* Check that MKTIME_MIGHT_OVERFLOW is consistent with time_t's range. */ @@ -95,7 +95,7 @@ static_assert(MKTIME_MIGHT_OVERFLOW #endif #ifndef DEPRECATE_TWO_DIGIT_YEARS -# define DEPRECATE_TWO_DIGIT_YEARS false +# define DEPRECATE_TWO_DIGIT_YEARS 0 #endif struct lc_time_T { -- 2.43.0

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[PROPOSED 1/2] Remove dependency of asctime on strftime
by Paul Eggert Nov. 28, 2024

Nov. 28, 2024

Also, remove calls to strlen and strcpy. * asctime.c (ASCTIME_FMT, ASCTIME_FMT_B): Remove; the strings are now merely literals in asctime_r. (SNPRINTF, SNPRINTFBUF): New macros. (asctime_r): Do not call strftime %Y, as this is dicey when tm_year is not a value that could be yielded by localtime. Instead, use snprintf, or sprintf on ancient hosts lacking snprintf. Also, rely on snprintf/sprintf's return value instead of calling strlen, as it's safe to assume C89 b6 now. If snprintf is available, output to the result buffer directly instead of to the stack and then copying. This saves one call to strftime, two calls to strlen, and one call to strcpy. * private.h (HAVE_SNPRINTF): Move here ... * zdump.c: ... from here. --- asctime.c | 96 +++++++++++++++++++++++++++++++------------------------ private.h | 4 +++ zdump.c | 4 --- 3 files changed, 58 insertions(+), 46 deletions(-) diff --git a/asctime.c b/asctime.c index f75ec868..7bc19fd1 100644 --- a/asctime.c +++ b/asctime.c @@ -7,6 +7,7 @@ /* ** Avoid the temptation to punt entirely to strftime; +** strftime can behave badly when tm components are out of range, and ** the output of strftime is supposed to be locale specific ** whereas the output of asctime is supposed to be constant. */ @@ -16,27 +17,6 @@ #include "private.h" #include <stdio.h> -/* -** All years associated with 32-bit time_t values are exactly four digits long; -** some years associated with 64-bit time_t values are not. -** Vintage programs are coded for years that are always four digits long -** and may assume that the newline always lands in the same place. -** For years that are less than four digits, we pad the output with -** leading zeroes to get the newline in the traditional place. -** The -4 ensures that we get four characters of output even if -** we call a strftime variant that produces fewer characters for some years. -** This conforms to recent ISO C and POSIX standards, which say behavior -** is undefined when the year is less than 1000 or greater than 9999. -*/ -static char const ASCTIME_FMT[] = "%s %s%3d %.2d:%.2d:%.2d %-4s\n"; -/* -** For years that are more than four digits we put extra spaces before the year -** so that code trying to overwrite the newline won't end up overwriting -** a digit within a year and truncating the year (operating on the assumption -** that no output is better than wrong output). -*/ -static char const ASCTIME_FMT_B[] = "%s %s%3d %.2d:%.2d:%.2d %s\n"; - enum { STD_ASCTIME_BUF_SIZE = 26 }; /* ** Big enough for something such as @@ -84,8 +64,20 @@ asctime_r(struct tm const *restrict timeptr, char *restrict buf) }; register const char * wn; register const char * mn; - char year[INT_STRLEN_MAXIMUM(int) + 2]; - char result[sizeof buf_asctime]; + int year, mday, hour, min, sec; + size_t bufsize = ((buf == buf_ctime + || (!SUPPORT_C89 && buf == buf_asctime)) + ? sizeof buf_asctime : STD_ASCTIME_BUF_SIZE); +#if HAVE_SNPRINTF + char *result = buf; +# define SNPRINTF snprintf +# define SNPRINTFBUF(buf, bufsize) buf, bufsize +#else + char stackbuf[sizeof buf_asctime]; + char *result = stackbuf; +# define SNPRINTF sprintf +# define SNPRINTFBUF(buf, bufsize) buf +#endif if (timeptr == NULL) { errno = EINVAL; @@ -97,26 +89,46 @@ asctime_r(struct tm const *restrict timeptr, char *restrict buf) if (timeptr->tm_mon < 0 || timeptr->tm_mon >= MONSPERYEAR) mn = "???"; else mn = mon_name[timeptr->tm_mon]; - /* - ** Use strftime's %Y to generate the year, to avoid overflow problems - ** when computing timeptr->tm_year + TM_YEAR_BASE. - ** Assume that strftime is unaffected by other out-of-range members - ** (e.g., timeptr->tm_mday) when processing "%Y". - */ - strftime(year, sizeof year, "%Y", timeptr); - /* - ** We avoid using snprintf since it's not available on all systems. - */ - sprintf(result, - ((strlen(year) <= 4) ? ASCTIME_FMT : ASCTIME_FMT_B), - wn, mn, - timeptr->tm_mday, timeptr->tm_hour, - timeptr->tm_min, timeptr->tm_sec, - year); - if (strlen(result) < STD_ASCTIME_BUF_SIZE - || buf == buf_ctime || buf == buf_asctime) + + year = timeptr->tm_year; + mday = timeptr->tm_mday; + hour = timeptr->tm_hour; + min = timeptr->tm_min; + sec = timeptr->tm_sec; + + /* Vintage programs are coded for years that are always four bytes long + and may assume that the newline always lands in the same place. + For years that are less than four bytes, pad the output with + leading zeroes to get the newline in the traditional place. + For years longer than four bytes, put extra spaces before the year + so that vintage code trying to overwrite the newline + won't overwrite a digit within a year and truncate the year, + using the principle that no output is better than wrong output. + This conforms to ISO C and POSIX standards, which say behavior + is undefined when the year is less than 1000 or greater than 9999. + + Also, avoid overflow when formatting tm_year + TM_YEAR_BASE. */ + + if ((year <= INT_MAX - TM_YEAR_BASE + ? SNPRINTF (SNPRINTFBUF(result, bufsize), + ((-999 - TM_YEAR_BASE <= year + && year <= 9999 - TM_YEAR_BASE) + ? "%s %s%3d %.2d:%.2d:%.2d %04d\n" + : "%s %s%3d %.2d:%.2d:%.2d %d\n"), + wn, mn, mday, hour, min, sec, + year + TM_YEAR_BASE) + : SNPRINTF (SNPRINTFBUF(result, bufsize), + "%s %s%3d %.2d:%.2d:%.2d %d%d\n", + wn, mn, mday, hour, min, sec, + year / 10 + TM_YEAR_BASE / 10, + year % 10)) + < bufsize) { +#if HAVE_SNPRINTF + return buf; +#else return strcpy(buf, result); - else { +#endif + } else { errno = EOVERFLOW; return NULL; } diff --git a/private.h b/private.h index da6dc790..6088d885 100644 --- a/private.h +++ b/private.h @@ -263,6 +263,10 @@ # endif #endif +#ifndef HAVE_SNPRINTF +# define HAVE_SNPRINTF (!PORT_TO_C89 || 199901 <= __STDC_VERSION__) +#endif + #ifndef HAVE_STRFTIME_L # if _POSIX_VERSION < 200809 # define HAVE_STRFTIME_L 0 diff --git a/zdump.c b/zdump.c index 2c6725e5..c988f6b3 100644 --- a/zdump.c +++ b/zdump.c @@ -14,10 +14,6 @@ #include "private.h" #include <stdio.h> -#ifndef HAVE_SNPRINTF -# define HAVE_SNPRINTF (!PORT_TO_C89 || 199901 <= __STDC_VERSION__) -#endif - #ifndef HAVE_LOCALTIME_R # define HAVE_LOCALTIME_R 1 #endif -- 2.43.0

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[PROPOSED 1/2] Move MKTIME_MIGHT_OVERFLOW definition
by Paul Eggert Nov. 27, 2024

Nov. 27, 2024

* private.h (MKTIME_FITS_IN, MKTIME_MIGHT_OVERFLOW): Move definitions from here ... * strftime.c: ... to here, as it’s the only file needing them. --- private.h | 49 ------------------------------------------------- strftime.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+), 49 deletions(-) diff --git a/private.h b/private.h index fc0b8755..95ab2e1d 100644 --- a/private.h +++ b/private.h @@ -914,55 +914,6 @@ enum { SIGNED_PADDING_CHECK_NEEDED = true }; static_assert(! TYPE_SIGNED(time_t) || ! SIGNED_PADDING_CHECK_NEEDED || TIME_T_MAX >> (TYPE_BIT(time_t) - 2) == 1); -/* If true, the value returned by an idealized unlimited-range mktime - always fits into an integer type with bounds MIN and MAX. - If false, the value might not fit. - This macro is usable in #if if its arguments are. - Add or subtract 2**31 - 1 for the maximum UT offset allowed in a TZif file, - divide by the maximum number of non-leap seconds in a year, - divide again by two just to be safe, - and account for the tm_year origin (1900) and time_t origin (1970). */ -#define MKTIME_FITS_IN(min, max) \ - ((min) < 0 \ - && ((min) + 0x7fffffff) / 366 / 24 / 60 / 60 / 2 + 1970 - 1900 < INT_MIN \ - && INT_MAX < ((max) - 0x7fffffff) / 366 / 24 / 60 / 60 / 2 + 1970 - 1900) - -/* MKTIME_MIGHT_OVERFLOW is true if mktime can fail due to time_t overflow - or if it is not known whether mktime can fail, - and is false if mktime definitely cannot fail. - This macro is usable in #if, and so does not use TIME_T_MAX or sizeof. - If the builder has not configured this macro, guess based on what - known platforms do. When in doubt, guess true. */ -#ifndef MKTIME_MIGHT_OVERFLOW -# if defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ -# include <sys/param.h> -# endif -# if ((/* The following heuristics assume native time_t. */ \ - defined_time_tz) \ - || ((/* Traditional time_t is 'long', so if 'long' is not wide enough \ - assume overflow unless we're on a known-safe host. */ \ - !MKTIME_FITS_IN(LONG_MIN, LONG_MAX)) \ - && (/* GNU C Library 2.29 (2019-02-01) and later has 64-bit time_t \ - if __TIMESIZE is 64. */ \ - !defined __TIMESIZE || __TIMESIZE < 64) \ - && (/* FreeBSD 12 r320347 (__FreeBSD_version 1200036; 2017-06-26), \ - and later has 64-bit time_t on all platforms but i386 which \ - is currently scheduled for end-of-life on 2028-11-30. */ \ - !defined __FreeBSD_version || __FreeBSD_version < 1200036 \ - || defined __i386) \ - && (/* NetBSD 6.0 (2012-10-17) and later has 64-bit time_t. */ \ - !defined __NetBSD_Version__ || __NetBSD_Version__ < 600000000) \ - && (/* OpenBSD 5.5 (2014-05-01) and later has 64-bit time_t. */ \ - !defined OpenBSD || OpenBSD < 201405))) -# define MKTIME_MIGHT_OVERFLOW true -# else -# define MKTIME_MIGHT_OVERFLOW false -# endif -#endif -/* Check that MKTIME_MIGHT_OVERFLOW is consistent with time_t's range. */ -static_assert(MKTIME_MIGHT_OVERFLOW - || MKTIME_FITS_IN(TIME_T_MIN, TIME_T_MAX)); - /* ** 302 / 1000 is log10(2.0) rounded up. ** Subtract one for the sign bit if the type is signed; diff --git a/strftime.c b/strftime.c index 7be94de3..fc0c87d2 100644 --- a/strftime.c +++ b/strftime.c @@ -39,6 +39,55 @@ #include <locale.h> #include <stdio.h> +/* If true, the value returned by an idealized unlimited-range mktime + always fits into an integer type with bounds MIN and MAX. + If false, the value might not fit. + This macro is usable in #if if its arguments are. + Add or subtract 2**31 - 1 for the maximum UT offset allowed in a TZif file, + divide by the maximum number of non-leap seconds in a year, + divide again by two just to be safe, + and account for the tm_year origin (1900) and time_t origin (1970). */ +#define MKTIME_FITS_IN(min, max) \ + ((min) < 0 \ + && ((min) + 0x7fffffff) / 366 / 24 / 60 / 60 / 2 + 1970 - 1900 < INT_MIN \ + && INT_MAX < ((max) - 0x7fffffff) / 366 / 24 / 60 / 60 / 2 + 1970 - 1900) + +/* MKTIME_MIGHT_OVERFLOW is true if mktime can fail due to time_t overflow + or if it is not known whether mktime can fail, + and is false if mktime definitely cannot fail. + This macro is usable in #if, and so does not use TIME_T_MAX or sizeof. + If the builder has not configured this macro, guess based on what + known platforms do. When in doubt, guess true. */ +#ifndef MKTIME_MIGHT_OVERFLOW +# if defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ +# include <sys/param.h> +# endif +# if ((/* The following heuristics assume native time_t. */ \ + defined_time_tz) \ + || ((/* Traditional time_t is 'long', so if 'long' is not wide enough \ + assume overflow unless we're on a known-safe host. */ \ + !MKTIME_FITS_IN(LONG_MIN, LONG_MAX)) \ + && (/* GNU C Library 2.29 (2019-02-01) and later has 64-bit time_t \ + if __TIMESIZE is 64. */ \ + !defined __TIMESIZE || __TIMESIZE < 64) \ + && (/* FreeBSD 12 r320347 (__FreeBSD_version 1200036; 2017-06-26), \ + and later has 64-bit time_t on all platforms but i386 which \ + is currently scheduled for end-of-life on 2028-11-30. */ \ + !defined __FreeBSD_version || __FreeBSD_version < 1200036 \ + || defined __i386) \ + && (/* NetBSD 6.0 (2012-10-17) and later has 64-bit time_t. */ \ + !defined __NetBSD_Version__ || __NetBSD_Version__ < 600000000) \ + && (/* OpenBSD 5.5 (2014-05-01) and later has 64-bit time_t. */ \ + !defined OpenBSD || OpenBSD < 201405))) +# define MKTIME_MIGHT_OVERFLOW true +# else +# define MKTIME_MIGHT_OVERFLOW false +# endif +#endif +/* Check that MKTIME_MIGHT_OVERFLOW is consistent with time_t's range. */ +static_assert(MKTIME_MIGHT_OVERFLOW + || MKTIME_FITS_IN(TIME_T_MIN, TIME_T_MAX)); + #if MKTIME_MIGHT_OVERFLOW /* Do this after system includes as it redefines time_t, mktime, timeoff. */ # define USE_TIMEX_T true -- 2.47.0

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[PROPOSED 1/2] Pacify GCC 15ish -Wleading-whitespace=blanks
by Paul Eggert Nov. 27, 2024

Nov. 27, 2024

Normalize indentation in a few source files to pacify gcc -Wleading-whitespace=blanks (in the forthcoming GCC 15). --- localtime.c | 2 +- private.h | 2 +- zdump.c | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) diff --git a/localtime.c b/localtime.c index ea2a6fb8..e6d79d05 100644 --- a/localtime.c +++ b/localtime.c @@ -1770,7 +1770,7 @@ timesub(const time_t *timep, int_fast32_t offset, dayoff = offset / SECSPERDAY - corr / SECSPERDAY + rem / SECSPERDAY - 3; rem %= SECSPERDAY; /* y = (EPOCH_YEAR - + floor((tdays + dayoff) / DAYSPERREPEAT) * YEARSPERREPEAT), + + floor((tdays + dayoff) / DAYSPERREPEAT) * YEARSPERREPEAT), sans overflow. But calculate against 1570 (EPOCH_YEAR - YEARSPERREPEAT) instead of against 1970 so that things work for localtime values before 1970 when time_t is unsigned. */ diff --git a/private.h b/private.h index bdd00013..fc0b8755 100644 --- a/private.h +++ b/private.h @@ -897,7 +897,7 @@ ATTRIBUTE_PURE time_t time2posix_z(timezone_t, time_t); default: TIME_T_MAX_NO_PADDING) \ : (time_t) -1) enum { SIGNED_PADDING_CHECK_NEEDED - = _Generic((time_t) 0, + = _Generic((time_t) 0, signed char: false, short: false, int: false, long: false, long long: false, default: true) }; diff --git a/zdump.c b/zdump.c index b668022d..2c6725e5 100644 --- a/zdump.c +++ b/zdump.c @@ -687,7 +687,7 @@ yeartot(intmax_t y) return absolute_max_time; seconds = diff400 * SECSPER400YEARS; years = diff400 * 400; - } else { + } else { seconds = isleap(myy) ? SECSPERLYEAR : SECSPERNYEAR; years = 1; } -- 2.43.0

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New timezone Antarctica/Concordia (UTC+8)
by Erik Geletti Nov. 26, 2024

Nov. 26, 2024

Goodmorning. I'm writing here to propose a new time zone for an all-year open Antarctic base. The base is a French–Italian research facility that was built 3,233 m (10,607 ft) above sea level at a location called Dome C on the Antarctic Plateau, Antarctica. https://en.wikipedia.org/wiki/Concordia_Station The timezone is UTC+8 without DST. Best regards, Erik Geletti -- Erik Geletti Servizi Tecnici ed Informatici Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS Borgo Grotta Gigante n. 42/c 34010 Sgonico (Trieste) - Italia Tel. 0402140286 www.ogs.it

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[PROPOSED 1/2] Move iinntt definition
by Paul Eggert Nov. 24, 2024

Nov. 24, 2024

It’s used only in localtime.c, so move its definition there. * localtime.c (IINNTT_MIN, IINNTT_MAX, iinntt): Move to here ... * private.h: ... from here. --- localtime.c | 18 ++++++++++++++++++ private.h | 17 ----------------- 2 files changed, 18 insertions(+), 17 deletions(-) diff --git a/localtime.c b/localtime.c index 14c356e1..1d42fc36 100644 --- a/localtime.c +++ b/localtime.c @@ -29,6 +29,24 @@ static int lock(void) { return 0; } static void unlock(void) { } #endif +/* A signed type wider than int, so that we can add 1900 + tm_mon/12 to tm_year + without overflow. The static_assert checks that it is indeed wider + than int; if this fails on your platform please let us know. */ +#if INT_MAX < LONG_MAX +typedef long iinntt; +# define IINNTT_MIN LONG_MIN +# define IINNTT_MAX LONG_MAX +#elif INT_MAX < LLONG_MAX +typedef long long iinntt; +# define IINNTT_MIN LLONG_MIN +# define IINNTT_MAX LLONG_MAX +#else +typedef intmax_t iinntt; +# define IINNTT_MIN INTMAX_MIN +# define IINNTT_MAX INTMAX_MAX +#endif +static_assert(IINNTT_MIN < INT_MIN && INT_MAX < IINNTT_MAX); + /* On platforms where offtime or mktime might overflow, strftime.c defines USE_TIMEX_T to be true and includes us. This tells us to #define time_t to an internal type timex_t that is diff --git a/private.h b/private.h index 3a699f0f..bdd00013 100644 --- a/private.h +++ b/private.h @@ -450,23 +450,6 @@ typedef unsigned long uintmax_t; #endif /* PORT_TO_C89 */ -/* A signed type wider than int, so that we can add 1900 to tm_year - without overflow. */ -#if INT_MAX < LONG_MAX -typedef long iinntt; -# define IINNTT_MIN LONG_MIN -# define IINNTT_MAX LONG_MAX -#elif INT_MAX < LLONG_MAX -typedef long long iinntt; -# define IINNTT_MIN LLONG_MIN -# define IINNTT_MAX LLONG_MAX -#else -typedef intmax_t iinntt; -# define IINNTT_MIN INTMAX_MIN -# define IINNTT_MAX INTMAX_MAX -#endif -static_assert(IINNTT_MIN < INT_MIN && INT_MAX < IINNTT_MAX); - /* The maximum size of any created object, as a signed integer. Although the C standard does not outright prohibit larger objects, behavior is undefined if the result of pointer subtraction does not -- 2.43.0

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Re: [PROPOSED 4/6] Fix bug near the year 2**31 - 1 - 1900
by Paul Eggert Nov. 23, 2024

Nov. 23, 2024

On 2024-11-22 22:08, Magnus Fromreide wrote: > The definition of iinntt does not guarantee that it is wider than an int, > does something break if INT_MAX == INTMAX_MAX and INT_MIN == INTMAX_MIN? That's checked statically by "static_assert(IINNTT_MIN < INT_MIN && INT_MAX < IINNTT_MAX);". I don't know of any tzcode platform where that static assertion would fail (and thus break the build) because no signed type is wider than 'int'. If you know of one, please let us know.

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(unofficial) Australian Central Western Time
by Stuart Bishop Nov. 22, 2024

Nov. 22, 2024

An article discussing the in-use but technically unofficial timezones in the Western Australian portion of the Nullarbor Plain. https://www.abc.net.au/news/2024-11-22/outback-wa-properties-strange-time-z… -- Stuart Bishop <stuart(a)stuartbishop.net> http://www.stuartbishop.net/

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[PROPOSED] Avoid time_t + int overflow
by Paul Eggert Nov. 22, 2024

Nov. 22, 2024

* localtime.c (increment_overflow_time_int): New function. (time2sub): Use it (instead of relying on possibly-undefined behavior) to check for time_t + int overflow. --- localtime.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/localtime.c b/localtime.c index 07ce41b8..14c356e1 100644 --- a/localtime.c +++ b/localtime.c @@ -1882,6 +1882,21 @@ increment_overflow_iinntt(iinntt *lp, int m) #endif } +static bool +increment_overflow_time_int(time_t *tp, int j) +{ +#ifdef ckd_add + return ckd_add(tp, *tp, j); +#else + if (j < 0 + ? (TYPE_SIGNED(time_t) ? *tp < TIME_T_MIN - j : *tp <= -1 - j) + : TIME_T_MAX - j < *tp) + return true; + *tp += j; + return false; +#endif +} + static bool increment_overflow_time(time_t *tp, int_fast32_t j) { @@ -2155,10 +2170,8 @@ time2sub(struct tm *const tmp, return WRONG; } label: - newt = t + saved_seconds; - if ((newt < t) != (saved_seconds < 0)) + if (increment_overflow_time_int(&t, saved_seconds)) return WRONG; - t = newt; if (funcp(sp, &t, offset, tmp)) *okayp = true; return t; -- 2.47.0

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