update to 2025a

Changes to code

strftime %s now generates the correct numeric string even when the
represented number does not fit into time_t. This is better than
generating the num

update to 2025a

Changes to code

strftime %s now generates the correct numeric string even when the
represented number does not fit into time_t. This is better than
generating the numeric equivalent of (time_t) -1, as strftime did
in TZDB releases 96a (when %s was introduced) through 2020a and in
releases 2022b through 2024b. It is also better than failing and
returning 0, as strftime did in releases 2020b through 2022a.

strftime now outputs an invalid conversion specifier as-is,
instead of eliding the leading '%', which confused debugging.

An invalid TZ now generates the time zone abbreviation "-00", not
"UTC", to help the user see that an error has occurred. (Thanks
to Arthur David Olson for suggesting a "wrong result".)

mktime and timeoff no longer incorrectly fail merely because a
struct tm component near INT_MIN or INT_MAX overflows when a
lower-order component carries into it.

TZNAME_MAXIMUM, the maximum number of bytes in a proleptic TZ
string's time zone abbreviation, now defaults to 254 not 255.
This helps reduce the size of internal state from 25480 to 21384
on common platforms. This change should not be a problem, as
nobody uses such long "abbreviations" and the longstanding tzcode
maximum was 16 until release 2023a. For those who prefer no
arbitrary limits, you can now specify TZNAME_MAXIMUM values up to
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.

'zdump -' now reads TZif data from /dev/stdin.
(From a question by Arthur David Olson.)

show more ...

Merge tzcode-2024b

Release 2024b - 2024-09-04 12:27:47 -0700

Changes to code

localtime.c now always uses a TZif file's time type 0 to handle
timestamps before the file's first transition

Merge tzcode-2024b

Release 2024b - 2024-09-04 12:27:47 -0700

Changes to code

localtime.c now always uses a TZif file's time type 0 to handle
timestamps before the file's first transition. Formerly,
localtime.c sometimes inferred a different time type, in order to
handle problematic data generated by zic 2018e or earlier. As it
is now safe to assume more recent versions of zic, there is no
longer a pressing need to fail to conform RFC 8536 section 3.2,
which requires using time type 0 in this situation. This change
does not affect behavior when reading TZif files generated by zic
2018f and later.

POSIX.1-2024 removes asctime_r and ctime_r and does not let
libraries define them, so remove them except when needed to
conform to earlier POSIX. These functions are dangerous as they
can overrun user buffers. If you still need them, add
-DSUPPORT_POSIX2008 to CFLAGS.

The SUPPORT_C89 option now defaults to 1 instead of 0, fixing a
POSIX-conformance bug introduced in 2023a.

tzselect now supports POSIX.1-2024 proleptic TZ strings. Also, it
assumes POSIX.2-1992 or later, as practical porting targets now
all support that, and it uses some features from POSIX.1-2024 if
available.

Changes to build procedure

'make check' no longer requires curl and Internet access.

The build procedure now assumes POSIX.2-1992 or later, to simplify
maintenance. To build on Solaris 10, the only extant system still
defaulting to pre-POSIX, prepend /usr/xpg4/bin to PATH.

Changes to documentation

The documentation now reflects POSIX.1-2024.

Changes to commentary

Commentary about historical transitions in Portugal and her former
colonies has been expanded with links to many relevant legislation.
(Thanks to Tim Parenti.)

show more ...

s/of of/of/ in comment.

Update tzcode from 2022g to 2023c:

Release 2023c - 2023-03-28 12:42:14 -0700

Release 2023b - 2023-03-23 19:50:38 -0700

Release 2023a - 2023-03-22 12:39:33 -0700

Changes to code

You can now

Update tzcode from 2022g to 2023c:

Release 2023c - 2023-03-28 12:42:14 -0700

Release 2023b - 2023-03-23 19:50:38 -0700

Release 2023a - 2023-03-22 12:39:33 -0700

Changes to code

You can now tell tzselect local time, to simplify later choices.
Select the 'time' option in its first prompt.

You can now compile with -DTZNAME_MAXIMUM=N to limit time zone
abbreviations to N bytes (default 255). The reference runtime
library now rejects POSIX-style TZ strings that contain longer
abbreviations, treating them as UTC. Previously the limit was
platform dependent and abbreviations were silently truncated to
16 bytes even when the limit was greater than 16.

The code by default is now designed for C99 or later. To build in
a C89 environment, compile with -DPORT_TO_C89. To support C89
callers of the tzcode library, compile with -DSUPPORT_C89. The
two new macros are transitional aids planned to be removed in a
future version, when C99 or later will be required.

The code now builds again on pre-C99 platforms, if you compile
with -DPORT_TO_C89. This fixes a bug introduced in 2022f.

On C23-compatible platforms tzcode no longer uses syntax like
'static [[noreturn]] void usage(void);'. Instead, it uses
'[[noreturn]] static void usage(void);' as strict C23 requires.
(Problem reported by Houge Langley.)

The code's functions now constrain their arguments with the C
'restrict' keyword consistently with their documentation.
This may allow future optimizations.

zdump again builds standalone with ckdadd and without setenv,
fixing a bug introduced in 2022g. (Problem reported by panic.)

leapseconds.awk can now process a leap seconds file that never
expires; this might be useful if leap seconds are discontinued.

Changes to commentary

tz-link.html has a new section "Coordinating with governments and
distributors". (Thanks to Neil Fuller for some of the text.)

To improve tzselect diagnostics, zone1970.tab's comments column is
now limited to countries that have multiple timezones.

Note that leap seconds are planned to be discontinued by 2035.

show more ...

Apply 9cfe9507fcc22cd4a0c4da486ea1c7f0de6b075f for C23 attribute compliance.
Requested by Jan-Benedict Glaw.

Handle the case the code originally intended to handle; systems where:
SIZE_MAX < PTRDIFF_MAX

Merge in 2022g:

Although tzcode still works with C89, bugs found in recent routine
maintenance indicate that bitrot has set in and that in practice
C89 is no longer used to build tzcode.

Merge in 2022g:

Although tzcode still works with C89, bugs found in recent routine
maintenance indicate that bitrot has set in and that in practice
C89 is no longer used to build tzcode. As it is a maintenance
burden, support for C89 is planned to be removed soon. Instead,
please use compilers compatible with C99, C11, C17, or C23.

timegm, which tzcode implemented in 1989, will finally be
standardized 34 years later as part of C23, so timegm is now
supported even if STD_INSPIRED is not defined.

Fix bug in zdump's tzalloc emulation on hosts that lack tm_zone.
(Problem reported by Đoàn Trần Công Danh.)

Fix bug in zic on hosts where malloc(0) yields NULL on success.
(Problem reported by Tim McBrayer for AIX 6.1.)

Fix zic configuration to avoid linkage failures on some platforms.
(Problems reported by Gilmore Davidson and Igor Ivanov.)

Work around MS-Windows nmake incompatibility with POSIX.
(Problem reported by Manuela Friedrich.)

Port mktime and strftime to debugging platforms where accessing
uninitialized data has undefined behavior (strftime problem
reported by Robert Elz).

Check more carefully for unlikely integer overflows, preferring
C23 <stdckdint.h> to overflow checking by hand, as the latter has
had obscure bugs.

show more ...

Update to tzcode2022f

Changes to code

zic now supports links to links regardless of input line order.
For example, if Australia/Sydney is a Zone, the lines
Link Australia/Canberra A

Update to tzcode2022f

Changes to code

zic now supports links to links regardless of input line order.
For example, if Australia/Sydney is a Zone, the lines
Link Australia/Canberra Australia/ACT
Link Australia/Sydney Australia/Canberra
now work correctly, even though the shell commands
ln Australia/Canberra Australia/ACT
ln Australia/Sydney Australia/Canberra
would fail because the first command attempts to use a link
Australia/Canberra that does not exist until after the second
command is executed. Previously, zic had unspecified behavior if
a Link line's target was another link, and zic often misbehaved if
a Link line's target was a later Link line.

Fix line number in zic's diagnostic for a link to a link.

Fix a bug that caused localtime to mishandle timestamps starting
in the year 2438 when reading data generated by 'zic -b fat' when
distant-future DST transitions occur at times given in standard
time or in UT, not the usual case of local time. This occurs when
the corresponding .zi Rule lines specify DST transitions with TO
columns of 'max' and AT columns that end in 's' or 'u'. The
number 2438 comes from the 32-bit limit in the year 2038, plus the
400-year Gregorian cycle. (Problem reported by Bradley White.)

On glibc 2.34 and later, which optionally supports 64-bit time_t
on platforms like x86 where time_t was traditionally 32 bits,
default time_t to 64 instead of 32 bits. This lets functions like
localtime support timestamps after the year 2038, and fixes
year-2038 problems in zic when accessing files dated after 2038.
To continue to limit time_t to 32 bits on these platforms, use
"make CFLAGS='-D_TIME_BITS=32'".

In C code, do not enable large-file support on platforms like AIX
and macOS that no longer need it now that tzcode does not use
off_t or related functions like 'stat'. Large-file support is
still enabled by default on GNU/Linux, as it is needed for 64-bit
time_t support.

In C code, prefer C23 keywords to pre-C23 macros for alignof,
bool, false, and true. Also, use the following C23 features if
available: __has_include, unreachable.

zic no longer works around Qt bug 53071, as the relevant Qt
releases have been out of support since 2019. This change affects
only fat TZif files, as thin files never had the workaround.

zdump no longer modifies the environ vector when compiled on
platforms lacking tm_zone or when compiled with -DUSE_LTZ=0.
This avoid undefined behavior on POSIX platforms.

show more ...

Welcome to 2022b:

zic has a new option '-R @N' to output explicit transitions < N.
(Need suggested by Almaz Mingaleev.)

'zic -r @N' no longer outputs bad data when N < first transition.
(Problem in

Welcome to 2022b:

zic has a new option '-R @N' to output explicit transitions < N.
(Need suggested by Almaz Mingaleev.)

'zic -r @N' no longer outputs bad data when N < first transition.
(Problem introduced in 2021d and reported by Peter Krefting.)

zic now checks its input for NUL bytes and unterminated lines, and
now supports input line lengths up to 2048 (not 512) bytes.

gmtime and related code now use the abbreviation "UTC" not "GMT".
POSIX is being revised to require this.

When tzset and related functions set vestigial static variables
like tzname, they now prefer specified timestamps to unspecified ones.
(Problem reported by Almaz Mingaleev.)

zic no longer complains "can't determine time zone abbreviation to
use just after until time" when a transition to a new standard
time occurs simultanously with the first DST fallback transition.

show more ...

welcome to tzcode-2022a

Changes to code

Fix bug when mktime gets confused by truncated TZif files with
unspecified local time. (Problem reported by Almaz Mingaleev.)

Fix bug when 32

welcome to tzcode-2022a

Changes to code

Fix bug when mktime gets confused by truncated TZif files with
unspecified local time. (Problem reported by Almaz Mingaleev.)

Fix bug when 32-bit time_t code reads malformed 64-bit TZif data.
(Problem reported by Christos Zoulas.)

When reading a version 2 or later TZif file, the TZif reader now
validates the version 1 header and data block only enough to skip
over them, as recommended by RFC 8536 section 4. Also, the TZif
reader no longer mistakenly attempts to parse a version 1 TZIf
file header as a TZ string.

zdump -v now outputs "(localtime failed)" and "(gmtime failed)"
when local time and UT cannot be determined for a timestamp.

show more ...

Fix build failure

* Fix merge mistake.
* Cast to int for strict comparison like before.

Change to code and documentation from 2021a -> 2021e

Release 2021e - 2021-10-21 18:41:00 -0700

Changes to code

none


Release 2021d - 2021-10-15 13:48:18 -0700

Changes to code

'zic -

Change to code and documentation from 2021a -> 2021e

Release 2021e - 2021-10-21 18:41:00 -0700

Changes to code

none


Release 2021d - 2021-10-15 13:48:18 -0700

Changes to code

'zic -r' now uses "-00" time zone abbreviations for intervals
with UT offsets that are unspecified due to -r truncation.
This implements a change in draft Internet RFC 8536bis.


Release 2021c - 2021-10-01 14:21:49 -0700

Changes to code

Fix a bug in 'zic -b fat' that caused old timestamps to be
mishandled in 32-bit-only readers (problem reported by Daniel
Fischer).

Changes to documentation

Distribute the SECURITY file (problem reported by Andreas Radke).


Release 2021b - 2021-09-24 16:23:00 -0700

Changes to maintenance procedure

The new file SECURITY covers how to report security-related bugs.

Several backward-compatibility links have been moved to the
'backward' file. These links, which range from Africa/Addis_Ababa
to Pacific/Saipan, are only for compatibility with now-obsolete
guidelines suggesting an entry for every ISO 3166 code.
The intercontinental convenience links Asia/Istanbul and
Europe/Nicosia have also been moved to 'backward'.

Changes to code

zic now creates each output file or link atomically,
possibly by creating a temporary file and then renaming it.
This avoids races where a TZ setting would temporarily stop
working while zic was installing a replacement file or link.

zic -L no longer omits the POSIX TZ string in its output.
Starting with 2020a, zic -L truncated its output according to the
"Expires" directive or "#expires" comment in the leapseconds file.
The resulting TZif files omitted daylight saving transitions after
the leap second table expired, which led to far less-accurate
predictions of times after the expiry. Although future timestamps
cannot be converted accurately in the presence of leap seconds, it
is more accurate to convert near-future timestamps with a few
seconds error than with an hour error, so zic -L no longer
truncates output in this way.

Instead, when zic -L is given the "Expires" directive, it now
outputs the expiration by appending a no-change entry to the leap
second table. Although this should work well with most TZif
readers, it does not conform to Internet RFC 8536 and some pickier
clients (including tzdb 2017c through 2021a) reject it, so
"Expires" directives are currently disabled by default. To enable
them, set the EXPIRES_LINE Makefile variable. If a TZif file uses
this new feature it is marked with a new TZif version number 4,
a format intended to be documented in a successor to RFC 8536.

zic -L LEAPFILE -r @LO no longer generates an invalid TZif file
that omits leap second information for the range LO..B when LO
falls between two leap seconds A and B. Instead, it generates a
TZif version 4 file that represents the previously-missing
information.

The TZif reader now allows the leap second table to begin with a
correction other than -1 or +1, and to contain adjacent
transitions with equal corrections. This supports TZif version 4.

The TZif reader now lets leap seconds occur less than 28 days
apart. This supports possible future TZif extensions.

Fix bug that caused 'localtime' etc. to crash when TZ was
set to a all-year DST string like "EST5EDT4,0/0,J365/25" that does
not conform to POSIX but does conform to Internet RFC 8536.

Fix another bug that caused 'localtime' etc. to crash when TZ was
set to a POSIX-conforming but unusual TZ string like
"EST5EDT4,0/0,J365/0", where almost all the year is DST.

Fix yet another bug that caused 'localtime' etc. to mishandle slim
TZif files containing leap seconds after the last explicit
transition in the table, or when handling far-future timestamps
in slim TZif files lacking leap seconds.

Fix localtime misbehavior involving positive leap seconds.
This change affects only behavior for "right" system time,
which contains leap seconds, and only if the UT offset is
not a multiple of 60 seconds when a positive leap second occurs.
(No such timezone exists in tzdb, luckily.) Without the fix,
the timestamp was ambiguous during a positive leap second.
With the fix, any seconds occurring after a positive leap second
and within the same localtime minute are counted through 60, not
through 59; their UT offset (tm_gmtoff) is the same as before.
Here is how the fix affects timestamps in a timezone with UT
offset +01:23:45 (5025 seconds) and with a positive leap second at
1972-06-30 23:59:60 UTC (78796800):

time_t without the fix with the fix
78796800 1972-07-01 01:23:45 1972-07-01 01:23:45 (leap second)
78796801 1972-07-01 01:23:45 1972-07-01 01:23:46
...
78796815 1972-07-01 01:23:59 1972-07-01 01:23:60
78796816 1972-07-01 01:24:00 1972-07-01 01:24:00

Fix an unlikely bug that caused 'localtime' etc. to misbehave if
civil time changes a few seconds before time_t wraps around, when
leap seconds are enabled.

Fix bug in zic -r; in some cases, the dummy time type after the
last time transition disagreed with the TZ string, contrary to
Internet RFC 8563 section 3.3.

Fix a bug with 'zic -r @X' when X is a negative leap second that
has a nonnegative correction. Without the fix, the output file
was truncated so that X appeared to be a positive leap second.
Fix a similar, even-less-likely bug when truncating at a positive
leap second that has a nonpositive correction.

zic -r now reports an error if given rolling leap seconds, as this
usage has never generally worked and is evidently unused.

zic now generates a POSIX-conforming TZ string for TZif files
where all-year DST is predicted for the indefinite future.
For example, for all-year Eastern Daylight Time, zic now generates
"XXX3EDT4,0/0,J365/23" where it previously generated
"EST5EDT,0/0,J365/25" or "". (Thanks to Michael Deckers for
noting the possibility of POSIX conformance.)

zic.c no longer requires sys/wait.h (thanks to spazmodius for
noting it wasn't needed).

When reading slim TZif files, zdump no longer mishandles leap
seconds on the rare platforms where time_t counts leap seconds,
fixing a bug introduced in 2014g.

zdump -v now outputs timestamps at boundaries of what localtime
and gmtime can represent, instead of the less-useful timestamps
one day after the minimum and one day before the maximum.
(Thanks to Arthur David Olson for prototype code, and to Manuela
Friedrich for debugging help.)

zdump's -c and -t options are now consistently inclusive for the
lower time bound and exclusive for the upper. Formerly they were
inconsistent. (Confusion noted by Martin Burnicki.)

Changes to build procedure

You can now compile with -DHAVE_MALLOC_ERRNO=0 to port to
non-POSIX hosts where malloc doesn't set errno.
(Problem reported by Jan Engelhardt.)

Changes to documentation

tzfile.5 better matches a draft successor to RFC 8536
<https://datatracker.ietf.org/doc/draft-murchison-rfc8536bis/01/>.

show more ...

Bring in 2020a

Merge the [pgoyette-compat] branch

Release 2018i - 2018-12-30 11:05:43 -0800

Briefly:
São Tomé and Príncipe switches from +01 to +00 on 2019-01-01.

Changes to future timestamps

Due to a change in government, São Tomé an

Release 2018i - 2018-12-30 11:05:43 -0800

Briefly:
São Tomé and Príncipe switches from +01 to +00 on 2019-01-01.

Changes to future timestamps

Due to a change in government, São Tomé and Príncipe switches back
from +01 to +00 on 2019-01-01 at 02:00. (Thanks to Vadim
Nasardinov and Michael Deckers.)


Release 2018h - 2018-12-23 17:59:32 -0800

Briefly:
Qyzylorda, Kazakhstan moved from +06 to +05 on 2018-12-21.
New zone Asia/Qostanay because Qostanay, Kazakhstan didn't move.
Metlakatla, Alaska observes PST this winter only.
Guess Morocco will continue to adjust clocks around Ramadan.
Add predictions for Iran from 2038 through 2090.

Changes to future timestamps

Guess that Morocco will continue to fall back just before and
spring forward just after Ramadan, the practice since 2012.
(Thanks to Maamar Abdelkader.) This means Morocco will observe
negative DST during Ramadan in main and vanguard formats, and in
rearguard format it stays in the +00 timezone and observes
ordinary DST in all months other than Ramadan. As before, extend
this guesswork to the year 2037. As a consequence, Morocco is
scheduled to observe three DST transitions in some Gregorian years
(e.g., 2033) due to the mismatch between the Gregorian and Islamic
calendars.

The table of exact transitions for Iranian DST has been extended.
It formerly cut off before the year 2038 in a nod to 32-bit time_t.
It now cuts off before 2091 as there is doubt about how the Persian
calendar will treat 2091. This change predicts DST transitions in
2038-9, 2042-3, and 2046-7 to occur one day later than previously
predicted. As before, post-cutoff transitions are approximated.

Changes to past and future timestamps

Qyzylorda (aka Kyzylorda) oblast in Kazakhstan moved from +06 to
+05 on 2018-12-21. This is a zone split as Qostanay (aka
Kostanay) did not switch, so create a zone Asia/Qostanay.

Metlakatla moved from Alaska to Pacific standard time on 2018-11-04.
It did not change clocks that day and remains on -08 this winter.
(Thanks to Ryan Stanley.) It will revert to the usual Alaska
rules next spring, so this change affects only timestamps
from 2018-11-04 through 2019-03-10.

Change to past timestamps

Kwajalein's 1993-08-20 transition from -12 to +12 was at 24:00,
not 00:00. I transcribed the time incorrectly from Shanks.
(Thanks to Phake Nick.)

Nauru's 1979 transition was on 02-10 at 02:00, not 05-01 at 00:00.
(Thanks to Phake Nick.)

Guam observed DST irregularly from 1959 through 1977.
(Thanks to Phake Nick.)

Hong Kong observed DST in 1941 starting 06-15 (not 04-01), then on
10-01 changed standard time to +08:30 (not +08). Its transition
back to +08 after WWII was on 1945-09-15, not the previous day.
Its 1904-10-30 change took effect at 01:00 +08 (not 00:00 LMT).
(Thanks to Phake Nick, Steve Allen, and Joseph Myers.) Also,
its 1952 fallback was on 11-02 (not 10-25).

This release contains many changes to timestamps before 1946 due
to Japanese possession or occupation of Pacific/Chuuk,
Pacific/Guam, Pacific/Kosrae, Pacific/Kwajalein, Pacific/Majuro,
Pacific/Nauru, Pacific/Palau, and Pacific/Pohnpei.
(Thanks to Phake Nick.)

Assume that the Spanish East Indies was like the Philippines and
observed American time until the end of 1844. This affects
Pacific/Chuuk, Pacific/Kosrae, Pacific/Palau, and Pacific/Pohnpei.

Changes to past tm_isdst flags

For the recent Morocco change, the tm_isdst flag should be 1 from
2018-10-27 00:00 to 2018-10-28 03:00. (Thanks to Michael Deckers.)
Give a URL to the official decree. (Thanks to Matt Johnson.)

show more ...

Update to 2018f:

Changes to code

zic now always generates TZif files where time type 0 is used for
timestamps before the first transition. This simplifies the
reading of TZif files a

Update to 2018f:

Changes to code

zic now always generates TZif files where time type 0 is used for
timestamps before the first transition. This simplifies the
reading of TZif files and should not affect behavior of existing
TZif readers because the same set of time types is used; only
their internal indexes may have changed. This affects only the
legacy zones EST5EDT, CST6CDT, MST7MDT, PST8PDT, CET, MET, and
EET, which previously used nonzero types for these timestamps.

Because of the type 0 change, zic no longer outputs a dummy
transition at time -2**59 (before the Big Bang), as clients should
no longer need this to handle historical timestamps correctly.
This reverts a change introduced in 2013d and shrinks most TZif
files by a few bytes.

zic now supports negative time-of-day in Rule and Leap lines, e.g.,
"Rule X min max - Apr lastSun -6:00 1:00 -" means the transition
occurs at 18:00 on the Saturday before the last Sunday in April.
This behavior was documented in 2018a but the code did not
entirely match the documentation.

localtime.c no longer requires at least one time type in TZif
files that lack transitions or have a POSIX-style TZ string. This
future-proofs the code against possible future extensions to the
format that would allow TZif files with POSIX-style TZ strings and
without transitions or time types.

A read-access subscript error in localtime.c has been fixed.
It could occur only in TZif files with timecnt == 0, something that
does not happen in practice now but could happen in future versions.

localtime.c no longer ignores TZif POSIX-style TZ strings that
specify only standard time. Instead, these TZ strings now
override the default time type for timestamps after the last
transition (or for all time stamps if there are no transitions),
just as DST strings specifying DST have always done.

leapseconds.awk now outputs "#updated" and "#expires" comments,
and supports leap seconds at the ends of months other than June
and December. (Inspired by suggestions from Chris Woodbury.)

Changes to documentation

New restrictions: A Rule name must start with a character that
is neither an ASCII digit nor "-" nor "+", and an unquoted name
should not use characters in the set "!$%&'()*,/:;<=>?@[\]^`{|}~".
The latter restriction makes room for future extensions (a
possibility noted by Tom Lane).

tzfile.5 now documents what time types apply before the first and
after the last transition, if any.

Documentation now uses the spelling "timezone" for a TZ setting
that determines timestamp history, and "time zone" for a
geographic region currently sharing the same standard time.

The name "TZif" is now used for the tz binary data format.

tz-link.htm now mentions the A0 TimeZone Migration utilities.
(Thanks to Aldrin Martoq for the link.)

show more ...

Merge 2018e

Changes to code

zic now accepts subsecond precision in expressions like
00:19:32.13, which is approximately the legal time of the
Netherlands from 1835 to 1937. However,

Merge 2018e

Changes to code

zic now accepts subsecond precision in expressions like
00:19:32.13, which is approximately the legal time of the
Netherlands from 1835 to 1937. However, because it is
questionable whether the few recorded uses of non-integer offsets
had subsecond precision in practice, there are no plans for tzdata
to use this feature. (Thanks to Steve Allen for pointing out
the limitations of historical data in this area.)

The code is a bit more portable to MS-Windows. Installers can
compile with -DRESERVE_STD_EXT_IDS on MS-Windows platforms that
reserve identifiers like 'localtime'. (Thanks to Manuela
Friedrich).

Changes to documentation and commentary

theory.html now outlines tzdb's extensions to POSIX's model for
civil time, and has a section "POSIX features no longer needed"
that lists POSIX API components that are now vestigial.
(From suggestions by Steve Summit.) It also better distinguishes
time zones from tz regions. (From a suggestion by Guy Harris.)

Commentary is now more consistent about using the phrase "daylight
saving time", to match the C name tm_isdst. Daylight saving time
need not occur in summer, and need not have a positive offset from
standard time.

Commentary about historical transitions in Uruguay has been expanded
with links to many relevant legal documents.
(Thanks to Tim Parenti.)

Commentary now uses some non-ASCII characters with Unicode value
less than U+0100, as they can be useful and should work even with
older editors such as XEmacs.

show more ...

Merge tzcode2018c [ changelog with changes to tzdata sections removed ]

Release 2018c - 2018-01-22 23:00:44 -0800

Changes to build procedure

The build procedure now works around mawk 1.3.3's

Merge tzcode2018c [ changelog with changes to tzdata sections removed ]

Release 2018c - 2018-01-22 23:00:44 -0800

Changes to build procedure

The build procedure now works around mawk 1.3.3's lack of support
for character class expressions. (Problem reported by Ohyama.)


Release 2018b - 2018-01-17 23:24:48 -0800

Changes to build procedure

The distribution now contains the file 'pacificnew' again.
This file was inadvertantly omitted in the 2018a distribution.
(Problem reported by Matias Fonzo.)


Release 2018a - 2018-01-12 22:29:21 -0800

Changes to build procedure

The default installation locations have been changed to mostly
match Debian circa 2017, instead of being designed as an add-on to
4.3BSD circa 1986. This affects the Makefile macros TOPDIR,
TZDIR, MANDIR, and LIBDIR. New Makefile macros TZDEFAULT, USRDIR,
USRSHAREDIR, BINDIR, ZDUMPDIR, and ZICDIR let installers tailor
locations more precisely. (This responds to suggestions from
Brian Inglis and from Steve Summit.)

The default installation procedure no longer creates the
backward-compatibility link US/Pacific-New, which causes
confusion during user setup (e.g., see Debian bug 815200).
Use 'make BACKWARD="backward pacificnew"' to create the link
anyway, for now. Eventually we plan to remove the link entirely.

tzdata.zi now contains a version-number comment.
(Suggested by Tom Lane.)

The Makefile now quotes values like BACKWARD more carefully when
passing them to the shell. (Problem reported by Zefram.)

Builders no longer need to specify -DHAVE_SNPRINTF on platforms
that have snprintf and use pre-C99 compilers. (Problem reported
by Jon Skeet.)

Changes to code

zic has a new option -t FILE that specifies the location of the
file that determines local time when TZ is unset. The default for
this location can be configured via the new TZDEFAULT makefile
macro, which defaults to /etc/localtime.

Diagnostics and commentary now distinguish UT from UTC more
carefully; see theory.html for more information about UT vs UTC.

zic has been ported to GCC 8's -Wstringop-truncation option.
(Problem reported by Martin Sebor.)

Changes to documentation and commentary

The zic man page now documents the longstanding behavior that
times and years can be out of the usual range, with negative times
counting backwards from midnight and with year 0 preceding year 1.
(Problem reported by Michael Deckers.)

The theory.html file now mentions the POSIX limit of six chars
per abbreviation, and lists alphabetic abbreviations used.

The files tz-art.htm and tz-link.htm have been renamed to
tz-art.html and tz-link.html, respectively, for consistency with
other file names and to simplify web server configuration.

show more ...

Welcome to 2017c:

zic and the reference runtime now reject multiple leap seconds
within 28 days of each other, or leap seconds before the Epoch.
As a result, support for double leap seco

Welcome to 2017c:

zic and the reference runtime now reject multiple leap seconds
within 28 days of each other, or leap seconds before the Epoch.
As a result, support for double leap seconds, which was
obsolescent and undocumented, has been removed. Double leap
seconds were an error in the C89 standard; they have never existed
in civil timekeeping. (Thanks to Robert Elz and Bradley White for
noticing glitches in the code that uncovered this problem.)

zic now warns about use of the obsolescent and undocumented -y
option, and about use of the obsolescent TYPE field of Rule lines.

zic now allows unambiguous abbreviations like "Sa" and "Su" for
weekdays; formerly it rejected them due to a bug. Conversely, zic
no longer considers non-prefixes to be abbreviations; for example,
it no longer accepts "lF" as an abbreviation for "lastFriday".
Also, zic warns about the undocumented usage with a "last-"
prefix, e.g., "last-Fri".

Similarly, zic now accepts the unambiguous abbreviation "L" for
"Link" in ordinary context and for "Leap" in leap-second context.
Conversely, zic no longer accepts non-prefixes such as "La" as
abbreviations for words like "Leap".

zic no longer accepts leap second lines in ordinary input, or
ordinary lines in leap second input. Formerly, zic sometimes
warned about this undocumented usage and handled it incorrectly.

The new macro HAVE_TZNAME governs whether the tzname external
variable is exported, instead of USG_COMPAT. USG_COMPAT now
governs only the external variables "timezone" and "daylight".
This change is needed because the three variables are not in the
same category: although POSIX requires tzname, it specifies the
other two variables as optional. Also, USG_COMPAT is now 1 or 0:
if not defined, the code attempts to guess it from other macros.

localtime.c and difftime.c no longer require stdio.h, and .c files
other than zic.c no longer require sys/wait.h.

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.)

zic.c no longer mistranslates formats of line numbers in non-English
locales. (Problem reported by Benno Schulenberg.)

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.)

Changes to documentation and commentary

The two new files 'theory.html' and 'calendars' contain the
contents of the removed file 'Theory'. The goal is to document
tzdb theory more accessibly.

The zic man page now documents abbreviation rules.

tz-link.htm now covers how to apply tzdata changes to clients.
(Thanks to Jorge Fábregas for the AIX link.) It also mentions MySQL.

The leap-seconds.list URL has been updated to something that is
more reliable for tzdb. (Thanks to Tim Parenti and Brian Inglis.)

show more ...

merge 2017a

welcome to 2016h

merge tzcode2016g

Sync with 2016b

merge 2015f

merge tzcode2015e:

Changes affecting code

When displaying data, tzselect converts it to the current locale's
encoding if the iconv command works. (Problem reported by random832.)

tz

merge tzcode2015e:

Changes affecting code

When displaying data, tzselect converts it to the current locale's
encoding if the iconv command works. (Problem reported by random832.)

tzselect no longer mishandles Dominica, fixing a bug introduced
in Release 2014f. (Problem reported by Owen Leibman.)

zic -l no longer fails when compiled with -DTZDEFAULT=\"/etc/localtime\".
This fixes a bug introduced in Release 2014f.
(Problem reported by Leonardo Chiquitto.)

show more ...