August 2013 - tz - lists.iana.org

[PATCH 1/2] * .gitignore: Add 'leapseconds'.
by Paul Eggert Aug. 14, 2013

Aug. 14, 2013

This follows up on the previous change, since 'leapseconds' is now generated automatically. --- .gitignore | 1 + 1 file changed, 1 insertion(+) diff --git a/.gitignore b/.gitignore index 5edf101..21c798d 100644 --- a/.gitignore +++ b/.gitignore @@ -4,6 +4,7 @@ *.txt *~ ChangeLog +leapseconds tzselect version.h yearistype -- 1.7.11.7

1 1

Re: [tz] Proposal regarding tz DB and leap second updates
by Paul Eggert Aug. 13, 2013

Aug. 13, 2013

Bradley White privately sent a Perl script to generate 'leapseconds' from the NIST leap-seconds.list file. Since we use POSIX Awk for the other processing it's probably better to use Awk here, too, so here's a proposed patch with all the Makefile bells and whistles, which I pushed to the experimental github repository. The patch removes the file 'leapseconds' from the repository because it's now generated automatically. I took the liberty of removing the copy of the IERS announcement from the generated 'leapseconds' since its copyright status was unclear. The NIST leap-seconds.list file is public domain, so it's OK for us to redistribute it. >From 459b72d3edec98488e5132d4473c4678b4ed5a73 Mon Sep 17 00:00:00 2001 From: Paul Eggert <eggert(a)cs.ucla.edu> Date: Mon, 12 Aug 2013 23:58:29 -0700 Subject: [PATCH] Generate the 'leapseconds' file automatically from leap-seconds.list. * leap-seconds.list: New file, copied from the NIST. * leapseconds: Remove from git; it's now generated. * leapseconds.awk: New file. * Makefile (DATA): Add leap-seconds.list. Remove leapseconds. (MISC): Add leapseconds.awk. (leapseconds): New rule. (right_posix, posix_right): Depend on leapseconds. (clean_misc): Remove leapseconds. --- Makefile | 14 ++-- leap-seconds.list | 231 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ leapseconds | 100 ----------------------- leapseconds.awk | 68 ++++++++++++++++ 4 files changed, 308 insertions(+), 105 deletions(-) create mode 100644 leap-seconds.list delete mode 100644 leapseconds create mode 100644 leapseconds.awk diff --git a/Makefile b/Makefile index db7f56e..68d7132 100644 --- a/Makefile +++ b/Makefile @@ -318,10 +318,11 @@ NDATA= systemv factory SDATA= solar87 solar88 solar89 TDATA= $(YDATA) $(NDATA) $(SDATA) TABDATA= iso3166.tab zone.tab -DATA= $(YDATA) $(NDATA) $(SDATA) $(TABDATA) leapseconds yearistype.sh +DATA= $(YDATA) $(NDATA) $(SDATA) $(TABDATA) \ + leap-seconds.list yearistype.sh WEB_PAGES= tz-art.htm tz-link.htm MISC= usno1988 usno1989 usno1989a usno1995 usno1997 usno1998 \ - $(WEB_PAGES) checktab.awk workman.sh \ + $(WEB_PAGES) checktab.awk leapseconds.awk workman.sh \ zoneinfo2tdf.pl ENCHILADA= $(COMMON) $(DOCS) $(SOURCES) $(DATA) $(MISC) @@ -375,6 +376,9 @@ yearistype: yearistype.sh cp yearistype.sh yearistype chmod +x yearistype +leapseconds: leapseconds.awk leap-seconds.list + $(AWK) -f leapseconds.awk leap-seconds.list >$@ + posix_only: zic $(TDATA) $(ZIC) -y $(YEARISTYPE) -d $(TZDIR) -L /dev/null $(TDATA) @@ -390,14 +394,14 @@ right_only: zic leapseconds $(TDATA) # Therefore, the other two directories are now siblings of $(TZDIR). # You must replace all of $(TZDIR) to switch from not using leap seconds # to using them, or vice versa. -right_posix: right_only +right_posix: right_only leapseconds rm -fr $(TZDIR)-leaps ln -s $(TZDIR_BASENAME) $(TZDIR)-leaps || \ $(ZIC) -y $(YEARISTYPE) \ -d $(TZDIR)-leaps -L leapseconds $(TDATA) $(ZIC) -y $(YEARISTYPE) -d $(TZDIR)-posix -L /dev/null $(TDATA) -posix_right: posix_only +posix_right: posix_only leapseconds rm -fr $(TZDIR)-posix ln -s $(TZDIR_BASENAME) $(TZDIR)-posix || \ $(ZIC) -y $(YEARISTYPE) \ @@ -440,7 +444,7 @@ check_web: $(WEB_PAGES) clean_misc: rm -f core *.o *.out \ - date tzselect version.h zdump zic yearistype + date leapseconds tzselect version.h zdump zic yearistype clean: clean_misc rm -f -r tzpublic diff --git a/leap-seconds.list b/leap-seconds.list new file mode 100644 index 0000000..7df3de6 --- /dev/null +++ b/leap-seconds.list @@ -0,0 +1,231 @@ +# +# In the following text, the symbol '#' introduces +# a comment, which continues from that symbol until +# the end of the line. A plain comment line has a +# whitespace character following the comment indicator. +# There are also special comment lines defined below. +# A special comment will always have a non-whitespace +# character in column 2. +# +# A blank line should be ignored. +# +# The following table shows the corrections that must +# be applied to compute International Atomic Time (TAI) +# from the Coordinated Universal Time (UTC) values that +# are transmitted by almost all time services. +# +# The first column shows an epoch as a number of seconds +# since 1900.0 and the second column shows the number of +# seconds that must be added to UTC to compute TAI for +# any timestamp at or after that epoch. The value on +# each line is valid from the indicated initial instant +# until the epoch given on the next one or indefinitely +# into the future if there is no next line. +# (The comment on each line shows the representation of +# the corresponding initial epoch in the usual +# day-month-year format. The epoch always begins at +# 00:00:00 UTC on the indicated day. See Note 5 below.) +# +# Important notes: +# +# 1. Coordinated Universal Time (UTC) is often referred to +# as Greenwich Mean Time (GMT). The GMT time scale is no +# longer used, and the use of GMT to designate UTC is +# discouraged. +# +# 2. The UTC time scale is realized by many national +# laboratories and timing centers. Each laboratory +# identifies its realization with its name: Thus +# UTC(NIST), UTC(USNO), etc. The differences among +# these different realizations are typically on the +# order of a few nanoseconds (i.e., 0.000 000 00x s) +# and can be ignored for many purposes. These differences +# are tabulated in Circular T, which is published monthly +# by the International Bureau of Weights and Measures +# (BIPM). See www.bipm.fr for more information. +# +# 3. The current defintion of the relationship between UTC +# and TAI dates from 1 January 1972. A number of different +# time scales were in use before than epoch, and it can be +# quite difficult to compute precise timestamps and time +# intervals in those "prehistoric" days. For more information, +# consult: +# +# The Explanatory Supplement to the Astronomical +# Ephemeris. +# or +# Terry Quinn, "The BIPM and the Accurate Measurement +# of Time," Proc. of the IEEE, Vol. 79, pp. 894-905, +# July, 1991. +# +# 4. The insertion of leap seconds into UTC is currently the +# responsibility of the International Earth Rotation Service, +# which is located at the Paris Observatory: +# +# Central Bureau of IERS +# 61, Avenue de l'Observatoire +# 75014 Paris, France. +# +# Leap seconds are announced by the IERS in its Bulletin C +# +# See hpiers.obspm.fr or www.iers.org for more details. +# +# All national laboratories and timing centers use the +# data from the BIPM and the IERS to construct their +# local realizations of UTC. +# +# Although the definition also includes the possibility +# of dropping seconds ("negative" leap seconds), this has +# never been done and is unlikely to be necessary in the +# foreseeable future. +# +# 5. If your system keeps time as the number of seconds since +# some epoch (e.g., NTP timestamps), then the algorithm for +# assigning a UTC time stamp to an event that happens during a positive +# leap second is not well defined. The official name of that leap +# second is 23:59:60, but there is no way of representing that time +# in these systems. +# Many systems of this type effectively stop the system clock for +# one second during the leap second and use a time that is equivalent +# to 23:59:59 UTC twice. For these systems, the corresponding TAI +# timestamp would be obtained by advancing to the next entry in the +# following table when the time equivalent to 23:59:59 UTC +# is used for the second time. Thus the leap second which +# occurred on 30 June 1972 at 23:59:59 UTC would have TAI +# timestamps computed as follows: +# +# ... +# 30 June 1972 23:59:59 (2287785599, first time): TAI= UTC + 10 seconds +# 30 June 1972 23:59:60 (2287785599,second time): TAI= UTC + 11 seconds +# 1 July 1972 00:00:00 (2287785600) TAI= UTC + 11 seconds +# ... +# +# If your system realizes the leap second by repeating 00:00:00 UTC twice +# (this is possible but not usual), then the advance to the next entry +# in the table must occur the second time that a time equivlent to +# 00:00:00 UTC is used. Thus, using the same example as above: +# +# ... +# 30 June 1972 23:59:59 (2287785599): TAI= UTC + 10 seconds +# 30 June 1972 23:59:60 (2287785600, first time): TAI= UTC + 10 seconds +# 1 July 1972 00:00:00 (2287785600,second time): TAI= UTC + 11 seconds +# ... +# +# in both cases the use of timestamps based on TAI produces a smooth +# time scale with no discontinuity in the time interval. +# +# This complexity would not be needed for negative leap seconds (if they +# are ever used). The UTC time would skip 23:59:59 and advance from +# 23:59:58 to 00:00:00 in that case. The TAI offset would decrease by +# 1 second at the same instant. This is a much easier situation to deal +# with, since the difficulty of unambiguously representing the epoch +# during the leap second does not arise. +# +# Questions or comments to: +# Judah Levine +# Time and Frequency Division +# NIST +# Boulder, Colorado +# jlevine(a)boulder.nist.gov +# +# Last Update of leap second values: 11 January 2012 +# +# The following line shows this last update date in NTP timestamp +# format. This is the date on which the most recent change to +# the leap second data was added to the file. This line can +# be identified by the unique pair of characters in the first two +# columns as shown below. +# +#$ 3535228800 +# +# The NTP timestamps are in units of seconds since the NTP epoch, +# which is 1900.0. The Modified Julian Day number corresponding +# to the NTP time stamp, X, can be computed as +# +# X/86400 + 15020 +# +# where the first term converts seconds to days and the second +# term adds the MJD corresponding to 1900.0. The integer portion +# of the result is the integer MJD for that day, and any remainder +# is the time of day, expressed as the fraction of the day since 0 +# hours UTC. The conversion from day fraction to seconds or to +# hours, minutes, and seconds may involve rounding or truncation, +# depending on the method used in the computation. +# +# The data in this file will be updated periodically as new leap +# seconds are announced. In addition to being entered on the line +# above, the update time (in NTP format) will be added to the basic +# file name leap-seconds to form the name leap-seconds.<NTP TIME>. +# In addition, the generic name leap-seconds.list will always point to +# the most recent version of the file. +# +# This update procedure will be performed only when a new leap second +# is announced. +# +# The following entry specifies the expiration date of the data +# in this file in units of seconds since 1900.0. This expiration date +# will be changed at least twice per year whether or not a new leap +# second is announced. These semi-annual changes will be made no +# later than 1 June and 1 December of each year to indicate what +# action (if any) is to be taken on 30 June and 31 December, +# respectively. (These are the customary effective dates for new +# leap seconds.) This expiration date will be identified by a +# unique pair of characters in columns 1 and 2 as shown below. +# In the unlikely event that a leap second is announced with an +# effective date other than 30 June or 31 December, then this +# file will be edited to include that leap second as soon as it is +# announced or at least one month before the effective date +# (whichever is later). +# If an announcement by the IERS specifies that no leap second is +# scheduled, then only the expiration date of the file will +# be advanced to show that the information in the file is still +# current -- the update time stamp, the data and the name of the file +# will not change. +# +# Updated through IERS Bulletin C46 +# File expires on: 28 June 2014 +# +#@ 3612902400 +# +2272060800 10 # 1 Jan 1972 +2287785600 11 # 1 Jul 1972 +2303683200 12 # 1 Jan 1973 +2335219200 13 # 1 Jan 1974 +2366755200 14 # 1 Jan 1975 +2398291200 15 # 1 Jan 1976 +2429913600 16 # 1 Jan 1977 +2461449600 17 # 1 Jan 1978 +2492985600 18 # 1 Jan 1979 +2524521600 19 # 1 Jan 1980 +2571782400 20 # 1 Jul 1981 +2603318400 21 # 1 Jul 1982 +2634854400 22 # 1 Jul 1983 +2698012800 23 # 1 Jul 1985 +2776982400 24 # 1 Jan 1988 +2840140800 25 # 1 Jan 1990 +2871676800 26 # 1 Jan 1991 +2918937600 27 # 1 Jul 1992 +2950473600 28 # 1 Jul 1993 +2982009600 29 # 1 Jul 1994 +3029443200 30 # 1 Jan 1996 +3076704000 31 # 1 Jul 1997 +3124137600 32 # 1 Jan 1999 +3345062400 33 # 1 Jan 2006 +3439756800 34 # 1 Jan 2009 +3550089600 35 # 1 Jul 2012 +# +# the following special comment contains the +# hash value of the data in this file computed +# use the secure hash algorithm as specified +# by FIPS 180-1. See the files in ~/pub/sha for +# the details of how this hash value is +# computed. Note that the hash computation +# ignores comments and whitespace characters +# in data lines. It includes the NTP values +# of both the last modification time and the +# expiration time of the file, but not the +# white space on those lines. +# the hash line is also ignored in the +# computation. +# +#h 1151a8f e85a5069 9000fcdb 3d5e5365 1d505b37 diff --git a/leapseconds b/leapseconds deleted file mode 100644 index 5b5c70e..0000000 --- a/leapseconds +++ /dev/null @@ -1,100 +0,0 @@ -# <pre> -# This file is in the public domain, so clarified as of -# 2009-05-17 by Arthur David Olson. - -# Allowance for leapseconds added to each timezone file. - -# The International Earth Rotation Service periodically uses leap seconds -# to keep UTC to within 0.9 s of UT1 -# (which measures the true angular orientation of the earth in space); see -# Terry J Quinn, The BIPM and the accurate measure of time, -# Proc IEEE 79, 7 (July 1991), 894-905. -# There were no leap seconds before 1972, because the official mechanism -# accounting for the discrepancy between atomic time and the earth's rotation -# did not exist until the early 1970s. - -# The correction (+ or -) is made at the given time, so lines -# will typically look like: -# Leap YEAR MON DAY 23:59:60 + R/S -# or -# Leap YEAR MON DAY 23:59:59 - R/S - -# If the leapsecond is Rolling (R) the given time is local time -# If the leapsecond is Stationary (S) the given time is UTC - -# Leap YEAR MONTH DAY HH:MM:SS CORR R/S -Leap 1972 Jun 30 23:59:60 + S -Leap 1972 Dec 31 23:59:60 + S -Leap 1973 Dec 31 23:59:60 + S -Leap 1974 Dec 31 23:59:60 + S -Leap 1975 Dec 31 23:59:60 + S -Leap 1976 Dec 31 23:59:60 + S -Leap 1977 Dec 31 23:59:60 + S -Leap 1978 Dec 31 23:59:60 + S -Leap 1979 Dec 31 23:59:60 + S -Leap 1981 Jun 30 23:59:60 + S -Leap 1982 Jun 30 23:59:60 + S -Leap 1983 Jun 30 23:59:60 + S -Leap 1985 Jun 30 23:59:60 + S -Leap 1987 Dec 31 23:59:60 + S -Leap 1989 Dec 31 23:59:60 + S -Leap 1990 Dec 31 23:59:60 + S -Leap 1992 Jun 30 23:59:60 + S -Leap 1993 Jun 30 23:59:60 + S -Leap 1994 Jun 30 23:59:60 + S -Leap 1995 Dec 31 23:59:60 + S -Leap 1997 Jun 30 23:59:60 + S -Leap 1998 Dec 31 23:59:60 + S -Leap 2005 Dec 31 23:59:60 + S -Leap 2008 Dec 31 23:59:60 + S -Leap 2012 Jun 30 23:59:60 + S - -# INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) -# -# SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE -# -# -# SERVICE DE LA ROTATION TERRESTRE -# OBSERVATOIRE DE PARIS -# 61, Av. de l'Observatoire 75014 PARIS (France) -# Tel. : 33 (0) 1 40 51 22 26 -# FAX : 33 (0) 1 40 51 22 91 -# e-mail : (E-Mail Removed) -# http://hpiers.obspm.fr/eop-pc -# -# Paris, 5 January 2012 -# -# -# Bulletin C 43 -# -# To authorities responsible -# for the measurement and -# distribution of time -# -# -# UTC TIME STEP -# on the 1st of July 2012 -# -# -# A positive leap second will be introduced at the end of June 2012. -# The sequence of dates of the UTC second markers will be: -# -# 2012 June 30, 23h 59m 59s -# 2012 June 30, 23h 59m 60s -# 2012 July 1, 0h 0m 0s -# -# The difference between UTC and the International Atomic Time TAI is: -# -# from 2009 January 1, 0h UTC, to 2012 July 1 0h UTC : UTC-TAI = - 34s -# from 2012 July 1, 0h UTC, until further notice : UTC-TAI = - 35s -# -# 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. -# -# -# Daniel GAMBIS -# Head -# Earth Orientation Center of IERS -# Observatoire de Paris, France diff --git a/leapseconds.awk b/leapseconds.awk new file mode 100644 index 0000000..732db99 --- /dev/null +++ b/leapseconds.awk @@ -0,0 +1,68 @@ +# Generate the 'leapseconds' file from 'leap-seconds.list'. + +# This file is in the public domain. + +BEGIN { + printf "%s", "\ +# Allowance for leapseconds added to each timezone file.\n\ +\n\ +# This file is in the public domain.\n\ +\n\ +# This file is generated automatically from the data in the public-domain\n\ +# leap-seconds.list file available from most NIST time servers.\n\ +# If the URL <ftp://time.nist.gov/pub/leap-seconds.list> does not work,\n\ +# you should be able to pick up leap-seconds.list from a secondary NIST server.\n\ +# For more about leap-seconds.list, please see\n\ +# The NTP Timescale and Leap Seconds\n\ +# <http://www.eecis.udel.edu/~mills/leap.html>.\n\ +\n\ +# The International Earth Rotation Service periodically uses leap seconds\n\ +# to keep UTC to within 0.9 s of UT1\n\ +# (which measures the true angular orientation of the earth in space); see\n\ +# Terry J Quinn, The BIPM and the accurate measure of time,\n\ +# Proc IEEE 79, 7 (July 1991), 894-905 <http://dx.doi.org/10.1109/5.84965>.\n\ +# There were no leap seconds before 1972, because the official mechanism\n\ +# accounting for the discrepancy between atomic time and the earth's rotation\n\ +# did not exist until the early 1970s.\n\ +\n\ +# The correction (+ or -) is made at the given time, so lines\n\ +# will typically look like:\n\ +# Leap YEAR MON DAY 23:59:60 + R/S\n\ +# or\n\ +# Leap YEAR MON DAY 23:59:59 - R/S\n\ +\n\ +# If the leapsecond is Rolling (R) the given time is local time.\n\ +# If the leapsecond is Stationary (S) the given time is UTC.\n\ +\n\ +# Leap YEAR MONTH DAY HH:MM:SS CORR R/S\n\ +" +} + +/^ *$/ { next } +/^#/ { next } + +{ + NTP_timestamp = $1 + TAI_minus_UTC = $2 + hash_mark = $3 + one = $4 + month = $5 + year = $6 + if (old_TAI_minus_UTC) { + if (old_TAI_minus_UTC < TAI_minus_UTC) { + sign = "23:59:60\t+" + } else { + sign = "23:59:59\t-" + } + if (month == "Jan") { + year--; + month = "Dec"; + day = 31 + } else if (month == "Jul") { + month = "Jun"; + day = 30 + } + printf "Leap\t%s\t%s\t%s\t%s\tS\n", year, month, day, sign + } + old_TAI_minus_UTC = TAI_minus_UTC +} -- 1.8.1.2

2 1

Proposal regarding tz DB and leap second updates
by Martin Burnicki Aug. 13, 2013

Aug. 13, 2013

Hi everybody, here are some thoughts about ways to make timekeeping simpler, especially with regards to DST, and leap seconds. Some time ago there was a discussion on the tz mailing list about frequently changing DST dates in Morocco, and that the Moroc government determines the beginning and end of DST only a very short period before the changes are to come into effect. A major problem is the short time period admins have available to deploy tz data base updates to machines in a mixed environment e.g. consisting of several Unix flavors, and Windows systems. I know Windows systems don't use the tz DB directly, but unlike older Windows version which could only provide DST information for the current year, current Windows version can at least provide DST settings for several years in their registry, and I could imagine some MS engineer has written a script which generates those registry settings from the tz DB. ;-) Updates of those registry settings are usually deployed as Windows patches. AFAIK even for Unix systems the tz DB updates are usually deployed as software updates, e.g. updated .rpm or .deb packages for Linux. So whenever there's a change in the DST specs for some country, a server admin responsible for different types of machines has to wait until all manufacturers or distributors of all the OS types and versions he is running on his machines have become aware of a tz DB update, and have provided software update packages for all their systems, before all machines can be updated consistently, each system type using its own update procedure. This may not be a big deal for users in the United States, or in Europe, where DST rules are changing only very rarely. If you don't install tz database updates then there's a good chance everything keeps working fine since no DST rules have changed. However, for people in Morocco, or Israel, or some other countries it seems to be quite a challenge to keep everything up to date, if there are changes once every year. We at Meinberg are manufacturing NTP time servers, and there are often requests from customers to use NTP to send local time to the clients. Of course this is no reliable solution and caused many sorts of other problems which are not obvious at the first glance. However, this shows the importance for a way to simplify tz DB updates. My proposal is to use some sort of network protocol to deploy the contents of the tz DB, either for a single time zone used on a system, or even for all time zones supported by the tz database. In my opinion this is similar to DNS or DHCP, or even NTP services. So a machine could simply run a TZ client daemon which periodically contacts a TZ server to check if there is an update available, and download the updated data if this is the case. A mechanism like the serial numbers used for DNS zone transfers could be used to do this. Of course the tz information must be deployed in a secure way, but this is a common requirement for all kind of network services today, using crypto mechanisms, etc. This would also simplify the update of tz data in embedded systems which often don't see any software updates anymore after they have been put into operation. Another important thing which could be implemented in the same protocol is handling of leap second information. I don't want to restart the discussion whether leap seconds are useful and required, or not, but the following suggestions can help to simplify handling of future leap seconds, if they should occur, and they don't hurt but help to handle historic leap seconds, if required to evaluate archived data, etc. Actually the NIST provides a leap second file providing current and historic leap second information. This file can directly be handled and evaluated by the standard NTP daemon. There are plans to implement this also in the open source PTP daemon, since PTP by default uses TAI for the timestamps in the network packets, and a leap second file is a good resource to convert between TAI and UTC. I know the tz DB also includes a leap second file, which is used for the "right" timezones. As far as I know this file provides similar information as the NIST file but has a slightly different format. My proposal is to change the TZ code and DB in a first step so that they also use the NIST leap second file format. I'm not aware of any operating system which uses the "right" timezones by default now, but as far as I can see such modification can be done consistently and transparently for the users, since both the tz code and the file can be updated consistently. So there should be no problems for folks who use the "right" timezones. Many types of hardware refclocks used to set up stratum-1 NTP servers don't provide the NTP daemon with leap second warnings, so those NTP servers often have to rely on a leap second file which needs to be updated if a leap second has been scheduled. Usually there are about 6 months time to do so. Also future versions of the PTP daemon will have this requirement. So if the same leap second file format was used for all applications then the same file could be shared, and for now, it could be updated within any tz database update. If in the future there should be a network protocol which could be used to deploy tz updates, then the same protocol could also be used to update the leap second file, if required, and life could become much easier for many admins. ;-) Any comments are welcome. [I'm also going to send this to the leapsecond mailing list, even though some folks may be subscribed on both lists] Martin -- Martin Burnicki Meinberg Funkuhren Bad Pyrmont Germany

6 5

[PATCH] Remove attempt to support floating-point time_t.
by Paul Eggert Aug. 12, 2013

Aug. 12, 2013

Here's a proposed patch to remove the tz code's attempt to support floating-point time_t. This has the benefit of simplifying the code and making maintenance easier. Comments welcome (particularly if you know of any real systems that have floating-point time_t!). I've pushed this to the experimental github repository. ----- It wasn't tested and probably never worked, no platform used it, and the latest POSIX no longer allows it. * Makefile (typecheck): Don't check time_t being 'double'. * Theory: Document the change. * difftime.c (difftime): * localtime.c (differ_by_repeat, tzload, timesub, time2sub): * private.h (time_t_min, time_t_max): * zdump.c (absolute_min_time, absolute_max_time, tformat): Don't try to support floating-point time_t. * localtime.c, private.h, zdump.c: Don't include float.h. * localtime.c (truncate_time, double_to_time): * private.h (TYPE_INTEGRAL): * zdump.c (checkabsolutes): Remove; no longer needed. All uses removed. * zdump.8 (LIMITATIONS): Remove discussion of floating-point time_t. --- Makefile | 3 +-- Theory | 9 ++++----- difftime.c | 10 +--------- localtime.c | 62 ++++++------------------------------------------------------- private.h | 28 ++-------------------------- zdump.8 | 7 ------- zdump.c | 37 ++---------------------------------- 7 files changed, 16 insertions(+), 140 deletions(-) diff --git a/Makefile b/Makefile index 8b033a6..db7f56e 100644 --- a/Makefile +++ b/Makefile @@ -121,7 +121,6 @@ LDLIBS= # -DNO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU=1 # if you do not want run time warnings about formats that may cause # year 2000 grief -# -DTIME_T_FLOATING=1 if your time_t (or time_tz) is floating point # -Dtime_tz=\"T\" to use T as the time_t type, rather than the system time_t # -DTZ_DOMAIN=\"foo\" to use "foo" for gettext domain name; default is "tz" # -TTZ_DOMAINDIR=\"/path\" to use "/path" for gettext directory; @@ -541,7 +540,7 @@ tzdata$(VERSION).tar.gz.asc: tzdata$(VERSION).tar.gz typecheck: make clean - for i in "long long" unsigned double; \ + for i in "long long" unsigned; \ do \ make CFLAGS="-DTYPECHECK -D__time_t_defined -D_TIME_T \"-Dtime_t=$$i\"" ; \ ./zdump -v Europe/Rome ; \ diff --git a/Theory b/Theory index 1b5374a..b4bd4c2 100644 --- a/Theory +++ b/Theory @@ -104,11 +104,10 @@ POSIX has the following properties and limitations. new implementations these days typically use a signed 64-bit integer. Unsigned 32-bit integers are used on one or two platforms, and 36-bit integers are also used occasionally. - Although POSIX.1-2013 requires time_t to be an integer type, - earlier POSIX versions also allowed time_t to be a floating-point type. - No known platforms have a floating-point time_t and although - the tz code attempts to support floating-point time_t this has not - been tested and will probably be removed at some point. + Although earlier POSIX versions allowed time_t to be a + floating-point type, this was not supported by any practical + systems, and POSIX.1-2013 and the tz code both require time_t + to be an integer type. These are the extensions that have been made to the POSIX functions: diff --git a/difftime.c b/difftime.c index fcd18ce..449cdf0 100644 --- a/difftime.c +++ b/difftime.c @@ -5,7 +5,7 @@ /*LINTLIBRARY*/ -#include "private.h" /* for time_t, TYPE_INTEGRAL, and TYPE_SIGNED */ +#include "private.h" /* for time_t and TYPE_SIGNED */ double ATTRIBUTE_CONST difftime(const time_t time1, const time_t time0) @@ -16,15 +16,8 @@ difftime(const time_t time1, const time_t time0) */ if (sizeof (double) > sizeof (time_t)) return (double) time1 - (double) time0; - if (!TYPE_INTEGRAL(time_t)) { - /* - ** time_t is floating. - */ - return time1 - time0; - } if (!TYPE_SIGNED(time_t)) { /* - ** time_t is integral and unsigned. ** The difference of two unsigned values can't overflow ** if the minuend is greater than or equal to the subtrahend. */ @@ -33,7 +26,6 @@ difftime(const time_t time1, const time_t time0) else return -(double) (time0 - time1); } /* - ** time_t is integral and signed. ** Handle cases where both time1 and time0 have the same sign ** (meaning that their difference cannot overflow). */ diff --git a/localtime.c b/localtime.c index 9600901..5312ad9 100644 --- a/localtime.c +++ b/localtime.c @@ -13,7 +13,6 @@ #include "private.h" #include "tzfile.h" #include "fcntl.h" -#include "float.h" /* for FLT_MAX and DBL_MAX */ #ifndef TZ_ABBR_MAX_LEN #define TZ_ABBR_MAX_LEN 16 @@ -318,9 +317,8 @@ settzname(void) static int differ_by_repeat(const time_t t1, const time_t t0) { - if (TYPE_INTEGRAL(time_t) && - TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS) - return 0; + if (TYPE_BIT(time_t) - TYPE_SIGNED(time_t) < SECSPERREPEAT_BITS) + return 0; return t1 - t0 == SECSPERREPEAT; } @@ -527,9 +525,9 @@ tzload(register const char *name, register struct state *const sp, for (i = 0; i < nread; ++i) up->buf[i] = p[i]; /* - ** If this is a narrow integer time_t system, we're done. + ** If this is a narrow time_t system, we're done. */ - if (stored >= (int) sizeof(time_t) && TYPE_INTEGRAL(time_t)) + if (stored >= (int) sizeof(time_t)) break; } if (doextend && nread > 2 && @@ -1254,35 +1252,6 @@ tzset(void) settzname(); } -/* Return T with any fractional part discarded. */ -static time_t -truncate_time(time_t t) -{ - /* - ** If time_t is floating-point, convert it to integer and - ** back; this discards the fraction. Avoid using <math.h> - ** functions, as we don't want to depend on <math.h>. Use <, - ** not <=, when comparing against *_MIN and *_MAX values, as - ** this avoids undefined behavior when, for example, - ** INTMAX_MAX is converted to a larger time_t value before it - ** is compared. - ** - ** On all platforms that we know of (1) it is safe to compare - ** INTMAX_MIN and INTMAX_MAX to floating-point values without - ** worrying about undefined behavior due to floating-point - ** overflow on conversion, and (2) any time_t value outside - ** intmax_t range is an integer so we can simply return it. - ** We know of no simple, portable way to check these assumptions. - ** If you know of a counterexample platform, please report a bug. - */ - if (!TYPE_INTEGRAL(time_t) && INTMAX_MIN < t && t < INTMAX_MAX) { - intmax_t i = t; - return i; - } - - return t; -} - /* ** The easy way to behave "as if no library function calls" localtime ** is to not call it--so we drop its guts into "localsub", which can be @@ -1318,8 +1287,7 @@ localsub(const time_t *const timep, const int_fast32_t offset, seconds = sp->ats[0] - t; else seconds = t - sp->ats[sp->timecnt - 1]; --seconds; - years = (truncate_time (seconds / SECSPERREPEAT + 1) - * YEARSPERREPEAT); + years = (seconds / SECSPERREPEAT + 1) * YEARSPERREPEAT; seconds = years * AVGSECSPERYEAR; if (t < sp->ats[0]) newt += seconds; @@ -1457,18 +1425,6 @@ offtime(const time_t *const timep, const long offset) #endif /* defined STD_INSPIRED */ /* -** Convert T to time_t, truncating toward zero if time_t is integral. -** On most platforms, double_to_time(0.5) returns 0; the exceptions are -** the rare platforms where time_t is floating. -*/ - -static time_t -double_to_time(double t) -{ - return t; -} - -/* ** Return the number of leap years through the end of the given year ** where, to make the math easy, the answer for year zero is defined as zero. */ @@ -1549,9 +1505,8 @@ timesub(const time_t *const timep, const int_fast32_t offset, } { register int_fast32_t seconds; - register time_t half_second = double_to_time(0.5); - seconds = tdays * SECSPERDAY + half_second; + seconds = tdays * SECSPERDAY; tdays = seconds / SECSPERDAY; rem += seconds - tdays * SECSPERDAY; } @@ -1811,11 +1766,6 @@ time2sub(struct tm *const tmp, if (!TYPE_SIGNED(time_t)) { lo = 0; hi = lo - 1; - } else if (!TYPE_INTEGRAL(time_t)) { - if (sizeof(time_t) > sizeof(float)) - hi = (time_t) DBL_MAX; - else hi = (time_t) FLT_MAX; - lo = -hi; } else { lo = 1; for (i = 0; i < (int) TYPE_BIT(time_t) - 1; ++i) diff --git a/private.h b/private.h index 5f4384e..8c1cda7 100644 --- a/private.h +++ b/private.h @@ -74,7 +74,6 @@ #include "sys/types.h" /* for time_t */ #include "stdio.h" #include "errno.h" -#include "float.h" /* for FLT_MAX and DBL_MAX */ #include "string.h" #include "limits.h" /* for CHAR_BIT et al. */ #include "time.h" @@ -318,37 +317,14 @@ const char * scheck(const char * string, const char * format); /* The minimum and maximum finite time values. */ static time_t const time_t_min = - ((time_t) 0.5 == 0.5 - ? (sizeof (time_t) == sizeof (float) ? (time_t) -FLT_MAX - : sizeof (time_t) == sizeof (double) ? (time_t) -DBL_MAX - : sizeof (time_t) == sizeof (long double) ? (time_t) -LDBL_MAX - : 0) -#ifndef TIME_T_FLOATING - : (time_t) -1 < 0 + (TYPE_SIGNED(time_t) ? (time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1) -#endif : 0); static time_t const time_t_max = - ((time_t) 0.5 == 0.5 - ? (sizeof (time_t) == sizeof (float) ? (time_t) FLT_MAX - : sizeof (time_t) == sizeof (double) ? (time_t) DBL_MAX - : sizeof (time_t) == sizeof (long double) ? (time_t) LDBL_MAX - : -1) -#ifndef TIME_T_FLOATING - : (time_t) -1 < 0 + (TYPE_SIGNED(time_t) ? - (~ 0 < 0) - ((time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1)) -#endif : -1); -/* -** Since the definition of TYPE_INTEGRAL contains floating point numbers, -** it cannot be used in preprocessor directives. -*/ - -#ifndef TYPE_INTEGRAL -#define TYPE_INTEGRAL(type) (((type) 0.5) != 0.5) -#endif /* !defined TYPE_INTEGRAL */ - #ifndef INT_STRLEN_MAXIMUM /* ** 302 / 1000 is log10(2.0) rounded up. diff --git a/zdump.8 b/zdump.8 index f253e81..af3277d 100644 --- a/zdump.8 +++ b/zdump.8 @@ -57,13 +57,6 @@ the program cuts off verbose output near the starts of the years \-500 and 2500. Cut off verbose output at the start of the given time(s), given in decimal seconds since 1970-01-01 00:00:00 UTC. .SH LIMITATIONS -The -.B \-v -and -.B \-V -options may not be used on systems with floating-point time_t values -that are neither float nor double. -.PP Time discontinuities are found by sampling the results returned by localtime at twelve-hour intervals. This works in all real-world cases; diff --git a/zdump.c b/zdump.c index be0a496..788020a 100644 --- a/zdump.c +++ b/zdump.c @@ -23,7 +23,6 @@ #include "sys/types.h" /* for time_t */ #include "time.h" /* for struct tm */ #include "stdlib.h" /* for exit, malloc, atoi */ -#include "float.h" /* for FLT_MAX and DBL_MAX */ #include "limits.h" /* for CHAR_BIT, LLONG_MAX */ #include "ctype.h" /* for isalpha et al. */ #ifndef isascii @@ -193,26 +192,12 @@ extern char * tzname[2]; /* The minimum and maximum finite time values. */ static time_t const absolute_min_time = - ((time_t) 0.5 == 0.5 - ? (sizeof (time_t) == sizeof (float) ? (time_t) -FLT_MAX - : sizeof (time_t) == sizeof (double) ? (time_t) -DBL_MAX - : sizeof (time_t) == sizeof (long double) ? (time_t) -LDBL_MAX - : 0) -#ifndef TIME_T_FLOATING - : (time_t) -1 < 0 + ((time_t) -1 < 0 ? (time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1) -#endif : 0); static time_t const absolute_max_time = - ((time_t) 0.5 == 0.5 - ? (sizeof (time_t) == sizeof (float) ? (time_t) FLT_MAX - : sizeof (time_t) == sizeof (double) ? (time_t) DBL_MAX - : sizeof (time_t) == sizeof (long double) ? (time_t) LDBL_MAX - : -1) -#ifndef TIME_T_FLOATING - : (time_t) -1 < 0 + ((time_t) -1 < 0 ? - (~ 0 < 0) - ((time_t) -1 << (CHAR_BIT * sizeof (time_t) - 1)) -#endif : -1); static size_t longest; static char * progname; @@ -223,7 +208,6 @@ static void abbrok(const char * abbrp, const char * zone); static intmax_t delta(struct tm * newp, struct tm * oldp) ATTRIBUTE_PURE; static void dumptime(const struct tm * tmp); static time_t hunt(char * name, time_t lot, time_t hit); -static void checkabsolutes(void); static void show(char * zone, time_t t, int v); static const char * tformat(void); static time_t yeartot(intmax_t y) ATTRIBUTE_PURE; @@ -383,7 +367,6 @@ main(int argc, char *argv[]) exit(EXIT_FAILURE); } } - checkabsolutes(); if (cutarg != NULL || cuttimes == NULL) { cutlotime = yeartot(cutloyear); cuthitime = yeartot(cuthiyear); @@ -504,17 +487,6 @@ main(int argc, char *argv[]) return EXIT_FAILURE; } -static void -checkabsolutes(void) -{ - if (absolute_max_time < absolute_min_time) { - (void) fprintf(stderr, -_("%s: use of -v on system with floating time_t other than float or double\n"), - progname); - exit(EXIT_FAILURE); - } -} - static time_t yeartot(const intmax_t y) { @@ -666,11 +638,6 @@ abbr(struct tm *tmp) static const char * tformat(void) { - if (0.5 == (time_t) 0.5) { /* floating */ - if (sizeof (time_t) > sizeof (double)) - return "%Lg"; - return "%g"; - } if (0 > (time_t) -1) { /* signed */ if (sizeof (time_t) == sizeof (intmax_t)) return "%"PRIdMAX; -- 1.8.1.2

1 0

[PATCH] Use symbolic links to deduplicate installed files.
by Paul Eggert Aug. 11, 2013

Aug. 11, 2013

* Makefile (TZDIR_BASENAME): New macro. (TZDIR): Use it. (other_two): Remove. (right_posix, posix_right): Use a symbolic link if supported. This saves about 2 megabytes' worth of installed files. --- Makefile | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-) diff --git a/Makefile b/Makefile index 3659378..8b033a6 100644 --- a/Makefile +++ b/Makefile @@ -51,7 +51,8 @@ TOPDIR= /usr/local # (and subdirectories). # Use an absolute path name for TZDIR unless you're just testing the software. -TZDIR= $(TOPDIR)/etc/zoneinfo +TZDIR_BASENAME= zoneinfo +TZDIR= $(TOPDIR)/etc/$(TZDIR_BASENAME) # Types to try, as an alternative to time_t. int64_t should be first. TIME_T_ALTERNATIVES= int64_t int32_t uint32_t uint64_t @@ -390,15 +391,21 @@ right_only: zic leapseconds $(TDATA) # Therefore, the other two directories are now siblings of $(TZDIR). # You must replace all of $(TZDIR) to switch from not using leap seconds # to using them, or vice versa. -other_two: zic leapseconds $(TDATA) +right_posix: right_only + rm -fr $(TZDIR)-leaps + ln -s $(TZDIR_BASENAME) $(TZDIR)-leaps || \ + $(ZIC) -y $(YEARISTYPE) \ + -d $(TZDIR)-leaps -L leapseconds $(TDATA) $(ZIC) -y $(YEARISTYPE) -d $(TZDIR)-posix -L /dev/null $(TDATA) + +posix_right: posix_only + rm -fr $(TZDIR)-posix + ln -s $(TZDIR_BASENAME) $(TZDIR)-posix || \ + $(ZIC) -y $(YEARISTYPE) \ + -d $(TZDIR)-posix -L /dev/null $(TDATA) $(ZIC) -y $(YEARISTYPE) \ -d $(TZDIR)-leaps -L leapseconds $(TDATA) -posix_right: posix_only other_two - -right_posix: right_only other_two - zones: $(REDO) $(TZLIB): $(LIBOBJS) -- 1.8.1.2

1 0

[PATCH] Move McMurdo and South Pole to 'backward'.
by Paul Eggert Aug. 11, 2013

Aug. 11, 2013

This continues in the series of moving entries to 'backward' if they exist only because of obsolete tz rules about country codes. This change does not affect any time stamps after 1970. Unlike the previous change in this series, this one does affect time stamps before 1970, but that's OK as pre-1970 time stamps are out of scope for the tz database. * antarctica (Antarctica/McMurdo, Antarctica/South_Pole): Move to 'backward' and link to Pacific/Auckland. * backward: Move links here from 'antarctica'. * zone.tab: Coalesce McMurdo and South Pole, and add Scott Base to the description. --- antarctica | 18 ++++++------------ backward | 2 ++ zone.tab | 3 +-- 3 files changed, 9 insertions(+), 14 deletions(-) diff --git a/antarctica b/antarctica index 9bf2494..4cb7476 100644 --- a/antarctica +++ b/antarctica @@ -228,7 +228,8 @@ Zone Antarctica/Syowa 0 - zzz 1957 Jan 29 # Scott Island (never inhabited) # # year-round base -# Scott, Ross Island, since 1957-01, is like Antarctica/McMurdo. +# Scott Base, Ross Island, since 1957-01. +# See Pacific/Auckland. # # These rules for New Zealand are stolen from the `australasia' file. # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S @@ -337,16 +338,11 @@ Zone Antarctica/Palmer 0 - zzz 1965 -4:00 ChileAQ CL%sT # # -# McMurdo, Ross Island, since 1955-12 -# Zone NAME GMTOFF RULES FORMAT [UNTIL] -Zone Antarctica/McMurdo 0 - zzz 1956 - 12:00 NZAQ NZ%sT -# -# Amundsen-Scott, South Pole, continuously occupied since 1956-11-20 +# McMurdo Station, Ross Island, since 1955-12 +# See Pacific/Auckland. # -# From Paul Eggert (1996-09-03): -# Normally it wouldn't have a separate entry, since it's like the -# larger Antarctica/McMurdo since 1970, but it's too famous to omit. +# Amundsen-Scott South Pole Station, continuously occupied since 1956-11-20 +# See Pacific/Auckland. # # From Chris Carrier (1996-06-27): # Siple, the first commander of the South Pole station, @@ -367,5 +363,3 @@ Zone Antarctica/McMurdo 0 - zzz 1956 # makes all of the clocks run fast. So every couple of days, # we have to go around and set them back 5 minutes or so. # Maybe if we let them run fast all of the time, we'd get to leave here sooner!! -# -Link Antarctica/McMurdo Antarctica/South_Pole diff --git a/backward b/backward index 791db0c..c8c184e 100644 --- a/backward +++ b/backward @@ -27,6 +27,8 @@ Link America/Rio_Branco America/Porto_Acre Link America/Argentina/Cordoba America/Rosario Link America/Guadeloupe America/St_Barthelemy Link America/St_Thomas America/Virgin +Link Pacific/Auckland Antarctica/McMurdo +Link Pacific/Auckland Antarctica/South_Pole Link Europe/Oslo Arctic/Longyearbyen Link Asia/Ashgabat Asia/Ashkhabad Link Asia/Kolkata Asia/Calcutta diff --git a/zone.tab b/zone.tab index a6146f7..d9f9e4b 100644 --- a/zone.tab +++ b/zone.tab @@ -45,8 +45,7 @@ AI +1812-06304 America/Anguilla AL +4120+01950 Europe/Tirane AM +4011+04430 Asia/Yerevan AO -0848+01314 Africa/Luanda -AQ -7750+16636 Antarctica/McMurdo McMurdo Station, Ross Island -AQ -9000+00000 Antarctica/South_Pole Amundsen-Scott Station, South Pole +AQ -7750+16636 Pacific/Auckland McMurdo, South Pole, Scott (New Zealand time) AQ -6734-06808 Antarctica/Rothera Rothera Station, Adelaide Island AQ -6448-06406 Antarctica/Palmer Palmer Station, Anvers Island AQ -6736+06253 Antarctica/Mawson Mawson Station, Holme Bay -- 1.8.1.2

1 0

[PATCH] Change Indonesian time zone names to reflect common practice.
by Paul Eggert Aug. 11, 2013

Aug. 11, 2013

Catching up on some old business, I've pushed this proposed patch to the experimental repository. Comments welcome. ----- * asia (Asia/Dili, Asia/Jakarta, Asia/Pontianak, Asia/Makassar) (Asia/Jayapura): Use WIB/WITA/WIT rather than WIT/CIT/EIT, since it's typical to use Indonesian-language abbreviations even when writing in English. I surveyed the Internet and Google Books and found several independent English-language sources using WIB/WITA/WIT, whereas it seemed only tz-inspired sources used WIT/CIT/EIT. Problem reported several times, by George Ziegler, Priyadi Iman Nurcahyo, Zakaria, Jason Grimes, Martin Pitt, and Benny Lin; see Lin's summary of the reports in <http://mm.icann.org/pipermail/tz/2013-February/018609.html>. This change does not affect time zone offsets, just alphabetic abbreviations, such as tm_zone in the BSD-style struct tm. (Asia/Jakarta): Use BMT, not JMT, for mean time from 1923 to 1932, as Jakarta was called Batavia back then. --- asia | 59 ++++++++++++++++++++++++++++++++++++++--------------------- 1 file changed, 38 insertions(+), 21 deletions(-) diff --git a/asia b/asia index 79cfc48..5a824f8 100644 --- a/asia +++ b/asia @@ -6,7 +6,7 @@ # go ahead and edit the file (and please send any changes to # tz(a)iana.org for general use in the future). -# From Paul Eggert (2013-02-21): +# From Paul Eggert (2013-08-11): # # A good source for time zone historical data outside the U.S. is # Thomas G. Shanks and Rique Pottenger, The International Atlas (6th edition), @@ -44,11 +44,11 @@ # 4:00 GST Gulf* # 5:30 IST India # 7:00 ICT Indochina* -# 7:00 WIT west Indonesia -# 8:00 CIT central Indonesia +# 7:00 WIB west Indonesia (Waktu Indonesia Barat) +# 8:00 WITA central Indonesia (Waktu Indonesia Tengah) # 8:00 CST China # 9:00 CJT Central Japanese Time (1896/1937)* -# 9:00 EIT east Indonesia +# 9:00 WIT east Indonesia (Waktu Indonesia Timur) # 9:00 JST JDT Japan # 9:00 KST KDT Korea # 9:30 CST (Australian) Central Standard Time @@ -756,7 +756,7 @@ Zone Asia/Dili 8:22:20 - LMT 1912 8:00 - TLT 1942 Feb 21 23:00 # E Timor Time 9:00 - JST 1945 Sep 23 9:00 - TLT 1976 May 3 - 8:00 - CIT 2000 Sep 17 00:00 + 8:00 - WITA 2000 Sep 17 00:00 9:00 - TLT # India @@ -793,36 +793,53 @@ Zone Asia/Kolkata 5:53:28 - LMT 1880 # Kolkata # (Hollandia). For now, assume all Indonesian locations other than Jayapura # switched on 1945-09-23. # +# From Paul Eggert (2013-08-11): +# Normally the tz database uses English-language abbreviations, but in +# Indonesia it's typical to use Indonesian-language abbreviations even +# when writing in English. For example, see the English-language +# summary published by the Time and Frequency Laboratory of the +# Research Center for Calibration, Instrumentation and Metrology, +# Indonesia, <http://time.kim.lipi.go.id/time-eng.php> (2006-09-29). +# The abbreviations are: +# +# WIB - UTC+7 - Waktu Indonesia Barat (Indonesia western time) +# WITA - UTC+8 - Waktu Indonesia Tengah (Indonesia central time) +# WIT - UTC+9 - Waktu Indonesia Timur (Indonesia eastern time) +# # Zone NAME GMTOFF RULES FORMAT [UNTIL] +# Java, Sumatra Zone Asia/Jakarta 7:07:12 - LMT 1867 Aug 10 # Shanks & Pottenger say the next transition was at 1924 Jan 1 0:13, # but this must be a typo. - 7:07:12 - JMT 1923 Dec 31 23:47:12 # Jakarta + 7:07:12 - BMT 1923 Dec 31 23:47:12 # Batavia 7:20 - JAVT 1932 Nov # Java Time - 7:30 - WIT 1942 Mar 23 + 7:30 - WIB 1942 Mar 23 9:00 - JST 1945 Sep 23 - 7:30 - WIT 1948 May - 8:00 - WIT 1950 May - 7:30 - WIT 1964 - 7:00 - WIT + 7:30 - WIB 1948 May + 8:00 - WIB 1950 May + 7:30 - WIB 1964 + 7:00 - WIB +# west and central Borneo Zone Asia/Pontianak 7:17:20 - LMT 1908 May 7:17:20 - PMT 1932 Nov # Pontianak MT - 7:30 - WIT 1942 Jan 29 + 7:30 - WIB 1942 Jan 29 9:00 - JST 1945 Sep 23 - 7:30 - WIT 1948 May - 8:00 - WIT 1950 May - 7:30 - WIT 1964 - 8:00 - CIT 1988 Jan 1 - 7:00 - WIT + 7:30 - WIB 1948 May + 8:00 - WIB 1950 May + 7:30 - WIB 1964 + 8:00 - WITA 1988 Jan 1 + 7:00 - WIB +# Sulawesi, Lesser Sundas, east and south Borneo Zone Asia/Makassar 7:57:36 - LMT 1920 7:57:36 - MMT 1932 Nov # Macassar MT - 8:00 - CIT 1942 Feb 9 + 8:00 - WITA 1942 Feb 9 9:00 - JST 1945 Sep 23 - 8:00 - CIT + 8:00 - WITA +# Maluku Islands, West Papua, Papua Zone Asia/Jayapura 9:22:48 - LMT 1932 Nov - 9:00 - EIT 1944 Sep 1 + 9:00 - WIT 1944 Sep 1 9:30 - CST 1964 - 9:00 - EIT + 9:00 - WIT # Iran -- 1.8.1.2

1 0

can struct definitions from localtime.c be moved to private.h ?
by Alois Treindl Aug. 8, 2013

Aug. 8, 2013

The source file localtime.c includes the definitions for structures used in the binary (compiled) zone files. I am writing code which accesses these compiled zone files. It would be most convenient to have the struct definitions moved from localtime.c to a header file, e.g. private.h which I can include in other code. struct ttinfo struct lsinfo struct state struct rule

2 2

source code question regarding localtime.c PS
by Alois Treindl Aug. 8, 2013

Aug. 8, 2013

In localtime.c, function localsub() are these three lines of code: 1295 icycles = tcycles; 1296 if (tcycles - icycles >= 1 || icycles - tcycles >= 1) 1297 return NULL; I do not understand the reason why lines 1296 and 1297 exist. icycles and tcycles are equal. Their difference is always zero. Why test for it being not zero? PS: the reason why I am asking: I try to understand the source code of zdump.c It calls localtime() frequently, and has some cryptic code which depends on whether localtime() returned NULL. Therefore, I try to understand the conditions under which localtime() returns NULL. If that would be documented somewhee (I may have overlooked it), it would be great, as it is rather hard to understand it out of the terse code.

6 10

source code question regarding localtime.c
by Alois Treindl Aug. 7, 2013

Aug. 7, 2013

In localtime.c, function localsub() are these three lines of code: 1295 icycles = tcycles; 1296 if (tcycles - icycles >= 1 || icycles - tcycles >= 1) 1297 return NULL; I do not understand the reason why lines 1296 and 1297 exist. icycles and tcycles are equal. Their difference is always zero. Why test for it being not zero?

1 0