- tz - lists.iana.org

Time Conversoin Question [forwarded with permission]
by ado March 21, 1994

March 21, 1994

> From aaron(a)lehman.com Thu Mar 17 16:49:11 1994 > Return-Path: <aaron(a)lehman.com> > Received: from lehman.com by elsie.nci.nih.gov (4.1/SMI-4.1) > id AA28619; Thu, 17 Mar 94 16:49:08 EST > Received: from relay.lehman.com by lehman.com (8.6.4/LB 0.1) > id QAA19119; Thu, 17 Mar 1994 16:48:58 -0500 > Received: from killer.lehman.com by relay.lehman.com (4.1/LB-0.6) > id AA04769; Thu, 17 Mar 94 16:48:51 EST > Received: from yen.lehman.com by killer.lehman.com (5.0/SMI-SVR4) > id AA29096; Thu, 17 Mar 1994 16:48:48 +0500 > Date: Thu, 17 Mar 1994 16:48:48 +0500 > From: aaron(a)lehman.com (Aaron Akman) > Message-Id: <9403172148.AA29096(a)killer.lehman.com> > Received: by yen.lehman.com (4.1/SMI-4.1) > id AA03187; Thu, 17 Mar 94 16:48:45 EST > To: ado(a)elsie.nci.nih.gov > Subject: Time Conversion Question > Content-Length: 1037 > Status: RO > > Arthur, > > I've downloaded your timezone stuff (got pointers from Arnold Robbins > and Don Libes), and have a question: > > I'm looking to convert from GMT to one of a few timezones, or from one > timezone to another. I'm concerned about setting TZ and calling > tzset() because I think it changes some global state associated with > the process. If I were interrupted before setting TZ back and > re-calling tzset(), I could have an interrupt function that doesn't > have the right local TZ setting. I.e. > > get_other_local_time(char* tzsetting) > { > oldsetting = temporarily_set_TZ(tzsetting); > tzset(); > > do_time_stuff_with_alternate_TZ(); > > /* i could get interrupted here by a signal handler > that needs the real local time!! */ > > set_TZ_back(oldsetting); > tzset(); > } > > Is there a better way? Is it true the effect of tzset() global? I > haven't gone through the .c files in depth yet. > > It seems like this should be a common problem for a globally > distributed system. > > Thanks in advance for any advice, > Aaron Akman > aaron(a)lehman.com > 212 464 3978

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%V [forwarded]
by ado Feb. 28, 1994

Feb. 28, 1994

> From arnold(a)skeeve.atl.ga.us Sat Feb 26 21:12:21 1994 > Received: from emory.mathcs.emory.edu by elsie.nci.nih.gov (4.1/SMI-4.1) > id AA18459; Sat, 26 Feb 94 21:12:18 EST > Received: from skeeve.UUCP by > emory.mathcs.emory.edu (5.65/Emory_mathcs.3.4.19) via UUCP > id AA09626 ; Sat, 26 Feb 94 21:12:14 -0500 > Return-Path: arnold(a)skeeve.atl.ga.us > Received: by skeeve.atl.ga.us (/\==/\ Smail3.1.22.1 #22.1) > id <m0paal5-00013rC(a)skeeve.atl.ga.us>; Sat, 26 Feb 94 20:57 EST > Message-Id: <m0paal5-00013rC(a)skeeve.atl.ga.us> > From: arnold(a)skeeve.atl.ga.us > Date: Sat, 26 Feb 1994 20:57:26 -0500 > X-Ultrix: Just Say NO! > X-Important-Saying: Premature Optimization Is The Root Of All Evil. > X-Mailer: Mail User's Shell (7.2.5 10/14/92) > To: ado(a)elsie.nci.nih.gov > Subject: any comment on this? > Status: RO > > --- Forwarded mail from Tor Lillqvist <emory!tik.vtt.fi!tml> > > >From emory!tik.vtt.fi!tml Wed Feb 23 08:12:20 1994 > Return-Path: <emory!tik.vtt.fi!tml> > Received: by skeeve.atl.ga.us (/\==/\ Smail3.1.22.1 #22.1) > id <m0pZJNz-00013zC(a)skeeve.atl.ga.us>; Wed, 23 Feb 94 08:12 EST > Received: from tiuhti.tik.vtt.fi by > emory.mathcs.emory.edu (5.65/Emory_mathcs.3.4.19) via SMTP > id AA26972 ; Wed, 23 Feb 94 08:07:40 -0500 > Received: from localhost (tml@localhost) by tiuhti.tik.vtt.fi (8.6.5/8.6.5) id PAA28498; Wed, 23 Feb 1994 15:07:33 +0200 > Date: Wed, 23 Feb 1994 15:07:33 +0200 > From: Tor Lillqvist <emory!tik.vtt.fi!tml> > Message-Id: <199402231307.PAA28498(a)tiuhti.tik.vtt.fi> > To: arnold(a)skeeve.atl.ga.us (Arnold Robbins) > In-Reply-To: arnold(a)skeeve.atl.ga.us's message of 22 Feb 1994 17:21:29 -0800 > Subject: v27i207: strftime-6.0 - yet another strftime(3) and date(1), Part01/01 > Mime-Version: 1.0 > Content-Type: text/plain; charset=us-ascii > Content-Transfer-Encoding: 7bit > > >>>>> On 22 Feb 1994 17:21:29 -0800, arnold(a)skeeve.atl.ga.us (Arnold Robbins) said: > > (to wit: if the week containing January 1 has four or more > > days in the new year, then it is week 1, otherwise it is > > week 53 of the previous year and the next week is week 1). > > Nope, it can also be week 52 of the previous year. For instance this > year's (1994) January 1st an 2nd were in week 52 of 1993. "The highest > numbered week of the previous year (52 or 53)" would be more correct. > > I guess you really need a format character for "what year does the > week number output by %V refer to", also. Otherwise it's hard to find > any good use for the %V format in a program or script. If, for > instance, you use `date +%V` to form the name of a weekly log file > accumulated daily, then the logging from January 1 and 2 in 1994 > should go to the log file for week 52 of 1993, not to the log file for > week 52 of 1994... > > > --- End of forwarded message from Tor Lillqvist <emory!tik.vtt.fi!tml>

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tzcode94d.tar.gz and tzdata94d.tar.gz
by ado Feb. 24, 1994

Feb. 24, 1994

The files tzcode94d.tar.gz and tzdata94d.tar.gz are now available for anonymous ftp from the ~ftp/pub directory on elsie.nci.nih.gov (128.231.16.1). These files incorporate the changes to avoid clashes with POSIX semantics for zones such as GMT+4; some other very minor housekeeping is also present. --ado

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v27i207: strftime-6.0 - yet another strftime(3) and date(1), Part01/01
by Monty Solomon Feb. 23, 1994

Feb. 23, 1994

Begin forwarded message: Path: decwrl!vixie!vixie!not-for-mail From: arnold(a)skeeve.atl.ga.us (Arnold Robbins) Newsgroups: comp.sources.unix Subject: v27i207: strftime-6.0 - yet another strftime(3) and date(1), Part01/01 Date: 22 Feb 1994 17:21:29 -0800 Organization: Vixie Enterprises Lines: 1245 Sender: vixie(a)vix.com Approved: vixie(a)gw.home.vix.com Nntp-Posting-Host: gw.home.vix.com To: unix-sources(a)pa.dec.com Submitted-By: arnold(a)skeeve.atl.ga.us (Arnold Robbins) Posting-Number: Volume 27, Issue 207 Archive-Name: strftime-6.0/part01 [ this recurring package is the cleanest, nicest date(1) and strftime(3) i have ever seen, including all free or vendor systems. --vix ] It seems to be an annual event, something in the circling of the stars overhead, that requires me to post this, at least once a year. (:-) This version fixes bugs in the calculations for %U, %W, and %V and output formats of several of the others (they now have leading zeros if necessary). It also fixes a small bug in date.c. Although this is only the fourth version posted c.s.u, it is the sixth one to go to the net, the first two were in comp.sources.misc. So I don't know if this is strftime 4.0 or 6.0, you can decide. I sincerely hope this will be it (at least 'til next year! :-) Arnold Robbins -- The Basement Computer | Laundry increases Internet: arnold(a)skeeve.ATL.GA.US | exponentially in the UUCP: emory!skeeve!arnold | number of children. Bitnet: Forget it. Get on a real network. | -- Miriam Robbins #! /bin/sh echo - 'README' cat << 'EOF' > 'README' Tue Feb 15 08:26:04 EST 1994 This package implements the Posix 1003.2 date command, as a wrapper around an extended version of the ANSI strftime(3) library routine. Everything in it is public domain. Arnold Robbins -- The Basement Computer | Laundry increases Internet: arnold(a)skeeve.ATL.GA.US | exponentially in the UUCP: { gatech, emory }!skeeve!arnold | number of children. Bitnet: Forget it. Get on a real network. | -- Miriam Robbins EOF echo - 'Makefile' cat << 'EOF' > 'Makefile' # Makefile for PD date and strftime SRCS= date.c strftime.c OBJS= date.o strftime.o DOCS= date.1 strftime.3 # Uncomment the define of HAVE_TZNAME if your system has the tzname[] array. # Uncomment the define of TM_IN_SYS_TIME if struct tm is in <sys/time.h> CFLAGS= -O #-DHAVE_TZNAME #-DTM_IN_SYS_TIME date: $(OBJS) $(CC) $(CFLAGS) $(OBJS) -o $@ date.o: date.c strftime.o: strftime.c EOF echo - 'date.1' cat << 'EOF' > 'date.1' .TH DATE 1 .SH NAME date \- write the date and time .SH SYNOPSIS .B date [ .B \-u ] [ .RI + format ] .SH DESCRIPTION .I Date writes the current date and time to the standard output. It is intended to be compliant with draft 11 of the Posix 1003.2 Command Language and Utilities standard. Therefore, it is purposely .I not usable by the super-user for setting the system time. .LP .I Date accepts one option: .TP .B \-u Perform operations as if the .B TZ environment variable was set to .BR GMT0 . .LP If an argument to .I date is given that begins with a ``+'', then the output is controlled by the contents of the rest of the string. Normal text is output unmodified, while field descriptors in the format string are substituted for. .LP The .I date program is essentially a wrapper around .IR strftime (3); see there for a description of the available formatting options. .LP If no format string is given, or if it does not begin with a ``+'', then the default format of \fB"%a %b %e %H:%M:%S %Z %Y"\fR will be used. This produces the traditional style of output, such as ``Sun Mar 17 10:32:47 EST 1991''. .SH SEE ALSO time(2), strftime(3), localtime(3) .SH BUGS This version only works for the POSIX locale. .SH AUTHOR .nf Arnold Robbins .sp INTERNET: arnold(a)skeeve.atl.ga.us UUCP: emory!skeeve!arnold Phone: +1 404 248 9324 .fi EOF echo - 'date.c' cat << 'EOF' > 'date.c' /* * date.c * * Public domain implementation of Posix 1003.2 * date command. Lets strftime() do the dirty work. * * Arnold Robbins * arnold(a)skeeve.atl.ga.us * April, 1991 * * Bug fix courtesy of Chris Ritson (C.R.Ritson(a)newcastle.ac.uk) * February, 1994. */ #include <stdio.h> #include <sys/types.h> #include <time.h> extern char *malloc(); extern size_t strftime(); extern int getopt(); extern int optind; int main(argc, argv) int argc; char **argv; { time_t clock; struct tm *now; int c, size, ret; char *defhow = "%a %b %e %H:%M:%S %Z %Y"; char *howto = defhow; char *buf; while ((c = getopt(argc, argv, "u")) != -1) switch (c) { case 'u': putenv("TZ=GMT0"); break; default: fprintf(stderr, "usage: %s [-u] [+format_str]\n", argv[0]); exit(1); } time(& clock); now = localtime(& clock); if (optind < argc && argv[optind][0] == '+') howto = & argv[optind][1]; size = strlen(howto) * 10; if (size < 26) size = 26; if ((buf = malloc(size)) == NULL) { perror("not enough memory"); exit(1); } ret = strftime(buf, size, howto, now); if (ret != 0) printf("%s\n", buf); else { fprintf(stderr, "conversion failed\n"); exit(1); } exit(0); } EOF echo - 'strftime.3' cat << 'EOF' > 'strftime.3' .TH STRFTIME 3 .SH NAME strftime \- generate formatted time information .SH SYNOPSIS .ft B .nf #include <sys/types.h> #include <time.h> .sp size_t strftime(char *s, size_t maxsize, const char *format, const struct tm *timeptr); .SH DESCRIPTION The following description is transcribed verbatim from the December 7, 1988 draft standard for ANSI C. This draft is essentially identical in technical content to the final version of the standard. .LP The .B strftime function places characters into the array pointed to by .B s as controlled by the string pointed to by .BR format . The format shall be a multibyte character sequence, beginning and ending in its initial shift state. The .B format string consists of zero or more conversion specifiers and ordinary multibyte characters. A conversion specifier consists of a .B % character followed by a character that determines the behavior of the conversion specifier. All ordinary multibyte characters (including the terminating null character) are copied unchanged into the array. If copying takes place between objects that overlap the behavior is undefined. No more than .B maxsize characters are placed into the array. Each conversion specifier is replaced by appropriate characters as described in the following list. The appropriate characters are determined by the .B LC_TIME category of the current locale and by the values contained in the structure pointed to by .BR timeptr . .TP .B %a is replaced by the locale's abbreviated weekday name. .TP .B %A is replaced by the locale's full weekday name. .TP .B %b is replaced by the locale's abbreviated month name. .TP .B %B is replaced by the locale's full month name. .TP .B %c is replaced by the locale's appropriate date and time representation. .TP .B %d is replaced by the day of the month as a decimal number .RB ( 01 - 31 ). .TP .B %H is replaced by the hour (24-hour clock) as a decimal number .RB ( 00 - 23 ). .TP .B %I is replaced by the hour (12-hour clock) as a decimal number .RB ( 01 - 12 ). .TP .B %j is replaced by the day of the year as a decimal number .RB ( 001 - 366 ). .TP .B %m is replaced by the month as a decimal number .RB ( 01 - 12 ). .TP .B %M is replaced by the minute as a decimal number .RB ( 00 - 59 ). .TP .B %p is replaced by the locale's equivalent of the AM/PM designations associated with a 12-hour clock. .TP .B %S is replaced by the second as a decimal number .RB ( 00 - 61 ). .TP .B %U is replaced by the week number of the year (the first Sunday as the first day of week 1) as a decimal number .RB ( 00 - 53 ). .TP .B %w is replaced by the weekday as a decimal number .RB [ "0 " (Sunday)- 6 ]. .TP .B %W is replaced by the week number of the year (the first Monday as the first day of week 1) as a decimal number .RB ( 00 - 53 ). .TP .B %x is replaced by the locale's appropriate date representation. .TP .B %X is replaced by the locale's appropriate time representation. .TP .B %y is replaced by the year without century as a decimal number .RB ( 00 - 99 ). .TP .B %Y is replaced by the year with century as a decimal number. .TP .B %Z is replaced by the time zone name or abbreviation, or by no characters if no time zone is determinable. .TP .B %% is replaced by .BR % . .LP If a conversion specifier is not one of the above, the behavior is undefined. .SH RETURNS If the total number of resulting characters including the terminating null character is not more than .BR maxsize , the .B strftime function returns the number of characters placed into the array pointed to by .B s not including the terminating null character. Otherwise, zero is returned and the contents of the array are indeterminate. .SH NON-ANSI EXTENSIONS If .B SYSV_EXT is defined when the routine is compiled, then the following additional conversions will be available. These are borrowed from the System V .IR cftime (3) and .IR ascftime (3) routines. .TP .B %D is equivalent to specifying .BR %m/%d/%y . .TP .B %e is replaced by the day of the month, padded with a blank if it is only one digit. .TP .B %h is equivalent to .BR %b , above. .TP .B %n is replaced with a newline character (\s-1ASCII LF\s+1). .TP .B %r is equivalent to specifying .BR "%I:%M:%S %p" . .TP .B %R is equivalent to specifying .BR %H:%M . .TP .B %T is equivalent to specifying .BR %H:%M:%S . .TP .B %t is replaced with a \s-1TAB\s+1 character. .PP If .B SUNOS_EXT is defined when the routine is compiled, then the following additional conversions will be available. These are borrowed from the SunOS version of .IR strftime . .TP .B %k is replaced by the hour (24-hour clock) as a decimal number .RB ( 0 - 23 ). Single digit numbers are padded with a blank. .TP .B %l is replaced by the hour (12-hour clock) as a decimal number .RB ( 1 - 12 ). Single digit numbers are padded with a blank. .SH POSIX 1003.2 EXTENSIONS If .B POSIX2_DATE is defined, then all of the conversions available with .B SYSV_EXT and .B SUNOS_EXT are available, as well as the following additional conversions: .TP .B %C The century, as a number between 00 and 99. .TP .B %u is replaced by the weekday as a decimal number .RB [ "1 " (Monday)- 7 ]. .TP .B %V is replaced by the week number of the year (the first Monday as the first day of week 1) as a decimal number .RB ( 01 - 53 ). The method for determining the week number is as specified by ISO 8601 (to wit: if the week containing January 1 has four or more days in the new year, then it is week 1, otherwise it is week 53 of the previous year and the next week is week 1). .LP The text of the POSIX standard for the .I date utility describes .B %U and .B %W this way: .TP .B %U is replaced by the week number of the year (the first Sunday as the first day of week 1) as a decimal number .RB ( 00 - 53 ). All days in a new year preceding the first Sunday are considered to be in week 0. .TP .B %W is replaced by the week number of the year (the first Monday as the first day of week 1) as a decimal number .RB ( 00 - 53 ). All days in a new year preceding the first Monday are considered to be in week 0. .LP In addition, the alternate representations .BR %Ec , .BR %EC , .BR %Ex , .BR %Ey , .BR %EY , .BR %Od , .BR %Oe , .BR %OH , .BR %OI , .BR %Om , .BR %OM , .BR %OS , .BR %Ou , .BR %OU , .BR %OV , .BR %Ow , .BR %OW , and .B %Oy are recognized, but their normal representations are used. .SH VMS EXTENSIONS If .B VMS_EXT is defined, then the following additional conversion is available: .TP .B %v The date in VMS format (e.g. 20-JUN-1991). .SH SEE ALSO .IR time (2), .IR ctime (3), .IR localtime (3), .IR tzset (3) .SH BUGS This version does not handle multibyte characters or pay attention to the setting of the .B LC_TIME environment variable. .LP It is not clear what is ``appropriate'' for the C locale; the values returned are a best guess on the author's part. .SH CAVEATS The pre-processor symbol .B POSIX_SEMANTICS is automatically defined, which forces the code to call .IR tzset (3) whenever the .B TZ environment variable has changed. If this routine will be used in an application that will not be changing .BR TZ , then there may be some performance improvements by not defining .BR POSIX_SEMANTICS . .SH AUTHOR .nf Arnold Robbins .sp INTERNET: arnold(a)skeeve.atl.ga.us UUCP: emory!skeeve!arnold Phone: +1 404 248 9324 .fi .SH ACKNOWLEDGEMENTS Thanks to Geoff Clare <gwc(a)root.co.uk> for helping debug earlier versions of this routine, and for advice about POSIX semantics. Additional thanks to Arthur David Olsen <ado(a)elsie.nci.nih.gov> for some code improvements. Thanks also to Tor Lillqvist <tml(a)tik.vtt.fi> for code fixes to the ISO 8601 code. EOF echo - 'strftime.c' cat << 'EOF' > 'strftime.c' /* * strftime.c * * Public-domain implementation of ANSI C library routine. * * It's written in old-style C for maximal portability. * However, since I'm used to prototypes, I've included them too. * * If you want stuff in the System V ascftime routine, add the SYSV_EXT define. * For extensions from SunOS, add SUNOS_EXT. * For stuff needed to implement the P1003.2 date command, add POSIX2_DATE. * For VMS dates, add VMS_EXT. * For complete POSIX semantics, add POSIX_SEMANTICS. * * The code for %c, %x, and %X is my best guess as to what's "appropriate". * This version ignores LOCALE information. * It also doesn't worry about multi-byte characters. * So there. * * This file is also shipped with GAWK (GNU Awk), gawk specific bits of * code are included if GAWK is defined. * * Arnold Robbins * January, February, March, 1991 * Updated March, April 1992 * Updated April, 1993 * Updated February, 1994 * * Fixes from ado(a)elsie.nci.nih.gov * February 1991, May 1992 * Fixes from Tor Lillqvist tml(a)tik.vtt.fi * May, 1993 * Further fixes from ado(a)elsie.nci.nih.gov * February 1994 */ #ifndef GAWK #include <stdio.h> #include <ctype.h> #include <string.h> #include <time.h> #endif #include <sys/types.h> #if defined(TM_IN_SYS_TIME) || ! defined(GAWK) #include <sys/time.h> #endif /* defaults: season to taste */ #define SYSV_EXT 1 /* stuff in System V ascftime routine */ #define SUNOS_EXT 1 /* stuff in SunOS strftime routine */ #define POSIX2_DATE 1 /* stuff in Posix 1003.2 date command */ #define VMS_EXT 1 /* include %v for VMS date format */ #ifndef GAWK #define POSIX_SEMANTICS 1 /* call tzset() if TZ changes */ #endif #if defined(POSIX2_DATE) #if ! defined(SYSV_EXT) #define SYSV_EXT 1 #endif #if ! defined(SUNOS_EXT) #define SUNOS_EXT 1 #endif #endif #if defined(POSIX2_DATE) #define adddecl(stuff) stuff #else #define adddecl(stuff) #endif #undef strchr /* avoid AIX weirdness */ #ifndef __STDC__ #define const /**/ extern void *malloc(); extern void *realloc(); extern void tzset(); extern char *strchr(); extern char *getenv(); static int weeknumber(); adddecl(static int iso8601wknum();) #else extern void *malloc(unsigned count); extern void *realloc(void *ptr, unsigned count); extern void tzset(void); extern char *strchr(const char *str, int ch); extern char *getenv(const char *v); static int weeknumber(const struct tm *timeptr, int firstweekday); adddecl(static int iso8601wknum(const struct tm *timeptr);) #endif #ifdef __GNUC__ #define inline __inline__ #else #define inline /**/ #endif #define range(low, item, hi) max(low, min(item, hi)) #if !defined(OS2) && !defined(MSDOS) && defined(HAVE_TZNAME) extern char *tzname[2]; extern int daylight; #endif /* min --- return minimum of two numbers */ #ifndef __STDC__ static inline int min(a, b) int a, b; #else static inline int min(int a, int b) #endif { return (a < b ? a : b); } /* max --- return maximum of two numbers */ #ifndef __STDC__ static inline int max(a, b) int a, b; #else static inline int max(int a, int b) #endif { return (a > b ? a : b); } /* strftime --- produce formatted time */ #ifndef __STDC__ size_t strftime(s, maxsize, format, timeptr) char *s; size_t maxsize; const char *format; const struct tm *timeptr; #else size_t strftime(char *s, size_t maxsize, const char *format, const struct tm *timeptr) #endif { char *endp = s + maxsize; char *start = s; auto char tbuf[100]; int i; static short first = 1; #ifdef POSIX_SEMANTICS static char *savetz = NULL; static int savetzlen = 0; char *tz; #endif /* POSIX_SEMANTICS */ /* various tables, useful in North America */ static const char *days_a[] = { "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", }; static const char *days_l[] = { "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday", }; static const char *months_a[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec", }; static const char *months_l[] = { "January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December", }; static const char *ampm[] = { "AM", "PM", }; if (s == NULL || format == NULL || timeptr == NULL || maxsize == 0) return 0; /* quick check if we even need to bother */ if (strchr(format, '%') == NULL && strlen(format) + 1 >= maxsize) return 0; #ifndef POSIX_SEMANTICS if (first) { tzset(); first = 0; } #else /* POSIX_SEMANTICS */ tz = getenv("TZ"); if (first) { if (tz != NULL) { int tzlen = strlen(tz); savetz = (char *) malloc(tzlen + 1); if (savetz != NULL) { savetzlen = tzlen + 1; strcpy(savetz, tz); } } tzset(); first = 0; } /* if we have a saved TZ, and it is different, recapture and reset */ if (tz && savetz && (tz[0] != savetz[0] || strcmp(tz, savetz) != 0)) { i = strlen(tz) + 1; if (i > savetzlen) { savetz = (char *) realloc(savetz, i); if (savetz) { savetzlen = i; strcpy(savetz, tz); } } else strcpy(savetz, tz); tzset(); } #endif /* POSIX_SEMANTICS */ for (; *format && s < endp - 1; format++) { tbuf[0] = '\0'; if (*format != '%') { *s++ = *format; continue; } again: switch (*++format) { case '\0': *s++ = '%'; goto out; case '%': *s++ = '%'; continue; case 'a': /* abbreviated weekday name */ if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6) strcpy(tbuf, "?"); else strcpy(tbuf, days_a[timeptr->tm_wday]); break; case 'A': /* full weekday name */ if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6) strcpy(tbuf, "?"); else strcpy(tbuf, days_l[timeptr->tm_wday]); break; #ifdef SYSV_EXT case 'h': /* abbreviated month name */ #endif case 'b': /* abbreviated month name */ if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11) strcpy(tbuf, "?"); else strcpy(tbuf, months_a[timeptr->tm_mon]); break; case 'B': /* full month name */ if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11) strcpy(tbuf, "?"); else strcpy(tbuf, months_l[timeptr->tm_mon]); break; case 'c': /* appropriate date and time representation */ sprintf(tbuf, "%s %s %2d %02d:%02d:%02d %d", days_a[range(0, timeptr->tm_wday, 6)], months_a[range(0, timeptr->tm_mon, 11)], range(1, timeptr->tm_mday, 31), range(0, timeptr->tm_hour, 23), range(0, timeptr->tm_min, 59), range(0, timeptr->tm_sec, 61), timeptr->tm_year + 1900); break; case 'd': /* day of the month, 01 - 31 */ i = range(1, timeptr->tm_mday, 31); sprintf(tbuf, "%02d", i); break; case 'H': /* hour, 24-hour clock, 00 - 23 */ i = range(0, timeptr->tm_hour, 23); sprintf(tbuf, "%02d", i); break; case 'I': /* hour, 12-hour clock, 01 - 12 */ i = range(0, timeptr->tm_hour, 23); if (i == 0) i = 12; else if (i > 12) i -= 12; sprintf(tbuf, "%02d", i); break; case 'j': /* day of the year, 001 - 366 */ sprintf(tbuf, "%03d", timeptr->tm_yday + 1); break; case 'm': /* month, 01 - 12 */ i = range(0, timeptr->tm_mon, 11); sprintf(tbuf, "%02d", i + 1); break; case 'M': /* minute, 00 - 59 */ i = range(0, timeptr->tm_min, 59); sprintf(tbuf, "%02d", i); break; case 'p': /* am or pm based on 12-hour clock */ i = range(0, timeptr->tm_hour, 23); if (i < 12) strcpy(tbuf, ampm[0]); else strcpy(tbuf, ampm[1]); break; case 'S': /* second, 00 - 61 */ i = range(0, timeptr->tm_sec, 61); sprintf(tbuf, "%02d", i); break; case 'U': /* week of year, Sunday is first day of week */ sprintf(tbuf, "%02d", weeknumber(timeptr, 0)); break; case 'w': /* weekday, Sunday == 0, 0 - 6 */ i = range(0, timeptr->tm_wday, 6); sprintf(tbuf, "%d", i); break; case 'W': /* week of year, Monday is first day of week */ sprintf(tbuf, "%02d", weeknumber(timeptr, 1)); break; case 'x': /* appropriate date representation */ sprintf(tbuf, "%s %s %2d %d", days_a[range(0, timeptr->tm_wday, 6)], months_a[range(0, timeptr->tm_mon, 11)], range(1, timeptr->tm_mday, 31), timeptr->tm_year + 1900); break; case 'X': /* appropriate time representation */ sprintf(tbuf, "%02d:%02d:%02d", range(0, timeptr->tm_hour, 23), range(0, timeptr->tm_min, 59), range(0, timeptr->tm_sec, 61)); break; case 'y': /* year without a century, 00 - 99 */ i = timeptr->tm_year % 100; sprintf(tbuf, "%02d", i); break; case 'Y': /* year with century */ sprintf(tbuf, "%d", 1900 + timeptr->tm_year); break; case 'Z': /* time zone name or abbrevation */ #ifdef HAVE_TZNAME i = (daylight && timeptr->tm_isdst); /* 0 or 1 */ strcpy(tbuf, tzname[i]); #else strcpy(tbuf, timeptr->tm_zone); #endif break; #ifdef SYSV_EXT case 'n': /* same as \n */ tbuf[0] = '\n'; tbuf[1] = '\0'; break; case 't': /* same as \t */ tbuf[0] = '\t'; tbuf[1] = '\0'; break; case 'D': /* date as %m/%d/%y */ strftime(tbuf, sizeof tbuf, "%m/%d/%y", timeptr); break; case 'e': /* day of month, blank padded */ sprintf(tbuf, "%2d", range(1, timeptr->tm_mday, 31)); break; case 'r': /* time as %I:%M:%S %p */ strftime(tbuf, sizeof tbuf, "%I:%M:%S %p", timeptr); break; case 'R': /* time as %H:%M */ strftime(tbuf, sizeof tbuf, "%H:%M", timeptr); break; case 'T': /* time as %H:%M:%S */ strftime(tbuf, sizeof tbuf, "%H:%M:%S", timeptr); break; #endif #ifdef SUNOS_EXT case 'k': /* hour, 24-hour clock, blank pad */ sprintf(tbuf, "%2d", range(0, timeptr->tm_hour, 23)); break; case 'l': /* hour, 12-hour clock, 1 - 12, blank pad */ i = range(0, timeptr->tm_hour, 23); if (i == 0) i = 12; else if (i > 12) i -= 12; sprintf(tbuf, "%2d", i); break; #endif #ifdef VMS_EXT case 'v': /* date as dd-bbb-YYYY */ sprintf(tbuf, "%02d-%3.3s-%4d", range(1, timeptr->tm_mday, 31), months_a[range(0, timeptr->tm_mon, 11)], timeptr->tm_year + 1900); for (i = 3; i < 6; i++) if (islower(tbuf[i])) tbuf[i] = toupper(tbuf[i]); break; #endif #ifdef POSIX2_DATE case 'C': sprintf(tbuf, "%02d", (timeptr->tm_year + 1900) / 100); break; case 'E': case 'O': /* POSIX locale extensions, ignored for now */ goto again; case 'V': /* week of year according ISO 8601 */ #if defined(GAWK) && defined(VMS_EXT) { extern int do_lint; extern void warning(); static int warned = 0; if (! warned && do_lint) { warned = 1; warning( "conversion %%V added in P1003.2; for VMS style date, use %%v"); } } #endif sprintf(tbuf, "%02d", iso8601wknum(timeptr)); break; case 'u': /* ISO 8601: Weekday as a decimal number [1 (Monday) - 7] */ sprintf(tbuf, "%d", timeptr->tm_wday == 0 ? 7 : timeptr->tm_wday); break; #endif /* POSIX2_DATE */ default: tbuf[0] = '%'; tbuf[1] = *format; tbuf[2] = '\0'; break; } i = strlen(tbuf); if (i) { if (s + i < endp - 1) { strcpy(s, tbuf); s += i; } else return 0; } } out: if (s < endp && *format == '\0') { *s = '\0'; return (s - start); } else return 0; } #ifdef POSIX2_DATE /* iso8601wknum --- compute week number according to ISO 8601 */ #ifndef __STDC__ static int iso8601wknum(timeptr) const struct tm *timeptr; #else static int iso8601wknum(const struct tm *timeptr) #endif { /* * From 1003.2: * If the week (Monday to Sunday) containing January 1 * has four or more days in the new year, then it is week 1; * otherwise it is week 53 of the previous year, and the * next week is week 1. * * ADR: This means if Jan 1 was Monday through Thursday, * it was week 1, otherwise week 53. */ int weeknum, jan1day, diff; /* get week number, Monday as first day of the week */ weeknum = weeknumber(timeptr, 1); /* * With thanks and tip of the hatlo to tml(a)tik.vtt.fi * * What day of the week does January 1 fall on? * We know that * (timeptr->tm_yday - jan1.tm_yday) MOD 7 == * (timeptr->tm_wday - jan1.tm_wday) MOD 7 * and that * jan1.tm_yday == 0 * and that * timeptr->tm_wday MOD 7 == timeptr->tm_wday * from which it follows that. . . */ jan1day = timeptr->tm_wday - (timeptr->tm_yday % 7); if (jan1day < 0) jan1day += 7; /* * If Jan 1 was a Monday through Thursday, it was in * week 1. Otherwise it was last year's week 53, which is * this year's week 0. * * What does that mean? * If Jan 1 was Monday, the week number is exactly right, it can * never be 0. * If it was Tuesday through Thursday, the weeknumber is one * less than it should be, so we add one. * Otherwise, Friday, Saturday or Sunday, the week number is * OK, but if it is 0, it needs to be 53. */ switch (jan1day) { case 1: /* Monday */ break; case 2: /* Tuesday */ case 3: /* Wednedsday */ case 4: /* Thursday */ weeknum++; break; case 5: /* Friday */ case 6: /* Saturday */ case 0: /* Sunday */ if (weeknum == 0) weeknum = 53; break; } return weeknum; } #endif /* weeknumber --- figure how many weeks into the year */ /* With thanks and tip of the hatlo to ado(a)elsie.nci.nih.gov */ #ifndef __STDC__ static int weeknumber(timeptr, firstweekday) const struct tm *timeptr; int firstweekday; #else static int weeknumber(const struct tm *timeptr, int firstweekday) #endif { int wday = timeptr->tm_wday; int ret; if (firstweekday == 1) { if (wday == 0) /* sunday */ wday = 6; else wday--; } ret = ((timeptr->tm_yday + 7 - wday) / 7); if (ret < 0) ret = 0; return ret; } #if 0 /* ADR --- I'm loathe to mess with ado's code ... */ Date: Wed, 24 Apr 91 20:54:08 MDT From: Michal Jaegermann <audfax!emory!vm.ucs.UAlberta.CA!NTOMCZAK> To: arnold(a)audiofax.com Hi Arnold, in a process of fixing of strftime() in libraries on Atari ST I grabbed some pieces of code from your own strftime. When doing that it came to mind that your weeknumber() function compiles a little bit nicer in the following form: /* * firstweekday is 0 if starting in Sunday, non-zero if in Monday */ { return (timeptr->tm_yday - timeptr->tm_wday + (firstweekday ? (timeptr->tm_wday ? 8 : 1) : 7)) / 7; } How nicer it depends on a compiler, of course, but always a tiny bit. Cheers, Michal ntomczak(a)vm.ucs.ualberta.ca #endif #ifdef TEST_STRFTIME /* * NAME: * tst * * SYNOPSIS: * tst * * DESCRIPTION: * "tst" is a test driver for the function "strftime". * * OPTIONS: * None. * * AUTHOR: * Karl Vogel * Control Data Systems, Inc. * vogelke(a)c-17igp.wpafb.af.mil * * BUGS: * None noticed yet. * * COMPILE: * cc -o tst -DTEST_STRFTIME strftime.c */ /* ADR: I reformatted this to my liking, and deleted some unneeded code. */ #ifndef NULL #include <stdio.h> #endif #include <sys/time.h> #include <string.h> #define MAXTIME 132 /* * Array of time formats. */ static char *array[] = { "(%%A) full weekday name, var length (Sunday..Saturday) %A", "(%%B) full month name, var length (January..December) %B", "(%%C) Century %C", "(%%D) date (%%m/%%d/%%y) %D", "(%%E) Locale extensions (ignored) %E", "(%%H) hour (24-hour clock, 00..23) %H", "(%%I) hour (12-hour clock, 01..12) %I", "(%%M) minute (00..59) %M", "(%%O) Locale extensions (ignored) %O", "(%%R) time, 24-hour (%%H:%%M) %R", "(%%S) second (00..61) %S", "(%%T) time, 24-hour (%%H:%%M:%%S) %T", "(%%U) week of year, Sunday as first day of week (00..53) %U", "(%%V) week of year according to ISO 8601 %V", "(%%W) week of year, Monday as first day of week (00..53) %W", "(%%X) appropriate locale time representation (%H:%M:%S) %X", "(%%Y) year with century (1970...) %Y", "(%%Z) timezone (EDT), or blank if timezone not determinable %Z", "(%%a) locale's abbreviated weekday name (Sun..Sat) %a", "(%%b) locale's abbreviated month name (Jan..Dec) %b", "(%%c) full date (Sat Nov 4 12:02:33 1989)%n%t%t%t %c", "(%%d) day of the month (01..31) %d", "(%%e) day of the month, blank-padded ( 1..31) %e", "(%%h) should be same as (%%b) %h", "(%%j) day of the year (001..366) %j", "(%%k) hour, 24-hour clock, blank pad ( 0..23) %k", "(%%l) hour, 12-hour clock, blank pad ( 0..12) %l", "(%%m) month (01..12) %m", "(%%p) locale's AM or PM based on 12-hour clock %p", "(%%r) time, 12-hour (same as %%I:%%M:%%S %%p) %r", "(%%u) ISO 8601: Weekday as decimal number [1 (Monday) - 7] %u", "(%%v) VAX date (dd-bbb-YYYY) %v", "(%%w) day of week (0..6, Sunday == 0) %w", "(%%x) appropriate locale date representation %x", "(%%y) last two digits of year (00..99) %y", (char *) NULL }; /* main routine. */ int main(argc, argv) int argc; char **argv; { long time(); char *next; char string[MAXTIME]; int k; int length; struct tm *tm; long clock; /* Call the function. */ clock = time((long *) 0); tm = localtime(&clock); for (k = 0; next = array[k]; k++) { length = strftime(string, MAXTIME, next, tm); printf("%s\n", string); } exit(0); } #endif /* TEST_STRFTIME */ EOF

1 0

Re: Standard for timezone handling with TZ
by ado Feb. 22, 1994

Feb. 22, 1994

Attached is my current best effort at dealing with "GMT" files in the time zone package. I'd very much welcome any feedback. --ado # @(#)etcetera 7.2 # All of these are set up just so people can "zic -l" to a timezone # that's right for their area, even if it doesn't have a name or DST rules # (half hour zones are too much to bother with -- when someone asks!) Zone GMT 0 - GMT Link GMT UTC Link GMT UCT Link GMT Universal Link GMT Greenwich Link GMT Zulu Link GMT GMT-0 Link GMT GMT+0 Link GMT GMT0 # We use POSIX-style signedness in the names and output, # internal-style signedness in the specifications. # These are shoved down into an "Etc" directory so we get a name change-- # in earlier incarnations, we had lines such as # Zone GMT-12 -12 - GMT-1200 # and do not want things to change quietly if someone accustomed to the old # way does a # zic -l GMT-12 Zone Etc/GMT-12 12 - GMT-12 Zone Etc/GMT-11 11 - GMT-11 Zone Etc/GMT-10 10 - GMT-10 Zone Etc/GMT-9 9 - GMT-9 Zone Etc/GMT-8 8 - GMT-8 Zone Etc/GMT-7 7 - GMT-7 Zone Etc/GMT-6 6 - GMT-6 Zone Etc/GMT-5 5 - GMT-5 Zone Etc/GMT-4 4 - GMT-4 Zone Etc/GMT-3 3 - GMT-3 Zone Etc/GMT-2 2 - GMT-2 Zone Etc/GMT-1 1 - GMT-1 Zone Etc/GMT+1 -1 - GMT+1 Zone Etc/GMT+2 -2 - GMT+2 Zone Etc/GMT+3 -3 - GMT+3 Zone Etc/GMT+4 -4 - GMT+4 Zone Etc/GMT+5 -5 - GMT+5 Zone Etc/GMT+6 -6 - GMT+6 Zone Etc/GMT+7 -7 - GMT+7 Zone Etc/GMT+8 -8 - GMT+8 Zone Etc/GMT+9 -9 - GMT+9 Zone Etc/GMT+10 -10 - GMT+10 Zone Etc/GMT+11 -11 - GMT+11 Zone Etc/GMT+12 -12 - GMT+12 Zone Etc/GMT+13 -13 - GMT+13 # GMT offset 12 hours with DST

2 1

Re: Standard for timezone handling with TZ
by ado Feb. 14, 1994

Feb. 14, 1994

> That's a bug in the Olson rules; they aren't compatible with Posix > 1003.1-1990. Thanks for pointing it out. Here's a conservative patch > to Olson's latest version which renames `GMT-4' to `GMT-0400' to avoid > the bug. > > Another possibility is simply to remove the GMT[-+]* rules, since their > sign is the opposite of the sign in the Posix TZ string, and this is confusing. My guess is it's best to keep some sort of GMT rules; as the etcetera file notes, # All of these are set up just so people can "zic -l" to a timezone # that's right for their area, even if it doesn't have a name or dst rules # (half hour zones are too much to bother with -- when someone asks!) and if you don't have the rules you can't do the "zic -l". (Whether there should be some mechanism to establish a rule-based rather than file-based time zone as local time is another question.) > *** etcetera 1992/04/23 17:34:35 7.1 > --- etcetera 1994/02/10 19:49:45 7.1.1.1 > *************** > *** 6,55 **** > > Zone GMT 0 - GMT > > ! Zone GMT-12 -12 - GMT-1200 > ! Zone GMT-11 -11 - GMT-1100 Is it better to render these as, for example, > Zone GMT 0 - GMT > > ! Zone GMT+1200 -12 - GMT+1200 > ! Zone GMT+1100 -11 - GMT+1100 Or, given Casper H. S. Dik's example... > SunOS 4: > % env TZ=GMT-4 date GMT-4 is a timezone file (Olson) > Thu Feb 10 04:29:42 GMT-0400 1994 > % env TZ=GMT-04 date But use POSIX rules here > Thu Feb 10 12:32:21 GMT 1994 ...does POSIX *require* that the above rules be written > Zone GMT 0 - GMT > > ! Zone GMT+1200 -12 - GMT > ! Zone GMT+1100 -11 - GMT (that is, without the "+1200" modifier to the zone name that will appear in user-visible output)? --ado

3 2

Re: Standard for timezone handling with TZ
by eggert＠twinsun.com Feb. 10, 1994

Feb. 10, 1994

In comp.unix.solaris Casper H.S. Dik writes: > SunOS 4: > % env TZ=GMT-4 date GMT-4 is a timezone file (Olson) > Thu Feb 10 04:29:42 GMT-0400 1994 > % env TZ=GMT-04 date But use POSIX rules here > Thu Feb 10 12:32:21 GMT 1994 That's a bug in the Olson rules; they aren't compatible with Posix 1003.1-1990. Thanks for pointing it out. Here's a conservative patch to Olson's latest version which renames `GMT-4' to `GMT-0400' to avoid the bug. Another possibility is simply to remove the GMT[-+]* rules, since their sign is the opposite of the sign in the Posix TZ string, and this is confusing. *** etcetera 1992/04/23 17:34:35 7.1 --- etcetera 1994/02/10 19:49:45 7.1.1.1 *************** *** 6,55 **** Zone GMT 0 - GMT ! Zone GMT-12 -12 - GMT-1200 ! Zone GMT-11 -11 - GMT-1100 ! Zone GMT-10 -10 - GMT-1000 ! Zone GMT-9 -9 - GMT-0900 ! Zone GMT-8 -8 - GMT-0800 ! Zone GMT-7 -7 - GMT-0700 ! Zone GMT-6 -6 - GMT-0600 ! Zone GMT-5 -5 - GMT-0500 ! Zone GMT-4 -4 - GMT-0400 ! Zone GMT-3 -3 - GMT-0300 ! Zone GMT-2 -2 - GMT-0200 ! Zone GMT-1 -1 - GMT-0100 ! Zone GMT+1 1 - GMT+0100 ! Zone GMT+2 2 - GMT+0200 ! Zone GMT+3 3 - GMT+0300 ! Zone GMT+4 4 - GMT+0400 ! Zone GMT+5 5 - GMT+0500 ! Zone GMT+6 6 - GMT+0600 ! Zone GMT+7 7 - GMT+0700 ! Zone GMT+8 8 - GMT+0800 ! Zone GMT+9 9 - GMT+0900 ! Zone GMT+10 10 - GMT+1000 ! Zone GMT+11 11 - GMT+1100 ! Zone GMT+12 12 - GMT+1200 ! Zone GMT+13 13 - GMT+1300 # GMT+12 with DST Link GMT UTC Link GMT UCT Link GMT Universal Link GMT Greenwich Link GMT Zulu ! Link GMT GMT-0 ! Link GMT GMT+0 ! Link GMT GMT0 ! Link GMT+1 GMT1 ! Link GMT+2 GMT2 ! Link GMT+3 GMT3 ! Link GMT+4 GMT4 ! Link GMT+5 GMT5 ! Link GMT+6 GMT6 ! Link GMT+7 GMT7 ! Link GMT+8 GMT8 ! Link GMT+9 GMT9 ! Link GMT+10 GMT10 ! Link GMT+11 GMT11 ! Link GMT+12 GMT12 ! Link GMT+13 GMT13 --- 6,41 ---- Zone GMT 0 - GMT ! Zone GMT-1200 -12 - GMT-1200 ! Zone GMT-1100 -11 - GMT-1100 ! Zone GMT-1000 -10 - GMT-1000 ! Zone GMT-0900 -9 - GMT-0900 ! Zone GMT-0800 -8 - GMT-0800 ! Zone GMT-0700 -7 - GMT-0700 ! Zone GMT-0600 -6 - GMT-0600 ! Zone GMT-0500 -5 - GMT-0500 ! Zone GMT-0400 -4 - GMT-0400 ! Zone GMT-0300 -3 - GMT-0300 ! Zone GMT-0200 -2 - GMT-0200 ! Zone GMT-0100 -1 - GMT-0100 ! Zone GMT+0100 1 - GMT+0100 ! Zone GMT+0200 2 - GMT+0200 ! Zone GMT+0300 3 - GMT+0300 ! Zone GMT+0400 4 - GMT+0400 ! Zone GMT+0500 5 - GMT+0500 ! Zone GMT+0600 6 - GMT+0600 ! Zone GMT+0700 7 - GMT+0700 ! Zone GMT+0800 8 - GMT+0800 ! Zone GMT+0900 9 - GMT+0900 ! Zone GMT+1000 10 - GMT+1000 ! Zone GMT+1100 11 - GMT+1100 ! Zone GMT+1200 12 - GMT+1200 ! Zone GMT+1300 13 - GMT+1300 # GMT+12 with DST Link GMT UTC Link GMT UCT Link GMT Universal Link GMT Greenwich Link GMT Zulu ! Link GMT GMT-0000 ! Link GMT GMT+0000

1 0

Re: zic.c:mkdirs broken
by ado Feb. 10, 1994

Feb. 10, 1994

> The fix I sent before for this never made it into 94b. I don't know how > this fails to break everyone else. mkdirs is broken unless you compile > with -fwritable-strings (which is generally losing to do). > ... Thanks for the fix; it (and only it) is incorporated into tzcode94c.tar.gz on elsie.nci.nih.gov. The relevant diff is attached below. --ado SCCS/s.zic.c: 7.21 vs. 7.22 *** 7.21/zic.c Thu Feb 10 08:54:03 1994 --- 7.22/zic.c Thu Feb 10 08:54:04 1994 *************** *** 1,6 **** #ifndef lint #ifndef NOID ! static char elsieid[] = "@(#)zic.c 7.21"; #endif /* !defined NOID */ #endif /* !defined lint */ --- 1,6 ---- #ifndef lint #ifndef NOID ! static char elsieid[] = "@(#)zic.c 7.22"; #endif /* !defined NOID */ #endif /* !defined lint */ *************** *** 1878,1890 **** } static int ! mkdirs(name) ! char * const name; { register char * cp; ! if ((cp = name) == NULL || *cp == '\0') return 0; while ((cp = strchr(cp + 1, '/')) != 0) { *cp = '\0'; #ifndef unix --- 1878,1892 ---- } static int ! mkdirs(argname) ! char * const argname; { + register char * name; register char * cp; ! if (argname == NULL || *argname == '\0') return 0; + cp = name = ecpyalloc(argname); while ((cp = strchr(cp + 1, '/')) != 0) { *cp = '\0'; #ifndef unix *************** *** 1906,1916 **** --- 1908,1920 ---- "%s: Can't create directory ", progname); (void) perror(name); + ifree(name); return -1; } } *cp = '/'; } + ifree(name); return 0; }

1 0

Re: zic.c:mkdirs broken
by Bradley White Feb. 9, 1994

Feb. 9, 1994

+ /* We must make a copy in case the + passed pointer is a read-only string. */ + char *name = ecpyalloc (argname); + if ((cp = name) == NULL || *cp == '\0') { + free (name); + return 0; + } ecpyalloc(x) [a.k.a. memcheck(icpyalloc(x))] cannot return 0. But, if you just want to program defensively, it is also good practice not to pass 0 to free(), despite what any standards might say. With the ialloc package you can achieve this via ifree(). Bradley

1 0

zic.c:mkdirs broken
by roland＠gnu.ai.mit.edu Feb. 9, 1994

Feb. 9, 1994

The fix I sent before for this never made it into 94b. I don't know how this fails to break everyone else. mkdirs is broken unless you compile with -fwritable-strings (which is generally losing to do). diff -u /home/gd3/roland/libc/time/zic.c.\~4\~ /home/gd3/roland/libc/time/zic.c --- /home/gd3/roland/libc/time/zic.c.~4~ Mon Feb 7 14:30:53 1994 +++ /home/gd3/roland/libc/time/zic.c Wed Feb 9 14:09:11 1994 @@ -1877,14 +1877,20 @@ charcnt += eitol(i); } + static int -mkdirs(name) -char * const name; +mkdirs(argname) +char * const argname; { register char * cp; + /* We must make a copy in case the + passed pointer is a read-only string. */ + char *name = ecpyalloc (argname); - if ((cp = name) == NULL || *cp == '\0') - return 0; + if ((cp = name) == NULL || *cp == '\0') { + free (name); + return 0; + } while ((cp = strchr(cp + 1, '/')) != 0) { *cp = '\0'; #ifndef unix @@ -1906,11 +1912,13 @@ "%s: Can't create directory ", progname); (void) perror(name); + free (name); return -1; } } *cp = '/'; } + free (name); return 0; } Diff exited abnormally with code 1 at Wed Feb 9 14:09:45

1 0

leap seconds [forwarded with permission from wollman@uvm-gen.emba.uvm.edu]
by ado Feb. 7, 1994

Feb. 7, 1994

> From wollman(a)uvm-gen.EMBA.UVM.EDU Sun Feb 6 17:45:52 1994 > Return-Path: <wollman(a)uvm-gen.EMBA.UVM.EDU> > Received: from bajoran.emba.uvm.edu by elsie.nci.nih.gov (4.1/SMI-4.1) > id AA18437; Sun, 6 Feb 94 17:45:51 EST > Received: by bajoran.emba.uvm.edu id AA18471 > (5.65/6.05); Sun, 6 Feb 94 17:45:50 -0500 > Date: Sun, 6 Feb 94 17:45:50 -0500 > From: wollman(a)uvm-gen.EMBA.UVM.EDU > Message-Id: <9402062245.AA18471(a)bajoran.emba.uvm.edu> > To: ado(a)elsie.nci.nih.gov > Subject: Re: timezone servers > Newsgroups: comp.protocols.time.ntp > In-Reply-To: <1994Feb4.234532.26832(a)alw.nih.gov> > References: <199402020109.AA01671(a)ni.umd.edu> > Organization: University of Vermont, EMBA Computer Facility > > ...According to the bulletins that I've seen, |TAI-UTC| is about > 28 seconds now. However, the leapseconds file only lists 19 steps. > This is probably due to the fact that the first step was 10 seconds, > not just 1. Is there an easy way to fix this, so my users who use NTP > don't complain about their clocks being nine seconds off? > > -GAWollman > -- > Garrett A. Wollman | Shashish is simple, it's discreet, it's brief. ... > wollman(a)emba.uvm.edu | Shashish is the bonding of hearts in spite of distance. > NB: Address soon to | It is a bond more powerful than absence. We like people > be changed. | who like Shashish. - Claude McKenzie + Florent Vollant

4 3

tzcode94b.tar.gz and tzdata94b.tar.gz
by ado Feb. 7, 1994

Feb. 7, 1994

Updated time zone code and data is available by anonymous ftp from elsie.nci.nih.gov (128.231.16.1) in the "pub" directory; the culprits are -rw-r--r-- 1 ado 62145 Feb 7 10:04 tzcode94b.tar.gz -rw-r--r-- 1 ado 63993 Feb 7 10:04 tzdata94b.tar.gz The updates are the work by Paul Eggert (eggert(a)twinsun.com) who notes: > I found another book of time zone histories by E W Whitman; it's not as > extensive as Shanks but has a few goodies of its own. I used it to > update the tables. I also fixed some more as a result of > correspondence with Adam David and Peter Ilieve, and move some stray > links from `europe' to `backward'. I corrected some scanning errors in > usno1989. > > As far as the code goes, I fixed zic to allow years in the range > INT_MIN to INT_MAX; this fixed a few boundary conditions around 1900. > And I cleaned up the zic documentation a little bit. --ado

1 0

tzdata94a.tar.gz
by ado Feb. 3, 1994

Feb. 3, 1994

tzdata94a.tar.gz is now available on elsie.nci.nih.gov; it simply incorporates the recently announced leap second into the "leapseconds" file. For those who want to forego a trip to the ftp well, a diff from the previous version is attached. --ado SCCS/s.leapseconds: 7.6 vs. 7.7 *** 7.6/leapseconds Thu Feb 3 09:02:22 1994 --- 7.7/leapseconds Thu Feb 3 09:02:22 1994 *************** *** 1,4 **** ! # @(#)leapseconds 7.6 # Allowance for leapseconds added to each timezone file. --- 1,4 ---- ! # @(#)leapseconds 7.7 # Allowance for leapseconds added to each timezone file. *************** *** 38,40 **** --- 38,41 ---- 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

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time zones [forwarded with permission]
by ado Jan. 5, 1994

Jan. 5, 1994

> From ncm(a)netcom.com Wed Jan 5 03:20:09 1994 > Return-Path: <ncm(a)netcom.com> > Received: from mail.netcom.com (netcom3.netcom.com) by elsie.nci.nih.gov (4.1/SMI-4.1) > id AA17468; Wed, 5 Jan 94 03:20:07 EST > Received: from localhost by mail.netcom.com (8.6.4/SMI-4.1/Netcom) > id AAA02279; Wed, 5 Jan 1994 00:20:40 -0800 > Date: Wed, 5 Jan 1994 00:20:40 -0800 > From: ncm(a)netcom.com (Nathan Myers) > Message-Id: <199401050820.AAA02279(a)mail.netcom.com> > To: ado(a)elsie.nci.nih.gov > Subject: time zones > Status: RO > > Hello, > > I have been working on time zones at Rogue Wave Software, and > on locale support for the ISO/ANSI C++ Standard Library committee. > It seems to me that the C++ Library effort offers an excellent > place to standardize on a time zone library, as the contents > of a class timezone. We are not bound to C Library facilities > or conventions, so this is an opportunity to correct old mistakes. > (e.g. hidden static variables implied by the interface) > > Please forward this to anyone you think might be interested in > helping put together a proposal. > > Thank you > Nathan Myersn > myersn(a)roguewave.com

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Re: Iceland's timezone
by Adam David Dec. 9, 1993

Dec. 9, 1993

> # time the norsemen first settled Iceland. The first day of winter is always > # Saturday, but is not dependent on the Julian or Gregorian calendars. I will try and find a general rule for this, but it may take awhile. > # We go with the Almanak, except for two claims from Shanks: > # 1. In 1968 standard time wasn't switched to GMT until Oct 27; > # this affects only the time zone name and dst flag. I wonder if this one is such a good idea. Here is the actual quote from the almanak (paraphrased): In the year 1968 "summer time" was finally made standard time in Iceland by law number 6 from April 5th that year. The change was made on April 7th at 2:00 GMT and the clock was adjusted forwards by one hour. Clock time in Iceland has since then been on GMT the whole year round. Of course, both Shanks and the Almanak have the same actual time offset for summer 1968, but technically it is the Almanak that is correct. Shanks chooses October 27th as the transition time because that is when the end of the summer time would otherwise have been (by the previous general rule). -- Adam David <adam(a)veda.is>

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Iceland's timezone
by yata!eggert＠twinsun.com Dec. 9, 1993

Dec. 9, 1993

Thanks for looking up the U of Iceland Almanak. Here's how I translated what you wrote into tzfile format; I'll include this in the next set of revisions that I propose to ado. # Iceland # # From Adam David <adam(a)veda.is> (November 6, 1993): # The name of the timezone in Iceland for system / mail / news purposes is GMT. # # (December 5, 1993): # This material is paraphrased from the 1988 edition of the University of # Iceland Almanak. # # From January 1st, 1908 the whole of Iceland was standardised at 1 hour # behind GMT. Previously, local mean solar time was used in different parts # of Iceland, the almanak had been based on Reykjavik mean solar time which # was 1 hour and 28 minutes behind GMT. # # "first day of winter" referred to [below] means the first day of the 26 weeks # of winter, according to the old icelandic calendar that dates back to the # time the norsemen first settled Iceland. The first day of winter is always # Saturday, but is not dependent on the Julian or Gregorian calendars. # # From Paul Eggert <eggert(a)twinsun.com> (December 9, 1993): # The Iceland Almanak, Shanks and Whitman disagree on many points. # We go with the Almanak, except for two claims from Shanks: # 1. In 1968 standard time wasn't switched to GMT until Oct 27; # this affects only the time zone name and dst flag. # 2. Reykavik was -1:28 from 1837 to 1908, local mean time before that. # # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Iceland 1908 only - Jan 1 0:00 0 S Rule Iceland 1917 1918 - Feb 19 23:00 1:00 D Rule Iceland 1917 only - Oct 21 1:00 0 S Rule Iceland 1918 only - Nov 16 1:00 0 S Rule Iceland 1939 only - Apr 29 23:00 1:00 D Rule Iceland 1939 only - Nov 29 2:00 0 S Rule Iceland 1940 only - Feb 25 2:00 1:00 D Rule Iceland 1940 only - Nov 3 2:00 0 S Rule Iceland 1941 only - Mar 2 1:00s 1:00 D Rule Iceland 1941 only - Nov 2 1:00s 0 S Rule Iceland 1942 only - Mar 8 1:00s 1:00 D Rule Iceland 1942 only - Oct 25 1:00s 0 S # 1943-1946 - first Sunday in March until first Sunday in winter Rule Iceland 1943 1946 - Mar Sun>=1 1:00s 1:00 D Rule Iceland 1943 1948 - Oct Sun>=22 1:00s 0 S # 1947-1967 - first Sunday in April until first Sunday in winter Rule Iceland 1947 1968 - Apr Sun>=1 1:00s 1:00 D # 1949 Oct transition delayed by 1 week Rule Iceland 1949 only - Oct 30 1:00s 0 S Rule Iceland 1950 1966 - Oct Sun>=22 1:00s 0 S Rule Iceland 1967 only - Oct 29 1:00s 0 S # Zone NAME GMTOFF RULES FORMAT [UNTIL] Zone Atlantic/Reykjavik -1:27:24 - LMT 1837 -1:28 - RMT 1908 # Reykjavik Mean Time -1:00 Iceland I%sT 1968 Oct 27 1:00s 0:00 - GMT

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Re: Iceland's timezone
by Adam David Dec. 6, 1993

Dec. 6, 1993

Sorry about the delay getting back with this information. > I'm working on a rewrite of `europe' with a large set of historical > data. My current draft (see below) claims that Iceland changed its > timezone in 1968. I've taken this claim from Thomas G. Shanks, The > international atlas (3rd edition), San Diego: ACS Publications, Inc. > (1991). If you have some better data, please let me know. In a way, there was a timezone change in 1968, where the summertime change was applied during the spring, and became the all-year-round time, and there have been no changes since then, not for DST or any other reason. When looking back to previous years when there was DST, icelanders tend to refer to the concept of "winter time", as the summer time had the same offset as the present all-year-round time. This is why I was led to believe that no timezone change had taken place in 1968. > It would be nice to know what time zone abbreviations were used before > 1968, since Shanks doesn't say. In the following table I've made up > the names `IST', `IDT', `RMT', and `LMT' for Iceland Standard Time, > Iceland Daylight Time, Reykjavik Mean Time, and Local Mean Time > respectively. I have no details of any abbreviations, sorry. > # From Shanks (1991): > # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S > Rule Iceland 1908 only - Jan 1 0:00 0 S > Rule Iceland 1917 1918 - Feb 20 2:00 1:00 D > Rule Iceland 1917 only - Oct 25 2:00 0 S > Rule Iceland 1918 1919 - Nov 15 2:00 0 S > Rule Iceland 1919 only - Feb 19 2:00 1:00 D > Rule Iceland 1921 only - Mar 19 2:00 1:00 D > Rule Iceland 1921 only - Jun 22 2:00 0 S > Rule Iceland 1941 1942 - Mar Sat>=1 2:00 1:00 D > Rule Iceland 1941 1942 - Jul 2 2:00 0 S > Rule Iceland 1943 1946 - Mar Sun>=1 2:00 1:00 D > Rule Iceland 1943 1948 - Oct Sun>=22 2:00 0 S > Rule Iceland 1947 1962 - Apr Sun>=1 2:00 1:00 D > Rule Iceland 1949 only - Oct 30 2:00 0 S > Rule Iceland 1950 only - Oct 22 2:00 0 S > # From Paul Eggert <eggert(a)twinsun.com> (November 10, 1993): > # Shanks's ``1953 Oct 26'' is probably a typo for Oct 25. > # Likewise, correct Shanks's ``1961 Oct 22'' to Oct 29. > Rule Iceland 1951 1967 - Oct Sun>=23 1:00s 0 S > Rule Iceland 1963 1968 - Apr Sun>=1 1:00s 1:00 D > # Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL] > Zone Atlantic/Iceland/Reykjavik -1:27:24 - LMT 1837 Jan 1 > -1:28 - RMT 1908 Jan 1 > -1:00 Iceland I%sT 1968 Oct 27 1:00s > 0:00 - GMT > # This link is for backward compatibility with the old naming convention. > Link Atlantic/Iceland/Reykjavik Iceland I don't feel up to messing with this table and submitting a corrected version. Here I copy a list of periods when summertime was active, and explanatory text. This material is paraphrased from the 1988 edition of the University of Iceland Almanak. >From January 1st, 1908 the whole of Iceland was standardised at 1 hour behind GMT. Previously, local mean solar time was used in different parts of Iceland, the almanak had been based on Reykjavik mean solar time which was 1 hour and 28 minutes behind GMT. Summertime when it was applied was always by putting the clock an hour forward during the summer months, which made the clock time equal to GMT. The following list shows when this summertime was in force. The time of the clock change is specified in GMT. year from to ---- ---- -- 1908-1916 no summertime 1917 20.Feb. 0:00 21.Oct. 1:00 1918 20.Feb. 0:00 16.Nov. 1:00 1919-1938 no summertime 1939 30.Apr. 0:00 29.Nov. 2:00 1940 25.Feb. 3:00 3.Nov. 2:00 1941 2.Mar. 2:00 2.Nov. 2:00 1942 8.Mar. 2:00 25.Oct. 2:00 1943-1946 rule (first Sunday in March until first Sunday in winter) 1943 7.Mar. 2:00 24.Oct. 2:00 1944 5.Mar. 2:00 22.Oct. 2:00 1945 4.Mar. 2:00 28.Oct. 2:00 1946 3.Mar. 2:00 27.Oct. 2:00 1947-1967 rule (first Sunday in April until first Sunday in winter) 1947 6.Apr. 2:00 26.Oct. 2:00 1948 4.Apr. 2:00 24.Oct. 2:00 1949 3.Apr. 2:00 ******* 30.Oct. 2:00 (delayed by 1 week) 1950 2.Apr. 2:00 22.Oct. 2:00 1951 1.Apr. 2:00 28.Oct. 2:00 1952 6.Apr. 2:00 26.Oct. 2:00 1953 5.Apr. 2:00 25.Oct. 2:00 1954 4.Apr. 2:00 24.Oct. 2:00 1955 3.Apr. 2:00 23.Oct. 2:00 1956 1.Apr. 2:00 28.Oct. 2:00 1957 7.Apr. 2:00 27.Oct. 2:00 1958 6.Apr. 2:00 26.Oct. 2:00 1959 5.Apr. 2:00 25.Oct. 2:00 1960 3.Apr. 2:00 23.Oct. 2:00 1961 2.Apr. 2:00 22.Oct. 2:00 1962 1.Apr. 2:00 28.Oct. 2:00 1963 7.Apr. 2:00 27.Oct. 2:00 1964 5.Apr. 2:00 25.Oct. 2:00 1965 4.Apr. 2:00 24.Oct. 2:00 1966 3.Apr. 2:00 23.Oct. 2:00 1967 2.Apr. 2:00 29.Oct. 2:00 1968 7.Apr. 2:00 (actually GMT after this) "first day of winter" referred to above, means the first day of the 26 weeks of winter, according to the old icelandic calendar that dates back to the time the norsemen first settled Iceland. The first day of winter is always Saturday, but is not dependent on the Julian or Gregorian calendars. This is the reason for the discrepancy with October 1961. I can find out more exactly how to determine when it falls, if necessary. It is a pity I don't have that information handy, otherwise I could include it here. There are more serious discrepancies before 1941 which are not obviously explainable. What to do... (?) -- Adam David <adam(a)veda.is>

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Re: Timezone rule change in Europe [forwarded from Dik Winter]
by Dik.Winter＠cwi.nl Dec. 3, 1993

Dec. 3, 1993

> Has anyone got precise details of the dates? i.e last sunday in october, or > last sunday after 23rd October (like uk) The paper was a bit unclear about that; the text was conflicting. On the one hand it talked about the current UK rule, on the other hand it talked about the last sunday in October. But I presume the rule now valid in the UK will be adopted by the remainder of the EU. So that would be first sunday after 23rd October. I will report about it when I know more. dik

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Re: Timezone rule change in Europe [forwarded from Dik Winter]
by Glenn.Wright＠UK.Sun.COM Dec. 3, 1993

Dec. 3, 1993

Has anyone got precise details of the dates? i.e last sunday in october, or last sunday after 23rd October (like uk) Glenn. > > The ministers of transport of the European Union (formerly European > Community) have decided that by 1997 change from summer time to > winter time will be made by the end of october instead of the end > of september. This will bring the remainder of the EU in line with > the current rule in the United Kingdom and Ireland. It is to be expected > that other European countries will follow. [This according of my > paper of todaty, December 1.] > > (The European Union consists of: Netherlands, Belgium, Luxembourg, > France, Germany, Italy, United Kingdom, Ireland, Danmark, Spain, > Portugal and Greece.)

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Timezone rule change in Europe [forwarded from Dik Winter]
by ado Dec. 2, 1993

Dec. 2, 1993

> From daemon(a)ncifcrf.gov Thu Dec 2 13:51:20 1993 > Return-Path: <daemon(a)ncifcrf.gov> > Received: from fcs280s.ncifcrf.gov by elsie (4.1/SMI-4.1) > id AA12625; Thu, 2 Dec 93 13:51:19 EST > Received: by fcs280s.ncifcrf.gov (4.1/NCIFCRF-3.0/AWF-2.0) > id AA04025; Thu, 2 Dec 93 13:43:34 GMT > Received: from charon.cwi.nl by fcs280s.ncifcrf.gov (4.1/NCIFCRF-3.0/AWF-2.0) > id AA04003; Thu, 2 Dec 93 13:43:28 GMT > Received: from boring.cwi.nl by charon.cwi.nl with SMTP > id AA02005 (5.65b/3.12/CWI-Amsterdam); Wed, 1 Dec 1993 22:07:42 +0100 > Received: by boring.cwi.nl > id AA12403 (4.1/2.10/CWI-Amsterdam); Wed, 1 Dec 93 22:07:42 +0100 > Date: Wed, 1 Dec 93 22:07:42 +0100 > From: Dik.Winter(a)cwi.nl > Message-Id: <9312012107.AA12403.dik(a)boring.cwi.nl> > To: ado(a)ncifcrf.gov > Subject: Timezone rule change in Europe > Status: RO > > The ministers of transport of the European Union (formerly European > Community) have decided that by 1997 change from summer time to > winter time will be made by the end of october instead of the end > of september. This will bring the remainder of the EU in line with > the current rule in the United Kingdom and Ireland. It is to be expected > that other European countries will follow. [This according of my > paper of todaty, December 1.] > > (The European Union consists of: Netherlands, Belgium, Luxembourg, > France, Germany, Italy, United Kingdom, Ireland, Danmark, Spain, > Portugal and Greece.) > > dik > -- > dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland > home: bovenover 215, 1025 jn amsterdam, nederland; e-mail: dik(a)cwi.nl

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tzcode93g.tar.gz and tzdata93g.tar.gz
by ado Nov. 29, 1993

Nov. 29, 1993

The files tzcode93g.tar.gz and tzdata93g.tar.gz are now available for anonymous ftp from the ~ftp/pub directory on elsie.nci.nih.gov (128.231.16.1). Paul Eggert has provided a good deal of historic information (based on Shanks), and there are some code changes to deal with the buglets that crawled out in dealing with the new information. --ado

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Iceland's timezone
by yata!eggert＠twinsun.com Nov. 11, 1993

Nov. 11, 1993

From: Adam David <adam(a)veda.is> To: wollman(a)uvm-gen.emba.uvm.edu Date: Sat, 6 Nov 1993 21:50:43 +0000 (GMT) Iceland has not changed timezone since 1900 and has not had Summer Time since quite a long time ago, probably before 1970. If you want exact dates for summertime that long ago, I will find this out for you. I'm working on a rewrite of `europe' with a large set of historical data. My current draft (see below) claims that Iceland changed its timezone in 1968. I've taken this claim from Thomas G. Shanks, The international atlas (3rd edition), San Diego: ACS Publications, Inc. (1991). If you have some better data, please let me know. It would be nice to know what time zone abbreviations were used before 1968, since Shanks doesn't say. In the following table I've made up the names `IST', `IDT', `RMT', and `LMT' for Iceland Standard Time, Iceland Daylight Time, Reykjavik Mean Time, and Local Mean Time respectively. # Iceland # # From Adam David <adam(a)veda.is> (November 6, 1993): # The name of the timezone in Iceland for system / mail / news purposes is GMT. # # From Shanks (1991): # Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S Rule Iceland 1908 only - Jan 1 0:00 0 S Rule Iceland 1917 1918 - Feb 20 2:00 1:00 D Rule Iceland 1917 only - Oct 25 2:00 0 S Rule Iceland 1918 1919 - Nov 15 2:00 0 S Rule Iceland 1919 only - Feb 19 2:00 1:00 D Rule Iceland 1921 only - Mar 19 2:00 1:00 D Rule Iceland 1921 only - Jun 22 2:00 0 S Rule Iceland 1941 1942 - Mar Sat>=1 2:00 1:00 D Rule Iceland 1941 1942 - Jul 2 2:00 0 S Rule Iceland 1943 1946 - Mar Sun>=1 2:00 1:00 D Rule Iceland 1943 1948 - Oct Sun>=22 2:00 0 S Rule Iceland 1947 1962 - Apr Sun>=1 2:00 1:00 D Rule Iceland 1949 only - Oct 30 2:00 0 S Rule Iceland 1950 only - Oct 22 2:00 0 S # From Paul Eggert <eggert(a)twinsun.com> (November 10, 1993): # Shanks's ``1953 Oct 26'' is probably a typo for Oct 25. # Likewise, correct Shanks's ``1961 Oct 22'' to Oct 29. Rule Iceland 1951 1967 - Oct Sun>=23 1:00s 0 S Rule Iceland 1963 1968 - Apr Sun>=1 1:00s 1:00 D # Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL] Zone Atlantic/Iceland/Reykjavik -1:27:24 - LMT 1837 Jan 1 -1:28 - RMT 1908 Jan 1 -1:00 Iceland I%sT 1968 Oct 27 1:00s 0:00 - GMT # This link is for backward compatibility with the old naming convention. Link Atlantic/Iceland/Reykjavik Iceland

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Re: Specifications for Iceland's timezone [forwarded]
by ado Nov. 9, 1993

Nov. 9, 1993

> From wollman(a)uvm-gen.EMBA.UVM.EDU Sat Nov 6 17:01:21 1993 > Return-Path: <wollman(a)uvm-gen.EMBA.UVM.EDU> > Received: from sadye.emba.uvm.edu by elsie.nci.nih.gov (4.1/SMI-4.1) > id AA20235; Sat, 6 Nov 93 17:01:19 EST > Received: by sadye.emba.uvm.edu id AA06301 > (5.65/1.23); Sat, 6 Nov 93 17:00:22 -0500 > Date: Sat, 6 Nov 93 17:00:22 -0500 > From: wollman(a)uvm-gen.EMBA.UVM.EDU > Message-Id: <9311062200.AA06301(a)sadye.emba.uvm.edu> > To: ado(a)elsie.nci.nih.gov > Subject: Specifications for Iceland's timezone > Status: RO > > One of the FreeBSD team members in Iceland reports the following > complaints with the default `Iceland' timezone as supplied in your > latest `europe' file: > > ------- Start of forwarded message ------- > From: Adam David <adam(a)veda.is> > To: wollman(a)uvm-gen.emba.uvm.edu > Subject: Re: New timezone code > Date: Sat, 6 Nov 1993 21:50:43 +0000 (GMT) > > [stuff deleted by me -GW] > > The problem with WET is that WET is used also in the British Isles, and > some systems might assume BST by default if they see "WET" during the summer > months. The name of the timezone in Iceland for system / mail / news purposes > is GMT. [...] > > > If Iceland has ever observed Summer Time or has changed time > > zones at any time in the past, I'd appreciate knowing about it, so we > > can update the files and send the corrections to Arthur David Olson. > > Iceland has not changed timezone since 1900 and has not had Summer Time > since quite a long time ago, probably before 1970. If you want exact dates > for summertime that long ago, I will find this out for you. > > [...] > ------- End of forwarded message ------- > > -GAWollman > > -- > Garrett A. Wollman | Shashish is simple, it's discreet, it's brief. ... > wollman(a)emba.uvm.edu | Shashish is the bonding of hearts in spite of distance. > uvm-gen!wollman | It is a bond more powerful than absence. We like people > UVM disagrees. | who like Shashish. - Claude McKenzie + Florent Vollant

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possible time zone file syntax extension
by ado Nov. 5, 1993

Nov. 5, 1993

There's work in progress on adding historical information to time zone files. It might be useful to extend the syntax of "UNTIL" parts so that you could write something such as # Zone NAME GMTOFF RULES/SAVE FORMAT [UNTIL] Zone This 0:00 - TST 1916 May 21 2:00s 0:00 Whatever T%sT 1968 Feb 18 2:00s->That where the "->That" on the final line means "after the UNTIL time, use whatever happens in Zone 'That'." This would both allow for more concise representation of historic information and allow a "-c" (or some other letter) flag to zic that would tell it to only compile "current" zones--zones that did NOT end with a line containing "->". If you have insights on whether this is the best thing to do, I'd love it if you'd share them with folks on the time zone mailing list. --ado

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proposal for time zone names
by eggert＠twinsun.com Oct. 20, 1993

Oct. 20, 1993

I thought a bit about the problem of the explosion of time zone names, since we're looking at time zone rules for everywhere from Afghanistan to Zimbabwe. What do people think about time zone names of the from MAJOR_REGION/COUNTRY/CITY, e.g.: Africa/Zimbabwe/Harare Asia/Afghanistan/Kabul Europe/Albania/Tirana North_America/US/Los_Angeles Pacific/Fiji/Suva The ``major regions'' would be continents (Africa, North_ and South_ America, Antarctica, Australia, Asia, Europe) and oceans (Antarctic, Artic, Atlantic, Indian, Pacific). The ``minor regions'' would typically be countries. Only present-day English names for regions and cities would be used. The advantage of going to the detail of CITY is that we can use local mean time for times before standard time was introduced (e.g. before 1914 Jan 1 in Albania); this increases the accuracy of the database. Of course we should maintain links to traditional names like `Japan' and `US/Eastern' for backwards compatibility. Since I last wrote, I've coded up two sample countries. Asia/Afghanistan/Kabul needed just two lines of rules; Shanks says they've changed the rules only once since they adopted standard time in 1890. Europe/Albania/Tirana is a much more complicated 35-liner. Not only did it suffer the time zone vagaries of World War II, but also its dictatorship fiddled with the clocks seemingly at random between 1974 and 1984 before finally switching to the Polish rules. It looks like this will take some time.

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