October 1995 - tz - lists.iana.org

Re: Reentrant versions of localtime and gmtime.
by Joel.Tornatore＠Eng.Sun.COM Oct. 31, 1995

Oct. 31, 1995

## From eggert(a)twinsun.com Mon Oct 30 20:06:39 1995 ## ## Date: Mon, 30 Oct 1995 17:13:53 -0800 ## From: "J.T. Conklin" <jtc(a)cygnus.com> ## ## struct tm * ## + localtime_r(timep, res) ## + const time_t * const timep; ## + struct tm * tm; ## + { ## + tzset(); ## + localsub(timep, 0L, tm); ## + return tm; ## + } ## ## That isn't reentrant, since tzset() isn't reentrant. Solaris solves this problem with a mutex lock that is acquired by all functions, including the _r versions. joel

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Reentrant versions of localtime and gmtime.
by J.T. Conklin Oct. 30, 1995

Oct. 30, 1995

Thread-safe programming needs reentrant versions of some of the time functions. The following patch adds localtime_r and gmtime_r a'la Solaris (The Solaris manpage mentiones that these are taken from a POSIX draft, but I don't have a copy to double check). Although it is possible to write localtime and gmtime in terms of the new functions, I decided not to because they are so trival. The Solaris manpage also mentions ctime_r and asctime_r. I'll submit those later tonight. --jtc *** OLD/localtime.c Mon Oct 30 17:00:52 1995 --- localtime.c Mon Oct 30 17:03:48 1995 *************** *** 1026,1031 **** --- 1026,1041 ---- } struct tm * + localtime_r(timep, res) + const time_t * const timep; + struct tm * tm; + { + tzset(); + localsub(timep, 0L, tm); + return tm; + } + + struct tm * localtime(timep) const time_t * const timep; { *************** *** 1072,1077 **** --- 1082,1096 ---- #endif /* State Farm */ } #endif /* defined TM_ZONE */ + } + + struct tm * + gmtime_r(timep, tm) + const time_t * const timep; + struct tm * tm; + { + gmtsub(timep, 0L, tm); + return tm; } struct tm *

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Question about reentrant ctime and asctime
by J.T. Conklin Oct. 30, 1995

Oct. 30, 1995

In my previous message, I mentioned that I'd submit versions of asctime_r and ctime_r later this evening. However, I discovered that most systems declare these as: int asctime_r (const struct tm *, char *, int); int ctime_r (const time_t *, char *, int); while Solaris provides: char *asctime_r (const struct tm *, char *, int); char *ctime_r (const time_t *, char *, int); *AND* char *asctime_r (const struct tm *, char *) char *ctime_r (const time_t *, char *); Naturally I'd like to implement the interface standardized by whatever POSIX standard covers this (realtime?, threads?). If someone with the appropriate standards document could point out the correct interface, please let me know. --jtc

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Re: tz 8-bit-clean proposed patch
by ado Oct. 30, 1995

Oct. 30, 1995

The (slightly reformatted) "8-bit-clean proposed patch" and the "tz minor patch: US/Eastern -> America/New_York" have been incorporated into... -rw-r--r-- 1 ado 69206 Oct 30 10:40 tzcode95g.tar.gz -rw-r--r-- 1 ado 69838 Oct 30 10:40 tzdata95k.tar.gz in elsie.nci.nih.gov's ~ftp/pub directory, along with a snapshot of the USNO's latest data ("usno1995") and some other minor cleanups. --ado

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tz minor patch: US/Eastern -> America/New_York
by Paul Eggert Oct. 29, 1995

Oct. 29, 1995

Some tz comments refer to US/Eastern, but it is present only if the `backward' file is used. Here is a proposed patch. =================================================================== RCS file: RCS/Theory,v retrieving revision 1995.3 retrieving revision 1995.3.1.1 diff -c -r1995.3 -r1995.3.1.1 *** Theory 1993/11/22 20:23:18 1995.3 --- Theory 1995/10/30 01:50:47 1995.3.1.1 *************** *** 47,53 **** abbreviations are used. It was recognized that allowing the "TZ" environment variable to ! take on values such as "US/Eastern" might cause "old" programs (that expect "TZ" to have a certain form) to operate incorrectly; consideration was given to using some other environment variable (for example, "TIMEZONE") to hold the string used to generate the --- 47,53 ---- abbreviations are used. It was recognized that allowing the "TZ" environment variable to ! take on values such as "America/New_York" might cause "old" programs (that expect "TZ" to have a certain form) to operate incorrectly; consideration was given to using some other environment variable (for example, "TIMEZONE") to hold the string used to generate the =================================================================== RCS file: RCS/date.c,v retrieving revision 1995.3.1.1 retrieving revision 1995.3.1.2 diff -c -r1995.3.1.1 -r1995.3.1.2 *** date.c 1995/10/30 00:43:48 1995.3.1.1 --- date.c 1995/10/30 01:50:47 1995.3.1.2 *************** *** 207,215 **** if ((cp = strchr(value, '.')) != NULL) { /* ** Ensure that the failure of ! ** TZ=US/Eastern date 8712312359.60 ** doesn't get misdiagnosed. (It was ! ** TZ=US/Eastern date 8712311859.60 ** when the leap second was inserted.) ** The normal check won't work since ** the given time is valid in GMT. --- 207,215 ---- if ((cp = strchr(value, '.')) != NULL) { /* ** Ensure that the failure of ! ** TZ=America/New_York date 8712312359.60 ** doesn't get misdiagnosed. (It was ! ** TZ=America/New_York date 8712311859.60 ** when the leap second was inserted.) ** The normal check won't work since ** the given time is valid in GMT. =================================================================== RCS file: RCS/zic.8,v retrieving revision 1995.3 retrieving revision 1995.3.1.1 diff -c -r1995.3 -r1995.3.1.1 *** zic.8 1995/03/11 17:55:51 1995.3 --- zic.8 1995/10/30 01:50:47 1995.3.1.1 *************** *** 324,336 **** .nf .ti +.5i .if t .ta \w'Link\0\0'u +\w'LINK-FROM\0\0'u ! .if n .ta \w'Link\0\0'u +\w'US/Eastern\0\0'u Link LINK-FROM LINK-TO .sp For example: .sp .ti +.5i ! Link US/Eastern EST5EDT .sp .fi The --- 324,336 ---- .nf .ti +.5i .if t .ta \w'Link\0\0'u +\w'LINK-FROM\0\0'u ! .if n .ta \w'Link\0\0'u +\w'America/New_York\0\0'u Link LINK-FROM LINK-TO .sp For example: .sp .ti +.5i ! Link America/New_York US/Eastern .sp .fi The

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tz 8-bit-clean proposed patch
by Paul Eggert Oct. 29, 1995

Oct. 29, 1995

In a few places the tz code assumes that characters are nonnegative. The tz code uses `isascii' to avoid this problem sometimes, but not always, and anyway `isascii' isn't portable to some hosts that have strict ANSI or Posix checking turned on, since isascii is not required by either the C Standard or Posix. Here is a proposed patch that handles top-bit-on characters correctly in all the places where I found this problem. The patch is portable to hosts that don't define isascii. The proposed patch also removes a few unnecessary tests, and changes one call to ciequal to invoke strcmp, since the argument string has no alphabetic characters in it. =================================================================== RCS file: RCS/private.h,v retrieving revision 1995.3 retrieving revision 1995.3.1.1 diff -c -r1995.3 -r1995.3.1.1 *** private.h 1995/03/11 17:55:53 1995.3 --- private.h 1995/10/30 00:43:48 1995.3.1.1 *************** *** 47,53 **** #include "sys/types.h" /* for time_t */ #include "stdio.h" - #include "ctype.h" #include "errno.h" #include "string.h" #include "limits.h" /* for CHAR_BIT */ --- 47,52 ---- *************** *** 66,71 **** --- 65,73 ---- #define R_OK 4 #endif /* !defined R_OK */ #endif /* !(HAVE_UNISTD_H - 0) */ + + /* Unlike <ctype.h>'s isdigit, this also works if c < 0 | c > UCHAR_MAX. */ + #define is_digit(c) ((unsigned)(c) - '0' <= 9) /* ** Workarounds for compilers/systems. =================================================================== RCS file: RCS/date.c,v retrieving revision 1995.3 retrieving revision 1995.3.1.1 diff -c -r1995.3 -r1995.3.1.1 *** date.c 1995/03/11 17:55:47 1995.3 --- date.c 1995/10/30 00:43:48 1995.3.1.1 *************** *** 459,465 **** nondigit(cp) register const char * cp; { ! while (isdigit(*cp)) ++cp; return cp; } --- 459,465 ---- nondigit(cp) register const char * cp; { ! while (is_digit(*cp)) ++cp; return cp; } *************** *** 592,598 **** dotp = strchr(value, '.'); for (cp = value; *cp != '\0'; ++cp) ! if (!isdigit(*cp) && cp != dotp) wildinput("time", value, "contains a nondigit"); if (dotp == NULL) --- 592,598 ---- dotp = strchr(value, '.'); for (cp = value; *cp != '\0'; ++cp) ! if (!is_digit(*cp) && cp != dotp) wildinput("time", value, "contains a nondigit"); if (dotp == NULL) =================================================================== RCS file: RCS/localtime.c,v retrieving revision 1995.6 retrieving revision 1995.6.1.1 diff -c -r1995.6 -r1995.6.1.1 *** localtime.c 1995/10/28 16:09:02 1995.6 --- localtime.c 1995/10/30 00:43:48 1995.6.1.1 *************** *** 415,421 **** { register char c; ! while ((c = *strp) != '\0' && !isdigit(c) && c != ',' && c != '-' && c != '+') ++strp; return strp; --- 415,421 ---- { register char c; ! while ((c = *strp) != '\0' && !is_digit(c) && c != ',' && c != '-' && c != '+') ++strp; return strp; *************** *** 438,452 **** register char c; register int num; ! if (strp == NULL || !isdigit(*strp)) return NULL; num = 0; ! while ((c = *strp) != '\0' && isdigit(c)) { num = num * 10 + (c - '0'); if (num > max) return NULL; /* illegal value */ ! ++strp; ! } if (num < min) return NULL; /* illegal value */ *nump = num; --- 438,452 ---- register char c; register int num; ! if (strp == NULL || !is_digit(c = *strp)) return NULL; num = 0; ! do { num = num * 10 + (c - '0'); if (num > max) return NULL; /* illegal value */ ! c = *++strp; ! } while (is_digit(c)); if (num < min) return NULL; /* illegal value */ *nump = num; *************** *** 508,521 **** register const char * strp; long * const offsetp; { ! register int neg; if (*strp == '-') { neg = 1; ++strp; ! } else if (isdigit(*strp) || *strp++ == '+') ! neg = 0; ! else return NULL; /* illegal offset */ strp = getsecs(strp, offsetp); if (strp == NULL) return NULL; /* illegal time */ --- 508,520 ---- register const char * strp; long * const offsetp; { ! register int neg = 0; if (*strp == '-') { neg = 1; ++strp; ! } else if (*strp == '+') ! ++strp; strp = getsecs(strp, offsetp); if (strp == NULL) return NULL; /* illegal time */ *************** *** 560,566 **** if (*strp++ != '.') return NULL; strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1); ! } else if (isdigit(*strp)) { /* ** Day of year. */ --- 559,565 ---- if (*strp++ != '.') return NULL; strp = getnum(strp, &rulep->r_day, 0, DAYSPERWEEK - 1); ! } else if (is_digit(*strp)) { /* ** Day of year. */ =================================================================== RCS file: RCS/scheck.c,v retrieving revision 1994.8 retrieving revision 1994.8.1.1 diff -c -r1994.8 -r1994.8.1.1 *** scheck.c 1994/12/09 04:33:18 1994.8 --- scheck.c 1995/10/30 00:43:48 1994.8.1.1 *************** *** 42,48 **** *tp++ = '*'; if (*fp == '*') ++fp; ! while (isascii(*fp) && isdigit(*fp)) *tp++ = *fp++; if (*fp == 'l' || *fp == 'h') *tp++ = *fp++; --- 42,48 ---- *tp++ = '*'; if (*fp == '*') ++fp; ! while (is_digit(*fp)) *tp++ = *fp++; if (*fp == 'l' || *fp == 'h') *tp++ = *fp++; =================================================================== RCS file: RCS/zic.c,v retrieving revision 1995.6 retrieving revision 1995.6.1.1 diff -c -r1995.6 -r1995.6.1.1 *** zic.c 1995/10/28 20:51:12 1995.6 --- zic.c 1995/10/30 00:43:48 1995.6.1.1 *************** *** 10,15 **** --- 10,28 ---- #include "sys/stat.h" /* for umask manifest constants */ #endif /* defined unix */ + /* + ** On some ancient hosts, predicates like `isspace(C)' are defined + ** only if isascii(C) || C == EOF. Modern hosts obey the C Standard, + ** which says they are defined only if C == (unsigned char)C || C == EOF. + ** Neither the C Standard nor Posix require that `isascii' exist. + ** For portability, we check both ancient and modern requirements. + ** If isascii is not defined, the isascii check succeeds trivially. + */ + #include "ctype.h" + #ifndef isascii + #define isascii(x) 1 + #endif + struct rule { const char * r_filename; int r_linenum; *************** *** 721,727 **** while (fields[nfields] != NULL) { static char nada; ! if (ciequal(fields[nfields], "-")) fields[nfields] = &nada; ++nfields; } --- 734,740 ---- while (fields[nfields] != NULL) { static char nada; ! if (strcmp(fields[nfields], "-") == 0) fields[nfields] = &nada; ++nfields; } *************** *** 1702,1709 **** static int lowerit(a) ! const int a; { return (isascii(a) && isupper(a)) ? tolower(a) : a; } --- 1715,1723 ---- static int lowerit(a) ! int a; { + a = (unsigned char)a; return (isascii(a) && isupper(a)) ? tolower(a) : a; } *************** *** 1775,1781 **** emalloc((int) ((strlen(cp) + 1) * sizeof *array)); nsubs = 0; for ( ; ; ) { ! while (isascii(*cp) && isspace(*cp)) ++cp; if (*cp == '\0' || *cp == '#') break; --- 1789,1795 ---- emalloc((int) ((strlen(cp) + 1) * sizeof *array)); nsubs = 0; for ( ; ; ) { ! while (isascii(*cp) && isspace((unsigned char)*cp)) ++cp; if (*cp == '\0' || *cp == '#') break; *************** *** 1788,1795 **** ++dp; else error("Odd number of quotation marks"); } while (*cp != '\0' && *cp != '#' && ! (!isascii(*cp) || !isspace(*cp))); ! if (isascii(*cp) && isspace(*cp)) ++cp; *dp = '\0'; } --- 1802,1809 ---- ++dp; else error("Odd number of quotation marks"); } while (*cp != '\0' && *cp != '#' && ! (!isascii(*cp) || !isspace((unsigned char)*cp))); ! if (isascii(*cp) && isspace((unsigned char)*cp)) ++cp; *dp = '\0'; } *************** *** 1952,1959 **** /* ** DOS drive specifier? */ ! if (strlen(name) == 2 && isascii(name[0]) && ! isalpha(name[0]) && name[1] == ':') { *cp = '/'; continue; } --- 1966,1973 ---- /* ** DOS drive specifier? */ ! if (isalpha((unsigned char)name[0]) ! && name[1] == ':' && !name[2]) { *cp = '/'; continue; }

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United States Naval Observatory time zone data available via browsers
by ado Oct. 28, 1995

Oct. 28, 1995

The URL is http://tycho.usno.navy.mil/tzones.html --ado

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tzcode95f.tar.gz and tzdata95j.tar.gz
by ado Oct. 28, 1995

Oct. 28, 1995

These new files... -rw-r--r-- 1 ado 65981 Oct 28 16:57 tzcode95f.tar.gz -rw-r--r-- 1 ado 69781 Oct 28 16:57 tzdata95j.tar.gz ...are available by anonymous ftp from elsie.nci.nih.gov (165.112.73.1) in the ~ftp/pub directory. The files incorporate European cleanups circulated earlier on the time zone mailing list; they also provide support for 64-bit time_t's and optimization in localtime.c --ado

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Re: old time zones (europe)
by Dik.Winter＠cwi.nl Oct. 25, 1995

Oct. 25, 1995

> There are some inconsistencies in the file: Indeed, but others than you are seeing. > Also, according to the Germany entry and to my vague memory, Germany > introduced DST in 1980 rather than 1981, which put pressure on all the > small ES countries to come to some kind of harmonisation. The file correctly notes that Germany introduced it in 1980 and Switzerland, Austria and Liechtenstein in 1981 (at least in version 95i). However there is a inconsistency in one of the lines for Luxembourg. It states: 1:00 Belgium MET%s 1979 while a similar line for Brussels states 1977. Should be changed in Luxembourg (the BeNeLux switched to "EC" rules in 1977). Further with respect to France. The file states that Shanks has no data on summertime in France in 1975 but that there is a note that states that summertime has been used. I just checked the Dutch railway timetable for summer 1975 and it says nothing about summer- time in France, so I presume no summertime. (In a later year, when it was unsure whether Germany would already switch to summer time until a very late stage the Dutch railway timetable came with double tables when Germany was involved. One for when summertime would be introduced and one when it would not be introduced.) The timetables are pretty good to establish in what years summertime was used; not for the exact starting and ending dates. dik -- dik t. winter, cwi, kruislaan 413, 1098 sj amsterdam, nederland, +31205924098 home: bovenover 215, 1025 jn amsterdam, nederland; e-mail: dik(a)cwi.nl

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Re: old time zones (europe)
by bs＠cs.uni-sb.de Oct. 25, 1995

Oct. 25, 1995

Rolf-Martin Mantel writes: [...] > Also, according to the Germany entry and to my vague memory, Germany > introduced DST in 1980 rather than 1981, which put pressure on all the > small ES countries to come to some kind of harmonisation. That's correct. I have here a paper from the PTB (Physikalisch-Technische Bundesanstalt, Braunschweig - the responsible "time authority" for Germany) which states: 1980: Apr. 6 to Sept. 28 (!!) 1981: Mar. 29 to Sept. 27 ... Bernard Sieloff U of Saarbruecken, Germany

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