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Member "tzfile.h" (12 Jul 2022, 4000 Bytes) of package /linux/misc/tzcode2022g.tar.gz:

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    1 /* Layout and location of TZif files.  */
    2 
    3 #ifndef TZFILE_H
    4 
    5 #define TZFILE_H
    6 
    7 /*
    8 ** This file is in the public domain, so clarified as of
    9 ** 1996-06-05 by Arthur David Olson.
   10 */
   11 
   12 /*
   13 ** This header is for use ONLY with the time conversion code.
   14 ** There is no guarantee that it will remain unchanged,
   15 ** or that it will remain at all.
   16 ** Do NOT copy it to any system include directory.
   17 ** Thank you!
   18 */
   19 
   20 /*
   21 ** Information about time zone files.
   22 */
   23 
   24 #ifndef TZDIR
   25 # define TZDIR "/usr/share/zoneinfo" /* Time zone object file directory */
   26 #endif /* !defined TZDIR */
   27 
   28 #ifndef TZDEFAULT
   29 # define TZDEFAULT "/etc/localtime"
   30 #endif /* !defined TZDEFAULT */
   31 
   32 #ifndef TZDEFRULES
   33 # define TZDEFRULES "posixrules"
   34 #endif /* !defined TZDEFRULES */
   35 
   36 
   37 /* See Internet RFC 8536 for more details about the following format.  */
   38 
   39 /*
   40 ** Each file begins with. . .
   41 */
   42 
   43 #define TZ_MAGIC    "TZif"
   44 
   45 struct tzhead {
   46     char    tzh_magic[4];       /* TZ_MAGIC */
   47     char    tzh_version[1];     /* '\0' or '2'-'4' as of 2021 */
   48     char    tzh_reserved[15];   /* reserved; must be zero */
   49     char    tzh_ttisutcnt[4];   /* coded number of trans. time flags */
   50     char    tzh_ttisstdcnt[4];  /* coded number of trans. time flags */
   51     char    tzh_leapcnt[4];     /* coded number of leap seconds */
   52     char    tzh_timecnt[4];     /* coded number of transition times */
   53     char    tzh_typecnt[4];     /* coded number of local time types */
   54     char    tzh_charcnt[4];     /* coded number of abbr. chars */
   55 };
   56 
   57 /*
   58 ** . . .followed by. . .
   59 **
   60 **  tzh_timecnt (char [4])s     coded transition times a la time(2)
   61 **  tzh_timecnt (unsigned char)s    types of local time starting at above
   62 **  tzh_typecnt repetitions of
   63 **      one (char [4])      coded UT offset in seconds
   64 **      one (unsigned char) used to set tm_isdst
   65 **      one (unsigned char) that's an abbreviation list index
   66 **  tzh_charcnt (char)s     '\0'-terminated zone abbreviations
   67 **  tzh_leapcnt repetitions of
   68 **      one (char [4])      coded leap second transition times
   69 **      one (char [4])      total correction after above
   70 **  tzh_ttisstdcnt (char)s      indexed by type; if 1, transition
   71 **                  time is standard time, if 0,
   72 **                  transition time is local (wall clock)
   73 **                  time; if absent, transition times are
   74 **                  assumed to be local time
   75 **  tzh_ttisutcnt (char)s       indexed by type; if 1, transition
   76 **                  time is UT, if 0, transition time is
   77 **                  local time; if absent, transition
   78 **                  times are assumed to be local time.
   79 **                  When this is 1, the corresponding
   80 **                  std/wall indicator must also be 1.
   81 */
   82 
   83 /*
   84 ** If tzh_version is '2' or greater, the above is followed by a second instance
   85 ** of tzhead and a second instance of the data in which each coded transition
   86 ** time uses 8 rather than 4 chars,
   87 ** then a POSIX-TZ-environment-variable-style string for use in handling
   88 ** instants after the last transition time stored in the file
   89 ** (with nothing between the newlines if there is no POSIX representation for
   90 ** such instants).
   91 **
   92 ** If tz_version is '3' or greater, the above is extended as follows.
   93 ** First, the POSIX TZ string's hour offset may range from -167
   94 ** through 167 as compared to the POSIX-required 0 through 24.
   95 ** Second, its DST start time may be January 1 at 00:00 and its stop
   96 ** time December 31 at 24:00 plus the difference between DST and
   97 ** standard time, indicating DST all year.
   98 */
   99 
  100 /*
  101 ** In the current implementation, "tzset()" refuses to deal with files that
  102 ** exceed any of the limits below.
  103 */
  104 
  105 #ifndef TZ_MAX_TIMES
  106 # define TZ_MAX_TIMES 2000
  107 #endif /* !defined TZ_MAX_TIMES */
  108 
  109 #ifndef TZ_MAX_TYPES
  110 /* This must be at least 17 for Europe/Samara and Europe/Vilnius.  */
  111 # define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
  112 #endif /* !defined TZ_MAX_TYPES */
  113 
  114 #ifndef TZ_MAX_CHARS
  115 # define TZ_MAX_CHARS 50    /* Maximum number of abbreviation characters */
  116                 /* (limited by what unsigned chars can hold) */
  117 #endif /* !defined TZ_MAX_CHARS */
  118 
  119 #ifndef TZ_MAX_LEAPS
  120 # define TZ_MAX_LEAPS 50    /* Maximum number of leap second corrections */
  121 #endif /* !defined TZ_MAX_LEAPS */
  122 
  123 #endif /* !defined TZFILE_H */