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Annotation of 43BSDReno/share/zoneinfo/tzfile.5, revision 1.1

1.1     ! root        1: .TH TZFILE 5
        !             2: .SH NAME
        !             3: tzfile \- time zone information
        !             4: .SH SYNOPSIS
        !             5: .B
        !             6: #include <tzfile.h>
        !             7: .SH DESCRIPTION
        !             8: The time zone information files used by
        !             9: .IR tzset (3)
        !            10: begin with bytes reserved for future use,
        !            11: followed by four four-byte values of type
        !            12: .BR long ,
        !            13: written in a ``standard'' byte order
        !            14: (the high-order byte of the value is written first).
        !            15: These values are,
        !            16: in order:
        !            17: .TP
        !            18: .I tzh_ttisstdcnt
        !            19: The number of standard/wall indicators stored in the file.
        !            20: .TP
        !            21: .I tzh_leapcnt
        !            22: The number of leap seconds for which data is stored in the file.
        !            23: .TP
        !            24: .I tzh_timecnt
        !            25: The number of "transition times" for which data is stored
        !            26: in the file.
        !            27: .TP
        !            28: .I tzh_typecnt
        !            29: The number of "local time types" for which data is stored
        !            30: in the file (must not be zero).
        !            31: .TP
        !            32: .I tzh_charcnt
        !            33: The number of characters of "time zone abbreviation strings"
        !            34: stored in the file.
        !            35: .PP
        !            36: The above header is followed by
        !            37: .I tzh_timecnt
        !            38: four-byte values of type
        !            39: .BR long ,
        !            40: sorted in ascending order.
        !            41: These values are written in ``standard'' byte order.
        !            42: Each is used as a transition time (as returned by
        !            43: .IR time (2))
        !            44: at which the rules for computing local time change.
        !            45: Next come
        !            46: .I tzh_timecnt
        !            47: one-byte values of type
        !            48: .BR "unsigned char" ;
        !            49: each one tells which of the different types of ``local time'' types
        !            50: described in the file is associated with the same-indexed transition time.
        !            51: These values serve as indices into an array of
        !            52: .I ttinfo
        !            53: structures that appears next in the file; 
        !            54: these structures are defined as follows:
        !            55: .in +.5i
        !            56: .sp
        !            57: .nf
        !            58: .ta .5i +\w'unsigned int\0\0'u
        !            59: struct ttinfo {        
        !            60:        long    tt_gmtoff;
        !            61:        int     tt_isdst;
        !            62:        unsigned int    tt_abbrind;
        !            63: };
        !            64: .in -.5i
        !            65: .fi
        !            66: .sp
        !            67: Each structure is written as a four-byte value for
        !            68: .I tt_gmtoff
        !            69: of type
        !            70: .BR long ,
        !            71: in a standard byte order, followed by a one-byte value for
        !            72: .I tt_isdst
        !            73: and a one-byte value for
        !            74: .IR tt_abbrind .
        !            75: In each structure,
        !            76: .I tt_gmtoff
        !            77: gives the number of seconds to be added to GMT,
        !            78: .I tt_isdst
        !            79: tells whether
        !            80: .I tm_isdst
        !            81: should be set by
        !            82: .I localtime (3)
        !            83: and
        !            84: .I tt_abbrind
        !            85: serves as an index into the array of time zone abbreviation characters
        !            86: that follow the
        !            87: .I ttinfo
        !            88: structure(s) in the file.
        !            89: .PP
        !            90: Then there are
        !            91: .I tzh_leapcnt
        !            92: pairs of four-byte values, written in standard byte order;
        !            93: the first value of each pair gives the time
        !            94: (as returned by 
        !            95: .IR time(2))
        !            96: at which a leap second occurs;
        !            97: the second gives the
        !            98: .I total
        !            99: number of leap seconds to be applied after the given time.
        !           100: The pairs of values are sorted in ascending order by time.
        !           101: .PP
        !           102: Finally there are
        !           103: .I tzh_ttisstdcnt
        !           104: standard/wall indicators, each stored as a one-byte value;
        !           105: they tell whether the transition times associated with local time types
        !           106: were specified as standard time or wall clock time,
        !           107: and are used when a time zone file is used in handling POSIX-style
        !           108: time zone environment variables.
        !           109: .PP
        !           110: .I Localtime
        !           111: uses the first standard-time
        !           112: .I ttinfo
        !           113: structure in the file
        !           114: (or simply the first
        !           115: .I ttinfo
        !           116: structure in the absence of a standard-time structure)
        !           117: if either
        !           118: .I tzh_timecnt
        !           119: is zero or the time argument is less than the first transition time recorded
        !           120: in the file.
        !           121: .SH SEE ALSO
        !           122: ctime(3)
        !           123: .. @(#)tzfile.5        4.2

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