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- /* Layout and location of TZif files. */
- #ifndef TZFILE_H
- #define TZFILE_H
- /*
- ** This file is in the public domain, so clarified as of
- ** 1996-06-05 by Arthur David Olson.
- */
- /*
- ** This header is for use ONLY with the time conversion code.
- ** There is no guarantee that it will remain unchanged,
- ** or that it will remain at all.
- ** Do NOT copy it to any system include directory.
- ** Thank you!
- */
- /*
- ** Information about time zone files.
- */
- #ifndef TZDIR
- #define TZDIR "/usr/share/zoneinfo" /* Time zone object file directory */
- #endif /* !defined TZDIR */
- #ifndef TZDEFAULT
- #define TZDEFAULT "/etc/localtime"
- #endif /* !defined TZDEFAULT */
- #ifndef TZDEFRULES
- #define TZDEFRULES "posixrules"
- #endif /* !defined TZDEFRULES */
- /* See Internet RFC 8536 for more details about the following format. */
- /*
- ** Each file begins with. . .
- */
- #define TZ_MAGIC "TZif"
- struct tzhead {
- char tzh_magic[4]; /* TZ_MAGIC */
- char tzh_version[1]; /* '\0' or '2' or '3' as of 2013 */
- char tzh_reserved[15]; /* reserved; must be zero */
- char tzh_ttisutcnt[4]; /* coded number of trans. time flags */
- char tzh_ttisstdcnt[4]; /* coded number of trans. time flags */
- char tzh_leapcnt[4]; /* coded number of leap seconds */
- char tzh_timecnt[4]; /* coded number of transition times */
- char tzh_typecnt[4]; /* coded number of local time types */
- char tzh_charcnt[4]; /* coded number of abbr. chars */
- };
- /*
- ** . . .followed by. . .
- **
- ** tzh_timecnt (char [4])s coded transition times a la time(2)
- ** tzh_timecnt (unsigned char)s types of local time starting at above
- ** tzh_typecnt repetitions of
- ** one (char [4]) coded UT offset in seconds
- ** one (unsigned char) used to set tm_isdst
- ** one (unsigned char) that's an abbreviation list index
- ** tzh_charcnt (char)s '\0'-terminated zone abbreviations
- ** tzh_leapcnt repetitions of
- ** one (char [4]) coded leap second transition times
- ** one (char [4]) total correction after above
- ** tzh_ttisstdcnt (char)s indexed by type; if 1, transition
- ** time is standard time, if 0,
- ** transition time is local (wall clock)
- ** time; if absent, transition times are
- ** assumed to be local time
- ** tzh_ttisutcnt (char)s indexed by type; if 1, transition
- ** time is UT, if 0, transition time is
- ** local time; if absent, transition
- ** times are assumed to be local time.
- ** When this is 1, the corresponding
- ** std/wall indicator must also be 1.
- */
- /*
- ** If tzh_version is '2' or greater, the above is followed by a second instance
- ** of tzhead and a second instance of the data in which each coded transition
- ** time uses 8 rather than 4 chars,
- ** then a POSIX-TZ-environment-variable-style string for use in handling
- ** instants after the last transition time stored in the file
- ** (with nothing between the newlines if there is no POSIX representation for
- ** such instants).
- **
- ** If tz_version is '3' or greater, the above is extended as follows.
- ** First, the POSIX TZ string's hour offset may range from -167
- ** through 167 as compared to the POSIX-required 0 through 24.
- ** Second, its DST start time may be January 1 at 00:00 and its stop
- ** time December 31 at 24:00 plus the difference between DST and
- ** standard time, indicating DST all year.
- */
- /*
- ** In the current implementation, "tzset()" refuses to deal with files that
- ** exceed any of the limits below.
- */
- #ifndef TZ_MAX_TIMES
- #define TZ_MAX_TIMES 2000
- #endif /* !defined TZ_MAX_TIMES */
- #ifndef TZ_MAX_TYPES
- /* This must be at least 17 for Europe/Samara and Europe/Vilnius. */
- #define TZ_MAX_TYPES 256 /* Limited by what (unsigned char)'s can hold */
- #endif /* !defined TZ_MAX_TYPES */
- #ifndef TZ_MAX_CHARS
- #define TZ_MAX_CHARS 50 /* Maximum number of abbreviation characters */
- /* (limited by what unsigned chars can hold) */
- #endif /* !defined TZ_MAX_CHARS */
- #ifndef TZ_MAX_LEAPS
- #define TZ_MAX_LEAPS 50 /* Maximum number of leap second corrections */
- #endif /* !defined TZ_MAX_LEAPS */
- #endif /* !defined TZFILE_H */
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