*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->OpenBSD man pages -> tzfile (5)              
Title
Content
Arch
Section
 

TZFILE(5)

Contents


NAME    [Toc]    [Back]

     tzfile - time zone information

SYNOPSIS    [Toc]    [Back]

     #include <tzfile.h>

DESCRIPTION    [Toc]    [Back]

     The time zone information files used by tzset(3) begin  with
the magic
     characters "TZif" to identify themselves as time zone information files,
     followed by sixteen bytes reserved for future use,  followed
by six fourbyte
  values of type long written in a ``standard'' byte order (the
     high-order byte of the value is written first).  These  values are, in order:


     tzh_ttisgmtcnt  The number of UTC/local indicators stored in
the file.

     tzh_ttisstdcnt   The  number  of  standard/wall   indicators
stored in the
                     file.

     tzh_leapcnt     The number of leap seconds for which data is
stored in
                     the file.

     tzh_timecnt     The number of "transition times"  for  which
data is stored
                     in the file.

     tzh_typecnt      The  number of "local time types" for which
data is stored
                     in the file (must not be zero).

     tzh_charcnt     The number of characters of "time  zone  abbreviation
                     strings" stored in the file.

     The above header is followed by tzh_timecnt four-byte values
of type
     long, sorted in ascending order.  These values  are  written
in
     ``standard''  byte order.  Each is used as a transition time
(as returned
     by time(3)) at which the  rules  for  computing  local  time
change.  Next
     come tzh_timecnt one-byte values of type unsigned char; each
one tells
     which of the different types of  ``local  time''  types  described in the
     file  is  associated  with the same-indexed transition time.
These values
     serve as indices into an array of ttinfo structures that appears next in
     the file; these structures are defined as follows:

           struct ttinfo {
                long          tt_gmtoff;
                int           tt_isdst;
                unsigned int  tt_abbrind;
           };

     Each structure is written as a four-byte value for tt_gmtoff
of type
     long, in a standard byte order, followed by a one-byte value
for tt_isdst
     and  a  one-byte  value  for tt_abbrind.  In each structure,
tt_gmtoff gives
     the number of seconds to be added  to  UTC,  tt_isdst  tells
whether tm_isdst
     should  be  set  by localtime(3) and tt_abbrind serves as an
index into the
     array of time zone abbreviation characters that  follow  the
ttinfo structure(s)
 in the file.

     Then  there are tzh_leapcnt pairs of four-byte values, written in standard
     byte order; the first value of each pair gives the time  (as
returned by
     time(3)) at which a leap second occurs; the second gives the
total number
     of leap seconds to be applied after  the  given  time.   The
pairs of values
     are sorted in ascending order by time.

     Then there are tzh_ttisstdcnt standard/wall indicators, each
stored as a
     one-byte value; they tell whether the transition times associated with
     local  time  types  were  specified as standard time or wall
clock time, and
     are used when a time zone file is used  in  handling  POSIXstyle time zone
     environment variables.

     Finally  there are tzh_ttisgmtcnt UTC/local indicators, each
stored as a
     one-byte value; they tell whether the transition times associated with
     local  time  types  were specified as UTC or local time, and
are used when a
     time zone file is used in handling POSIX-style time zone environment
     variables.

     localtime(3)  uses  the first standard-time ttinfo structure
in the file,
     or simply the first ttinfo structure in  the  absence  of  a
standard-time
     structure,  if  either tzh_timecnt is zero or the time argument is less
     than the first transition time recorded in the file.

SEE ALSO    [Toc]    [Back]

      
      
     ctime(3)

OpenBSD      3.6                           May      24,      1999
[ Back ]
 Similar pages
Name OS Title
settz Tru64 Set system time zone information.
tzname Tru64 sets and accesses time zone conversion information
tzset Tru64 sets and accesses time zone conversion information
timezone Tru64 sets and accesses time zone conversion information
daylight Tru64 sets and accesses time zone conversion information
adjkerntz FreeBSD adjust local time CMOS clock to reflect time zone changes and keep current timezone offset for the k...
zic Tru64 Time zone compiler
zdump Linux time zone dumper
zic OpenBSD time zone compiler
zdump OpenBSD time zone dumper
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service