tzfile \- time zone information
The time zone information files used by
begin with bytes reserved for future use,
followed by four four-byte values of type
written in a ``standard'' byte order
(the high-order byte of the value is written first).
The number of standard/wall indicators stored in the file.
The number of leap seconds for which data is stored in the file.
The number of "transition times" for which data is stored
The number of "local time types" for which data is stored
in the file (must not be zero).
The number of characters of "time zone abbreviation strings"
The above header is followed by
sorted in ascending order.
These values are written in ``standard'' byte order.
Each is used as a transition time (as returned by
at which the rules for computing local time change.
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
structures that appears next in the file;
these structures are defined as follows:
.ta .5i +\w'unsigned int\0\0'u
Each structure is written as a four-byte value for
in a standard byte order, followed by a one-byte value for
gives the number of seconds to be added to GMT,
serves as an index into the array of time zone abbreviation characters
structure(s) in the file.
pairs of four-byte values, written in standard byte order;
the first value of each pair gives the time
at which a leap second occurs;
number of leap seconds to be applied after the given time.
The pairs of values are sorted in ascending order by time.
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 POSIX-style
time zone environment variables.
uses the first standard-time
structure in the absence of a standard-time structure)
is zero or the time argument is less than the first transition time recorded