

TIMEZONE              Environmental Variable             TIMEZONE




Time zone information

TTIIMMEEZZOONNEE=_s_t_a_n_d_a_r_d:_o_f_f_s_e_t[:_d_a_y_l_i_g_h_t: _d_a_t_e:_d_a_t_e:_h_o_u_r:_m_i_n_u_t_e_s]

TIMEZONE  is an  environmental parameter  that  holds information
about  the  user's  time  zone.   This  information  is  used  by
COHERENT's time  routines to  construct their description  of the
current time and day.

To set the TIMEZONE parameter, use the sseett command, as follows:


        set TIMEZONE=[description]


where [description] is  the string that describes your time zone.
What this string consists of will be described below.  Most users
write this  command into the  file .pprrooffiillee, so  that TIMEZONE is
set automatically whenever they log onto the COHERENT system.

***** The Description String *****

A TTIIMMEEZZOONNEE  description string consists of  seven fields that are
separated by  colons.  Fields  1 and 2  must be filled;  fields 3
through 7 are optional.

Field 1 gives the name of your standard time zone.  Field 2 gives
the  time zone's  offset  from Greenwich  Mean  Time in  minutes.
Offsets are  positive for time zones west  of Greenwich and nega-
tive for  time zones  east of  Greenwich.  For example,  users in
Chicago set these fields as follows:


        TIMEZONE=CST:360


CCSSTT  is an  abbreviation for Central  Standard Time,  that area's
time zone; and 360 refers to the fact that Chicago's time zone is
360 minutes (six hours) behind that of Greenwich.

Field 3  gives the name  of the local daylight  saving time zone.
In Chicago, for example, this field would be set as follows:


        TIMEZONE=CST:360:CDT


CDT is an abbreviation for Central Daylight Time.  The absence of
this field indicates that  your area does not use daylight saving
time.

Fields 4  and 5 specify  the dates on which  daylight saving time
begins and ends.   If field 3 is set but  fields 4 and 5 are not,
changes between  standard time and  daylight saving time  are as-


COHERENT Lexicon                                           Page 1




TIMEZONE              Environmental Variable             TIMEZONE



sumed to occur at the times legislated in the United States: at 2
A.M. standard  time on the first  Sunday in April, and  at 2 A.M.
daylight saving time on the last Sunday in October.

Fields  4  and  5 each  consist  of  three  numbers separated  by
periods.  The first  number specifies which occurrence of the day
in the month marks the change, counting positive occurrences from
the beginning of the  month and negative occurrences from the the
end of the month.  The second number specifies a day of the week,
numbering Sunday  as one.  The third number  specifies a month of
the  year, numbering  January as  one.   For example,  in Chicago
fields 4 and 5 are set to the following:


        TIMEZONE=CST:360:CDT:1.1.4:-1.1.10


If the first number in either field is set to zero, then the last
two numbers  are assumed to  indicate an absolute  date.  This is
done because some countries switch to daylight saving time on the
same day each year, instead of a given day of the week.

Finally, fields  6 and  7 specify  the hour of  the day  at which
daylight saving  time begins and ends, and  the number of minutes
of adjustment.  In Chicago, these are set as follows:


        TIMEZONE=CST:360:CDT:1.1.4:-1.1.10:2:60


The `2' of field 6  indicates that the switch to daylight savings
time  occurs at  2 A.M.   The  ``60'' of  field 7  indicates that
daylight  savings time  changes  the local  time  by 60  minutes.
Although 60  minutes is the standard change,  some regions of the
world shift by 30, 45, 90, or 120 minutes; the last shift is also
called ``double daylight saving time''.

For an example of this variable's use in a program, see the entry
for asctime.

***** See Also *****

environmental variables, setenv, time (overview)

For  those  requiring  more  information  on this  subject,  much
research has been  performed by astrologers.  See _T_i_m_e _C_h_a_n_g_e_s _i_n
_t_h_e  _W_o_r_l_d,  compiled   by  Doris  Chase  Doane  (three  volumes,
Hollywood, California, Professional Astrologers, Inc., 1970).









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