# Setting the TZ Environment Variable

If running the 32-bit version of WinVN under Windows NT or Windows95, this information is obtained automatically from the date/time control panel. You do not need the TZ variable.

If running the 16-bit version of WinVN under Windows 3.x however, you must set the TZ environment variable. This variable should be set in DOS, before running Windows

Use the following syntax to set the TZ environment variable:

set TZ=tzn[+ | -]hh[:mm[:ss] ][dzn]

The tzn must be a three-letter time-zone name, such as PST, followed by an optionally signed number, + -hh, giving the difference in hours between Coordinated Universal Time (UTC). and local time. To specify the exact local time, the hours can be followed by minutes, :mm; seconds, :ss; and a three-letter daylight-saving-time zone, dzn, such as PDT. Separate hours, minutes, and seconds with colons. If daylight saving time is never in effect, as is the case in certain states and localities, set TZ without a value for dzn.

The TZ environment variable is depending from the C-Library used. WinVN [de] is compiled with WATCOM C/C++. The following extentions are available for WinVN [de]

The value of the TZ environment variable should be set as follows (spaces are for clarity only):

std offset dst offset , rule

The expanded format is as follows:

std offset[dst[offset][,start[/time],end[/time]]]

std, dst

three or more letters that are the designation for the standard (std) or summer (dst)

time zone. Only std is required. If dst is omitted, then summer time does not apply in

this locale. Upper- and lowercase letters are allowed. Any characters except for a

leading colon (:), digits, comma (,), minus (-), plus (+), and ASCII NUL (\0) are allowed.

offset

indicates the value one must add to the local time to arrive at Coordinated Universal

Time (UTC). The offset has the form:

hh[:mm[:ss]]

The minutes (mm) and seconds (ss) are optional. The hour (hh) is required and may be a single digit. The offset following std is required. If no offset follows dst, summer time is assumed to be one hour ahead of standard time. One or more digits may be used; the value is always interpreted as a decimal number. The hour may bebetween 0 and 24, and the minutes (and seconds) - if present - between 0 and 59. If preceded by a "-", the time zone will be east of the Prime Meridian ; otherwise it will be west (which may be indicated by an optional preceding "+").

rule

indicates when to change to and back from summer time. The rule has the form:

date/time,date/time

where the first date describes when the change from standard to summer time occurs and the second date describes when the change back happens. Each time field describes when, in current local time, the change to the other time is made.

The format of date may be one of the following:

Jn

The Julian day n (1 <= n <= 365). Leap days are not counted. That is, in all years - including leap years - February 28 is day 59 and March 1 is day 60. It is impossible to explicitly refer to the occasional February 29.

n

The zero-based Julian day (0 <= n <= 365). Leap years are counted, and it is possible to refer to February 29.

Mm.n.d

The d'th day (0 <= d <= 6) of week n of month m of the year (1 <= n <= 5, 1 <= m <= 12, where week 5 means "the last d day in month m" which may occur in the fourth or fifth week). Week 1 is the first week in which the d'th day occurs. Day zero is Sunday.

The time has the same format as offset except that no leading sign ("+" or "-") is allowed. The default, if time is omitted, is 02:00:00.

Some examples are:

TZ=EST5EDT

Eastern Standard Time is 5 hours earlier than Coordinated Universal Time (UTC). Standard time and daylight saving time both apply to this locale. By default, Eastern Daylight Time (EDT) is one hour ahead of standard time (i.e., EDT4). Since it is not specified, daylight saving time starts on the first Sunday of April at 2:00 A.M. and ends on the last Sunday of October at 2:00 A.M. This is the default when the TZ

- variable is not set.

TZ=EST5EDT4,M4.1.0/02:00:00,M10.5.0/02:00:00

This is the full specification for the default when the TZ variable is not set. Eastern Standard Time is 5 hours earlier than Coordinated Universal Time (UTC). Standard time and daylight saving time both apply to this locale. Eastern Daylight Time (EDT) is one hour ahead of standard time. Daylight saving time starts on the first (1) Sunday (0) of April (4) at 2:00 A.M. and ends on the last (5) Sunday (0) of October (10) at 2:00 A.M.

TZ=PST8PDT

Pacific Standard Time is 8 hours earlier than Coordinated Universal Time (UTC). Standard time and daylight saving time both apply to this locale. By default, Pacific Daylight Time is one hour ahead of standard time (i.e., PDT7). Since it is not specified, daylight saving time starts on the first Sunday of April at 2:00 A.M. and ends on the last Sunday of October at 2:00 A.M.

TZ=NST3:30NDT1:30

Newfoundland Standard Time is 3 and 1/2 hours earlier than Coordinated Universal Time (UTC). Standard time and daylight saving time both apply to this locale. Newfoundland Daylight Time is 1 and 1/2 hours earlier than Coordinated Universal Time (UTC).

TZ=CET-1CEST-2,M3.5.0,M10.5.0

This is useful in germany. Central European Time is one hour east of UTC. During daylight saving time ( named Central European Summer Time ) it is two hours east of UTC. Daylight saving time starts on the last Sunday of March at 02:00 A.M and ends on the last Sunday of October at 02:00 A.M.