# libc - Time Zone Functions

File: libc.info | Node: Time Zone Functions | Next: Time Functions Example | Prev: TZ Variable | Up: Calendar Time

### Functions and Variables for Time Zones

-- Variable: char *
  The array `tzname' contains two strings, which are the standard three-letter names of the pair of time zones (standard and daylight savings) that the user has selected. `tzname[0]' is the name of the standard time zone (for example, `"EST"'), and `tzname[1]' is the name for the time zone when daylight savings time is in use (for example, `"EDT"'). These correspond to the STD and DST strings (respectively) from the `TZ' environment variable.

  The `tzname' array is initialized from the `TZ' environment variable whenever `tzset', `ctime', `strftime', `mktime', or `localtime' is called.

--Function: void tzset (void)
  The `tzset' function initializes the `tzname' variable from the value of the `TZ' environment variable. It is not usually necessary for your program to call this function, because it is called automatically when you use the other time conversion functions that depend on the time zone.

The following variables are defined for compatibility with System V Unix. These variables are set by calling `localtime'.

-- Variable: long int timezone
  This contains the difference between GMT and local standard time, in seconds. For example, in the U.S. Eastern time zone, the value is `5*60*60'.
--Variable: int daylight
  This variable has a nonzero value if the standard U.S. daylight savings time rules apply.

Next: Time Functions Example | Up: Calendar Time

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