Node:Time Zone Functions, Next:Time Functions Example, Previous:TZ Variable, Up:Calendar Time
char * tzname [2] | Variable |
The array tzname contains two strings, which are the standard
names of the pair of time zones (standard and Daylight
Saving) 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 Saving Time is in use (for
example, "EDT" ). These correspond to the std and dst
strings (respectively) from the TZ environment variable. If
Daylight Saving Time is never used, tzname[1] is the empty string.
The The Though the strings are declared as |
void tzset (void) | Function |
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.
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The following variables are defined for compatibility with System V
Unix. Like tzname
, these variables are set by calling
tzset
or the other time conversion functions.
long int timezone | Variable |
This contains the difference between UTC and the latest local standard
time, in seconds west of UTC. For example, in the U.S. Eastern time
zone, the value is 5*60*60 . Unlike the tm_gmtoff member
of the broken-down time structure, this value is not adjusted for
daylight saving, and its sign is reversed. In GNU programs it is better
to use tm_gmtoff , since it contains the correct offset even when
it is not the latest one.
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int daylight | Variable |
This variable has a nonzero value if Daylight Saving Time rules apply. A nonzero value does not necessarily mean that Daylight Saving Time is now in effect; it means only that Daylight Saving Time is sometimes in effect. |