_daylight
, _dstbias
, _timezone
, and _tzname
_daylight
, _dstbias
, _timezone
, and _tzname
are used in some time and date routines to make local-time adjustments. These global variables have been deprecated for the more secure functional versions, which should be used in place of the global variables.
Global variable | Functional equivalent |
---|---|
_daylight |
_get_daylight |
_dstbias |
_get_dstbias |
_timezone |
_get_timezone |
_tzname |
_get_tzname |
They're declared in Time.h as follows.
Syntax
extern int _daylight;
extern int _dstbias;
extern long _timezone;
extern char *_tzname[2];
Remarks
On a call to _ftime
, localtime
, or _tzset
, the values of _daylight
, _dstbias
, _timezone
, and _tzname
are determined from the value of the TZ
environment variable. If you don't explicitly set the value of TZ
, _tzname[0]
and _tzname[1]
contain the default settings of "PST" and "PDT" respectively. The time-manipulation functions (_tzset
, _ftime
, and localtime
) attempt to set the values of _daylight
, _dstbias
and _timezone
by querying the operating system for the default value of each variable. The time-zone global variable values are shown in the following table.
Variable | Value |
---|---|
_daylight |
Nonzero if daylight saving time (DST) zone is specified in TZ or determined from the operating system; otherwise, 0. The default value is 1. |
_dstbias |
Offset for daylight saving time. |
_timezone |
Difference in seconds between coordinated universal time and local time. The default value is 28,800. |
_tzname[0] |
Time-zone name derived from the TZ environment variable. The default value is "PST". |
_tzname[1] |
DST zone name derived from the TZ environment variable. The default value is "PDT" (Pacific daylight time). |
See also
Global variables
_get_daylight
_get_dstbias
_get_timezone
_get_tzname
Σχόλια
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