Export (0) Print
Expand All
This topic has not yet been rated - Rate this topic

_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 are declared in Time.h as follows.

extern int _daylight; 
extern int _dstbias; 
extern long _timezone; 
extern char *_tzname[2];

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 do not 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).

Did you find this helpful?
(1500 characters remaining)
Thank you for your feedback
Show:
© 2014 Microsoft. All rights reserved.