NAME
tzset — set time
zone conversion information
SYNOPSIS
#include <time.h> void tzset (void); extern char *tzname[]; extern long int timezone; extern int daylight;
DESCRIPTION
The tzset() function uses the value of the environment variable TZ to set time conversion information used by localtime(3) , ctime(3) , strftime(3) and mktime(3) . If TZ is absent from the environment, implementation-dependent default time zone information is used.
The tzset() function sets the
external variable
tzname as follows:
tzname[0] = "std"; tzname[1] =
"dst"; where
std and
dst are as
described in the
XBD
specification, envvar(7).
The tzset() function also sets the external variable daylight to 0 if Daylight Savings Time conversions should never be applied for the time zone in use; otherwise non-zero. The external variable timezone is set to the difference, in seconds, between Coordinated Universal Time (UTC) and local standard time, for example:
| TZ | timezone |
| EST | 5*60*60 |
| GMT | 0*60*60 |
| JST | -9*60*60 |
| MET | -1*60*60 |
| MST | 7*60*60 |
| PST | 8*60*60 |
RETURN VALUE
The tzset() function returns no value.
ERRORS
No errors are defined.
EXAMPLES
None.
APPLICATION USAGE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
ctime(3) , localtime(3) , mktime(3) , strftime(3) , <time.h> .
DERIVATION
Derived from Issue 1 of the SVID.