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(), ctime(), strftime() and mktime(). 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, Environment Variables .

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(), localtime(), mktime(), strftime(), <time.h>.

DERIVATION

Derived from Issue 1 of the SVID.