NAME

daylight, timezone, tzname, tzset - set timezone conversion information

SYNOPSIS

#include <time.h>



[XSI] extern int daylight;
extern long timezone;


[CX] extern char *tzname[2];
void tzset(void);

DESCRIPTION

The tzset() function shall use the value of the environment variable TZ to set time conversion information used by ctime, localtime, mktime, and strftime. If TZ is absent from the environment, implementation-defined default timezone information shall be used.

The tzset() function shall set the external variable tzname as follows:

tzname[0] = "std";
tzname[1] = "dst";

where std and dst are as described in XBD Environment Variables.

^[XSI] The tzset() function also shall set the external variable daylight to 0 if Daylight Savings Time conversions should never be applied for the timezone in use; otherwise, non-zero. The external variable timezone shall be set to the difference, in seconds, between Coordinated Universal Time (UTC) and local standard time.

RETURN VALUE

The tzset() function shall not return a value.

ERRORS

No errors are defined.

EXAMPLES

Example TZ variables and their timezone differences are given in the table below:

TZ	timezone
EST5EDT	5*60*60
GMT0	0*60*60
JST-9	-9*60*60
MET-1MEST	-1*60*60
MST7MDT	7*60*60
PST8PDT	8*60*60

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

ctime, localtime, mktime, strftime

XBD Environment Variables, <time.h>

CHANGE HISTORY

First released in Issue 1. Derived from Issue 1 of the SVID.

Issue 6

The example is corrected.