GETTIMEOFDAY(2)     UNIX Programmer's Manual	  GETTIMEOFDAY(2)


NAME
     gettimeofday, settimeofday - get/set date and time

SYNOPSIS
     #include <sys/time.h>

     gettimeofday(tp, tzp)
     struct timeval *tp;
     struct timezone *tzp;

     settimeofday(tp, tzp)
     struct timeval *tp;
     struct timezone *tzp;

DESCRIPTION
     The system's notion of the current Greenwich time and the
     current time zone is obtained with the gettimeofday call,
     and set with the settimeofday call.  The time is expressed
     in seconds and microseconds since midnight (0 hour), January
     1, 1970.  The resolution of the system clock is hardware
     dependent, and the time may be updated continuously or in
     ``ticks.'' If tzp is zero, the time zone information will
     not be returned or set.

     The structures pointed to by tp and tzp are defined in
     <sys/time.h> as:

	  struct timeval {
	       long tv_sec;	   /* seconds since Jan. 1, 1970 */
	       long tv_usec;	   /* and microseconds */
	  };

	  struct timezone {
	       int  tz_minuteswest;	/* of Greenwich */
	       int  tz_dsttime;    /* type of dst correction to apply */
	  };

     The timezone structure indicates the local time zone (meas-
     ured in minutes of time westward from Greenwich), and a flag
     that, if nonzero, indicates that Daylight Saving time
     applies locally during the appropriate part of the year.

     Only the super-user may set the time of day or time zone.

RETURN
     A 0 return value indicates that the call succeeded.  A -1
     return value indicates an error occurred, and in this case
     an error code is stored into the global variable errno.

ERRORS
     The following error codes may be set in errno:


Printed 11/26/99	  May 14, 1986				1


GETTIMEOFDAY(2)     UNIX Programmer's Manual	  GETTIMEOFDAY(2)


     [EFAULT]	    An argument address referenced invalid
		    memory.

     [EPERM]	    A user other than the super-user attempted to
		    set the time.

SEE ALSO
     date(1), adjtime(2), ctime(3), timed(8)


Printed 11/26/99	  May 14, 1986				2


 
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