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BSD 2.11 - man page for gettimeofday (bsd section 2)

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GETTIMEOFDAY(2) 								  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 (measured 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:

       [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)

4th Berkeley Distribution		   May 14, 1986 			  GETTIMEOFDAY(2)
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