gettimeofday(3C)                                           gettimeofday(3C)


   NAME
         gettimeofday, settimeofday - get or set the date and time

   SYNOPSIS
         #include <sys/time.h>

         int gettimeofday (struct timeval *tp);

         int settimeofday (struct timeval *tp);

   DESCRIPTION
         gettimeofday gets and settimeofday sets the system's notion of the
         current time.  The current time is expressed in elapsed seconds and
         microseconds since 00:00 Universal Coordinated Time, January 1, 1970.
         The resolution of the system clock is hardware dependent; the time
         may be updated continuously, or in clock ticks.

         tp points to a timeval structure, which includes the following
         members:

               long    tvsec;    /* seconds since Jan. 1, 1970 */
               long    tvusec;   /* and microseconds */

         If tp is a NULL pointer, the current time information is not returned
         or set.

         The TZ environment variable holds time zone information.  See
         timezone(4).

         Only the privileged user may set the time of day.

   RETURN
         A -1 return value indicates an error occurred and errno has been set.

   ERRORS
         The following error codes may be set in errno:

         EINVAL              tp specifies an invalid time.

         EPERM               A user other than the privileged user attempted
                             to set the time or time zone.

   SEE ALSO
         adjtime(2), ctime(3C), timezone(4)

   NOTES
         The implementation of settimeofday ignores the tvusec field of tp.
         If the time needs to be set with better than one second accuracy,
         call settimeofday for the seconds and then adjtime for finer
         accuracy.



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