gettimeofday(3C)                 UNIX System V                 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.

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

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

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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