gettimeofday(2)                                   gettimeofday(2)



     NAME
          gettimeofday, settimeofday - get/set date and time

     SYNOPSIS
          #include <sys/time.h>

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

          int 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 depen-
          dent, 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 referenced 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 ap-
          plies locally only when Daylight Savings Time is in effect.

          Only the superuser may set the time of day or time zone.
          Changes to the time zone structure are effective for the
          current process only.

     RETURN VALUE
          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.




     April, 1990                                                     1

     gettimeofday(2)                                   gettimeofday(2)



     ERRORS
          The calls fail if:

          [EFAULT]       An argument address referenced invalid
                         memory.

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

     SEE ALSO
          date(1), adjtime(2), time(2), stime(2), ctime(3).












































     2                                                     April, 1990