adjtime(2)                                                adjtime(2)


       NAME
             adjtime - correct the time to allow synchronization of the
             system clock

       SYNOPSIS
             #include <sys/time.h>
             int adjtime(struct timeval *delta, struct timeval *olddelta);

       DESCRIPTION
             adjtime adjusts the system's notion of the current time, as
             returned by gettimeofday(2), advancing or retarding it by the
             amount of time specified in the struct timeval pointed to by
             delta.

             This call may be used in time servers that synchronize the
             clocks of computers in a local area network.  Such time
             servers would slow down the clocks of some machines and speed
             up the clocks of others to bring them to the average network
             time.

             The adjustment is effected by speeding up (if the adjustment
             is positive) or slowing down (if the adjustment is negative)
             the system's clock by some small percentage, generally a
             fraction of one percent; the clock may be speeded up at a
             faster rate for a large positive adjustment.  Thus, the time
             is always a monotonically increasing function.

             A time correction from an earlier call to adjtime may not be
             finished when adjtime is called again.  If delta is NULL, then
             olddelta returns information on the previous adjtime call and
             there is no effect on the time correction as a result of this
             call.  If olddelta is not NULL, then the structure it points
             to contains, on return, the time still to be corrected from
             the earlier call.  If olddelta is NULL, the information is not
             returned.

             Only a process with the appropriate privilege (P_SYSOPS) can
             adjust the time of day.

             The adjustment value is silently rounded to the resolution of
             the system clock.

          Return Values
             On success, adjtime returns 0.  On failure, adjtime returns -1
             and sets errno to identify the error.



                           Copyright 1994 Novell, Inc.               Page 1

      adjtime(2)                                                adjtime(2)


         Errors
            In the following conditions, adjtime fails and sets errno to:

            EFAULT      delta or olddelta points outside the process's
                        allocated address space, or olddelta points to a
                        region of the process's allocated address space
                        that is not writable.

            EPERM       The calling process does not have the appropriate
                        privilege (P_SYSOPS) to change the time of day.

      REFERENCES
            date(1), gettimeofday(2), stime(2)



































                          Copyright 1994 Novell, Inc.               Page 2