ADJTIME(2-SVR4)     RISC/os Reference Manual      ADJTIME(2-SVR4)



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(3C), advancing or retarding it by
     the amount of time specified in the struct timeval pointed
     to by delta.

     The adjustment is effected by speeding up (if that amount of
     time is positive) or slowing down (if that amount of time is
     negative) the system's clock by some small percentage, gen-
     erally a fraction of one percent.  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 0, then olddelta returns the
     status of the effects of the previous adjtime call and there
     is no effect on the time correction as a result of this
     call.  If olddelta is not a NULL pointer, then the structure
     it points to will contain, upon return, the number of
     seconds and/or microseconds still to be corrected from the
     earlier call.  If olddelta is a NULL pointer, the
     corresponding information will not be returned.

     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.

     Only the super-user may adjust the time of day.

     The adjustment value will be silently rounded to the resolu-
     tion of the system clock.

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              delta or olddelta points outside the
                         process's allocated address space, or
                         olddelta points to a region of the



                        Printed 11/19/92                   Page 1

ADJTIME(2-SVR4)     RISC/os Reference Manual      ADJTIME(2-SVR4)



                         process' allocated address space that is
                         not writable.

     EPERM               The process's effective user ID is not
                         that of the super-user.

SEE ALSO
     gettimeofday(3C)
     date(1) in the User's Reference Manual.














































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