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

     The adjustment is made by speeding up (if that amount of time is posi-
     tive) or slowing down (if that amount of time is negative) the
     system's clock. If the amount of time is positive, the time moves
     twice as fast as before. If the amount of time is negative, the time
     moves half as fast as before. 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 superuser may adjust the time of day.

     The adjustment value will be rounded to the resolution of the system
     clock.

     adjtime() will fail if one or more of the following apply:

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

     EPERM    The process' effective user ID is not that of the superuser.

RESULT
     A 0 result indicates that the call succeeded. A -1 result indicates an
     error occurred, and in this case an error code is stored into the glo-
     bal variable errno.




Page 1                       Reliant UNIX 5.44                Printed 11/98

adjtime(2)                                                       adjtime(2)

SEE ALSO
     date(1), gettimeofday(3C).




















































Page 2                       Reliant UNIX 5.44                Printed 11/98