adjtime(2)                          CLIX                          adjtime(2)



  NAME

    adjtime - Corrects the time to allow synchronization of the system clock

  LIBRARY

    Berkeley Software Distribution Library (libbsd.a)

  SYNOPSIS

    #include <sys/time.h>

    int adjtime(
      struct timeval *delta ,
      struct timeval *olddelta );

  PARAMETERS

    delta      Points to a timeval structure that contains the time
               adjustment.  If delta is negative, the clock is slowed down by
               incrementing it more slowly than normal until the correction is
               complete.  If delta is positive, a larger increment than normal
               is used.

    olddelta   If olddelta is nonzero, the structure pointed to will contain,
               upon return, the number of microseconds still to be corrected
               from a previous call to adjtime().

  DESCRIPTION

    The adjtime() function makes small adjustments to the system time, as
    returned by the gettimeofday() function.  The skew used to perform the
    correction is generally 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.

    This call may be used by time servers that synchronize the clocks of
    computers in a local area network (LAN).  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.

  EXAMPLES

    To gradually slow down the system clock by five seconds:

    struct timeval adjust_tv;
    adjust_tv.tv_sec = 5;
    adjust_tv.tv_usec = 0;
    adjtime(&adjust_tv, (struct adjtime *)0);




  2/94 - Intergraph Corporation                                              1

  adjtime(2)                          CLIX                          adjtime(2)



  NOTES

    The adjtime() function may be executed only by the superuser.

  RETURN VALUES

    Upon successful completion, a value of 0 is returned.  Otherwise, a value
    of -1 is returned and errno is set to indicate the error.

  ERRORS

    The adjtime() function fails if any of the following are true:

    [EFAULT]   An argument points outside the process's allocated address
               space.

    [EPERM]    The effective user ID of the calling process is not superuser.

  RELATED INFORMATION

    Commands: ntp(1), ntpd(1), ntpdc(1)

    Functions:  gettimeofday(2)































  2                                              Intergraph Corporation - 2/94