System Calls                                           adjtime(2)



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

SYNOPSIS
     #include 

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


DESCRIPTION
     The adjtime() function 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. The time is always a mono-
     tonically 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 with 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 con-
     tain, upon successful 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 a processes with appropriate privileges can adjust  the
     time of day.


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

RETURN VALUES




SunOS 5.11          Last change: 20 Jan 2003                    1






System Calls                                           adjtime(2)



     Upon successful completion, adjtime() returns 0.  Otherwise,
     it returns -1 and sets errno to indicate the error.

ERORS
     The adjtime() function will fail if:

     EFAULT    The delta or olddelta argument 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.


     EINVAL    The tvusec member of delta is  not  within  valid
               range (-1000000 to 1000000).


     EPERM     The {PRIVSYSTIME} privilege is not  asserted  in
               the effective set of the calling process.



     Additionally, the adjtime() function will  fail  for  32-bit
     interfaces if:

     EOVERFLOW    The size of the tvsec member  of  the  timeval
                  structure  pointed  to by olddelta is too small
                  to contain the correct number of seconds.


SEE ALSO
     date(1), gettimeofday(3C), privileges(5)
























SunOS 5.11          Last change: 20 Jan 2003                    2