Unix/Linux Go Back    


OpenDarwin 7.2.1 - man page for adjtime (opendarwin section 2)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


ADJTIME(2)			     BSD System Calls Manual			       ADJTIME(2)

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

SYNOPSIS
     #include <sys/time.h>

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

DESCRIPTION
     Adjtime() makes small adjustments to the system time, as returned by gettimeofday(2),
     advancing or retarding it by the time specified by the timeval delta.  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.  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.  If olddelta is non-nil, the structure
     pointed to will contain, upon return, the number of microseconds still to be corrected from
     the earlier call.

     This call may be used by 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 call adjtime() is restricted to the super-user.

RETURN VALUES
     A return value of 0 indicates that the call succeeded.  A return value of -1 indicates that
     an error occurred, and in this case an error code is stored in the global variable errno.

ERRORS
     Adjtime() will fail if:

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

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

SEE ALSO
     date(1), gettimeofday(2), timed(8), timedc(8),

     R. Gusella and S. Zatti, TSP: The Time Synchronization Protocol for UNIX 4.3BSD.

HISTORY
     The adjtime() function call appeared in 4.3BSD.

4.3 Berkeley Distribution		   June 4, 1993 		4.3 Berkeley Distribution
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 09:11 AM.