*nix Documentation Project
·  Home
 +   man pages
·  Linux HOWTOs
·  FreeBSD Tips
·  *niX Forums

  man pages->FreeBSD man pages -> adjtime (2)              



NAME    [Toc]    [Back]

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

LIBRARY    [Toc]    [Back]

     Standard C Library (libc, -lc)

SYNOPSIS    [Toc]    [Back]

     #include <sys/time.h>

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

DESCRIPTION    [Toc]    [Back]

     The adjtime() system call 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 adjtime() system call is restricted to the super-user.

RETURN VALUES    [Toc]    [Back]

     The adjtime() function returns the value 0 if successful; otherwise the
     value -1 is returned and the global variable errno is set to indicate the

ERRORS    [Toc]    [Back]

     The adjtime() system call 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

SEE ALSO    [Toc]    [Back]

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

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

HISTORY    [Toc]    [Back]

     The adjtime() system call appeared in 4.3BSD.

FreeBSD 5.2.1			 June 4, 1993			 FreeBSD 5.2.1
[ Back ]
 Similar pages
Name OS Title
adjtime HP-UX correct the time to synchronize the system clock
hardclock OpenBSD real-time system clock
stime Tru64 Set the system-wide time-of-day clock
resettodr FreeBSD set battery-backed clock from system time
resettodr OpenBSD set battery-backed clock from system time
resettodr NetBSD set battery-backed clock from system time
adjkerntz FreeBSD adjust local time CMOS clock to reflect time zone changes and keep current timezone offset for the k...
mdSetOrigin IRIX control origin time for synchronization
clock_secs_to_ymdhms NetBSD time-of-day clock support
todr_gettime NetBSD time-of-day clock support
Copyright © 2004-2005 DeniX Solutions SRL
newsletter delivery service