Manual page for ADJTIME(2)
adjtime - correct the time to allow synchronization of the system clock
struct timeval *delta;
struct timeval *olddelta;
makes small adjustments to the system time, as returned by
advancing or retarding it
by the time specified by the timeval
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
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-zero,
then 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.
is restricted to the super-user.
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.
The following error codes may be set in errno:
An argument points outside the process's allocated address space.
The process's effective user ID is not that of the super-user.
date(1), gettimeofday(2), timed(8), timedc(8),
TSP: The Time Synchronization Protocol for UNIX 4.3BSD,
R. Gusella and S. Zatti
Created by unroff & hp-tools.
© by Hans-Peter Bischof. All Rights Reserved (1997).
Last modified 21/April/97