On Sat, 2010-12-18 at 05:16 +0900, Kuwahara,T. wrote:

On 12/17/10, Richard Cochran [off-list ref] wrote:

quoted

This patch adds a new mode bit into the timex structure. When set, the bit
instructs the kernel to add the given time value to the current time.

The proposed new control mode, ADJ_SETOFFSET, is logically the same as
ADJ_OFFSET with timex.constant == -INFINITY. 

I'm not sure if this is correct. Its more like settimeofday, only giving
a relative offset to jump the clock, rather then an absolute time. It
does not slew the clock over time like ADJ_OFFSET does.

 So it is possible to do
the same thing without risking forward compatibility.  (I mean by "risking
forward compatibility" that the mode bit 0x0040 may be defined differently
by the upstream maintainer anytime in the future.)

adjtimex is a linux specific interface, which is compatible but not
identical to the ntp specified interfaces. The ntp client code already
has Linux specific modifications, so I don't think we have to worry
about 0x40 specifically being reserved by the NTP client.

thanks
-john