[ntp:hackers] Leap stuff

David L. Mills mills at udel.edu
Mon Jul 2 20:22:34 UTC 2007


Warner,

There are mechanisms to export data from the ntpd daemon to another 
process, but I am not expert to do that. It could be done using a pipe 
or shared memory or the get_ntptime() system call, which works now in 
FreeBSD and perhaps other systems, but not in Solaris or Tru64. I 
designed the syscall interface so an application can get the data it 
needs to evaluate the time quality, as well as the TAI offset.

It might well be that at least some GPS receivers can return the GPS 
timescale offset, from which the TAI offset can be deterined. If so, 
that could be used for the system TAI and downloaded via Autokey. 
However, future leaps could not be determined until noticing that the 
change, so the behavior could be jumpy.

Dave

M. Warner Losh wrote:

> Dave,
>
> With the changes, would it become possible to get the TAI-UTC offset
> from NTP directly? That doesn't seem to be possible at the moment,
> but would be very handy for a variety of applications that have good
> connectivity to, say, GPS, but bad network connectivity.
>
> Warner




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