[ntp:questions] new driver development

Bruce Lilly bruce.lilly at gmail.com
Fri Apr 1 22:06:42 UTC 2011

On Mon, 28 Mar 2011 04:56:24 +0000, Dave Hart wrote:

> It hasn't come up there, but I've been thinking about backwards
> compatibility in an updated refclock_shm which supports the existing
> SysV shared memory, struct shmTime, and access methods for units 0-3,
> and uses POSIX named shared memory with new layout and access semantics
> for units 4 and up.

I presume that means (in each of the driver functions) something like:

if (unit < 4) {
   /* do SHM driver stuff (SVID) */
} else {
   /* do new stuff */

Is that correct?

> I encourage you to join hackers at lists.ntp.org and/or create a bug report
> at http://bugs.ntp.org/ and share what you've done, if you want to see
> some part of it make it into an updated refclock_shm.c.

I'm already subscribed to more mailing lists than I can keep up with!

If I were continuing with my original plan or redoing it, I'd do things
differently from what I have done.  But I have another plan which can
avoid the word size/endianness/locking issues altogether, and it provides
for future precision beyond the nanosecond level.  More details to follow
in due course.

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