[ntp:questions] Start of new GPS 1024 week epoch

Rob nomail at example.com
Tue Aug 27 19:05:42 UTC 2013

Martin Burnicki <martin.burnicki at meinberg.de> wrote:
> What I meant is the usage of CreateFileMapping() and MapViewOfFile() for 
> shared memory segments, as it is done in ntpd's refclock_shm.c.
> We are using this in the Windows driver package for our PCI cards, but 
> this usage is not related to NTP. AFAIK this is supported in all Windows 
> version at least starting with NT.
> Ntpd has already implemented this (which I also didn't know until 
> recently), and it should not be too hard for something like gpsd to 
> implement this also, if this han't already been done, yet.

Looking in the most recent ntpshm.c I see only the calls to shmget
and shmat.  But I think you are right, it should be quite simple to
add a compilation conditional and replace it with mapping calls similar
to what is found in the Windows port of ntpd.

However, it could also be that libraries that come with cygwin already
do that translation.

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