David Taylor wrote:
On 23/08/2013 15:08, Martin Burnicki wrote:
[]
Indeed. I've just enabled the SHM refclock in the config.h file for
Windows, tried to build it with VS2008, and found that it builds after I
had fixed a tiny bug, a missing semicolon.
However, I have also no idea if it works.
David, if you want to give it a try you can simply unpack the current
-dev version. Then:
1.) Open the solution (.sln file) in Visual Studio
2.) Open the file ports\winnt\include\config.h, search for CLOCK_SHM,
and change the line
#undef CLOCK_SHM
to
#define CLOCK_SHM
3.) Edit ntpd/refclock_shm.c and look around line 177. There is a line
starting with
msyslog(LOG_ERR, "SHM MapViewOfFile ...
and at the end of this line a semicolon is missing. Just add it and the
project should at least compile.
As said above, don't know if it works, though, and don't know if there
is another program which can feed the SHM driver under Windows.
If this turns out to work I can submit the fix to the code base.
Martin
Martin,
Thanks for that - the start of good news, I hope. I can confirm your
findings - as-supplied, there is an error in ntpd/refclock_shm.c which
prevent compilation, but that's easily fixed just as you described and I
also now have an ntpd.exe which has compiled correctly. The fault
should certainly have a bug-report submitted.
OK, I can do that. This was only a tiny syntax error in the source code,
but even if this is fixed we still don't know if the SHM driver really
works as expected under Windows until somebody has tested it.
Unfortunately, I don't have any programs which could write into shared
memory, so perhaps we would need to find a simple driver (the NMEA seems
an possible choice to me as many devices can drive that) and convert it
to shared memory operation.
I don't know if that makes much sense.
I have a non-critical Windows XP box I
could test on. Would the first step, though, be to see a FreeBSD or
Linux driver converted and working in SHM mode, and then provide similar
modifications to the Windows driver?
Usually the SHM segment is fed by some other daemon/service, so if e.g
gpsd could be built under Windows as service this could be used to do
this. I don't know, though, if gpsd can also be used under Windows.
Extracting some refclock driver code from ntpd, modify it so that it
uses the SHM interface instead of ntpd's "native" refclock interface,
and putting all this into an own Windows service would be quite some effort.
Maybe it would make more sense to try to port gpsd or something similar
to Windows, if this is not yet supported.
Martin
--
Martin Burnicki
Meinberg Funkuhren
Bad Pyrmont
Germany
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