Re: [gpsd-dev] Adding additional parameters to gps_data_t structure

[Gary E. Miller]

Yo Sharmila!

On Tue, 2 Jul 2019 21:00:29 +0530
Sharmila <address@hidden> wrote:

> I am using gpsd deamon for fetching the GPS data from ublox module. I 
> have added velN (
> North velocity component) , velE (East velocity component) and height 
> (Height above ellipsoid) parameter in gps_data_t fix structure.

Interesting.  First time I ever heard someone wants velN, velE and velU.
Sounds worthy of adding for version 3.20.  What is your use case?

Except it does not belong in gps_data_t, but in gps_fix_t, as it is
part of a fix.

Then json_tpv_dump() in gpsd_json.c needs to be modified to send the data
along when valid (not NAN).  Then json_tpv_read() in libgps_json.c need
to be able to decode the new JSON items and put back in gpsd_fix_t.

> After adding the above mentioned parameters and increased the debug
> level I got the below prints from driver.

Well, a lot more to do that just adding thing.  But that is a start, can
you send a patch with that part?  The new parameters need to be set to
NAN is not valid, likely in gps_clear_fix() in gpsutils.c

> But the data doesn't seem to be transfer or handled in application as 
> expected since I am getting unexpected values in the application.

Hard to say what went wrong without seeing what you did.  Send a patch
and I'll tell you what to add to it.  We can do this one step at at time.

> Also as a part of debugging process we tried to enable 
> libgps_debug_trace() , but I am not able to get the prints from 
> libgps_sock.c and libgps_core.c file. Kindly help us to enable the 
> libgps_debug_trace().

And how did you try to enable it?  I can't guess what you missed without
knowing what you did.

RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
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