Re: Change from 3.23 to 3.24 - program doesn't work?

[Gary E. Miller]

Yo David!

On Mon, 20 Jun 2022 08:12:11 +0100
David Taylor <gm8arv@yahoo.co.uk> wrote:

> On 20/06/2022 07:41, Gary E. Miller wrote:
> > Yo David!
> > 
> > I can't see how that ever worked.  Your program does not check
> > if the receiver JSON has the data you are trying to read.
> > 
> > Take a look at example.c for ideas on what is missing.  
> 
> Thanks, Gary.  The program has worked correctly with several
> different ublox receivers on multiple RPi cards.

That can happen when you don't follow the rules, but to work for
all receivers, you have to follow the rules.

> Has something changed between 3.23 and 3.24 which might have caused
> problems with this program? 

Yup, message order has changed, yet again.  gpsd never guarantees JSON
message order, only that the data from each epoch is separate.

> Have the data structures changed?

Every version.  That is why you need to recompile for each new gpsd version.

>  How
> can I check the API level?

Look at the top of include/gps.h.  BUT, if you follow the gpsd rules,
checking for the data you want in the message you got, then you do not
need to.

RGDS
GARY
---------------------------------------------------------------------------
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
        gem@rellim.com  Tel:+1 541 382 8588

            Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin

pgp7NT4zYmEPt.pgp
Description: OpenPGP digital signature