[Xastir-dev] Fun with gpsd... not!

[clayj at nwlink.com]

Ouch!  You're making my head hurt!

I just started fooling with GPSD to do PPS on my Ubuntu system.  My $5
OnCore (well, OK, $50 by the time I added the TAPR board and an antenna)
finally gave up after about 8 years of faithful service.

Good luck!

Clay
N7QNM


>
> I started down the path of writing to the new API that GPSD clients
> are supposed to use.  The new autotools tweaks work to detect
> whether the libgps and gps.h files are in place.  To get this to
> work properly I had to rename our own src/gps.h to src/xastir_gps.h
> (not checked in yet).
>
> Now I'm in the middle of interface.c changes and find that my
> version of libgps is pre-2.90 and therefore doesn't have the
> gps_stream() call that the GPSD web pages recommend we use.
>
> In other words I'm coding to an API that just changed within the
> last few months and the API we've been using for the last six years
> is no more, yet my systems have an API that's in-between those two.
>
> I could code for three different GPSD API's:
>
> 1) Socket connect + send "R\n\r" (as we've done since 2004).
> 2) Pre-2.90 API that a lot of OS'es currently use.
> 3) Post-2.90 API.
>
> In order to support this I may have to add more autotools tests to
> check whether libgps is present, then to check which version of the
> API we have.  I'm considering skipping protocol #1 above and
> requiring libgps for GPSD support from now on, simplifing our code.
> I think systems as old as fall of 2004 would be able to still use
> GPSD this way, as long as they installed the gpsd client libraries
> which include libgps.
>
> The code in interface.c is going to get even uglier.  If anyone can
> think of a good way to isolate this other than a bunch of #ifdef's,
> please let me know.
>
> I'm also wracking my brain over how to do the libgps API code in
> separate threads like the rest of the interface code is written to
> support.  Protocols 2 & 3 above appear to be set up for us to read
> directly out of a structure when an "OK" flag is set for us, instead
> of reading periodically from a socket stream as we do now.  All of
> the interface.c code is set up to have a read thread and a write
> thread to talk to each device or socket, but the libgps API takes
> care of much of that for us.  I'll probably have to separate out the
> libgps code from the rest of the interface.c code now as it's done
> so differently.
>
> --
> Curt, WE7U.                         <http://www.eskimo.com/~archer>
>     APRS:  Where it's at!                    <http://www.xastir.org>
>    Lotto:  A tax on people who are bad at math. - unknown
> Windows:  Microsoft's tax on computer illiterates. - WE7U.
> The world DOES revolve around me:  I picked the coordinate system!"
> _______________________________________________
> Xastir-dev mailing list
> Xastir-dev at lists.xastir.org
> http://lists.xastir.org/cgi-bin/mailman/listinfo/xastir-dev
>
>