Re: GPSD Service: open SHM data only after cgps start

[Gary E. Miller]

Yo Hans!

On Thu, 4 Feb 2021 19:59:51 +0100
Hans Kurscheidt <lve0200@gmail.com> wrote:

> I'm Hans, German Engineer, retired, living in France. This is my 1st 
> post, here.

Welcome!

> Running GPSD 3.16 on an SunxI H2+ OrangePi-Zero under Debian Jessie. 
> Couldn't get anything newer for this distribution.

3.16 is from January 2016.  And if it is from a package, not from us.
3.22 is current.  A lot of changes between the two.  Easy to build from
source.

A lot of features of newer GNSS receivers are not supported in 3.16.

> I use a CPP thread to open and collect GPS data via the gpsd.service.

I do not recommend running gpsd under systemd(umb).  To debug it
we need to see the contents of your gpsd.service file and thse two files:

    /etc/default/gpsd
    /etc/sysconfig/gpsd


> Everything works fine, as long as I start e.g. cgps before my 
> application;( Once opened, I can close it). If I don't start cgps,
> the open statement in my app executes w/out error, but the subsequent 
> gps_read fails w/ Error 88 "unknown Error" forever.

I'm gonna guess you forgot to  set the "-n" flag to gpsd.  Read the
man page on that.

> It looks like the 
> open statement does not really open the device??

It does, but then you have to wait for the autobaud, receiver protocol
detection, etc.

> Any suggestions?

Update to 3.22, add the "-n" flag.

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

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