Re: open SHM data only after cgps start

[Gary E. Miller]

Yo Hans!

On Fri, 5 Feb 2021 18:52:19 +0100
Hans Kurscheidt <lve0200@gmail.com> wrote:

> I am now more than ever convinced that there's an issue in gpsd!

I think Fred has the answer, he knows much more about systemd(umb) tha I do.

> 1): fresh & clean boot; sudo lsof | grep /dev/ttyACM0 (my device
> (ublox 6 via USB)) => nothing open.

Not so fast.  As Fred said, systemd does not start gpsd until the
first network client connection.  SHM connections are ignored by
systemd(ubmer).

You can verity this way:

netstat -apn | fgrep :2947


> 2) starting my app; sudo lsof | grep /dev/ttyACM0 (my device (ublox
> 6)) => nothing open  

Ditto above.
 
> starting cgps in parallel; sudo lsof | grep /dev/ttyACM0
> gpsd        700           nobody    9u      CHR      166,0 0t0      
> 14619 /dev/ttyACM0
> 
> my app starts to receive data as well, like cgps.

Ditto above.  Fred explained this.

> after a while, my app does not receive anymore data (most likely when 
> buffer has become empty); sudo lsof | grep /dev/ttyACM0 (my device 
> (ublox 6)) => nothing open.

No.  Systemd(umbest) say no network connections and killed gpsd.

RGDS
GARY
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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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