Re: [gpsd-users] how to send control string (command) to device with <CR><NL> included in string

[Gary E. Miller]

Yo Howard (US COM)!

On Mon, 12 Sep 2016 22:33:24 +0000
"Stoner, Howard (US COM)" <address@hidden> wrote:

> >> From reading the gpsd daemon documentation, it sounds like sending
> >> a message via the Control Socket connection, of the form 
> >> "!/dev/ttyxx=$PMTK..." should do this.  
>   
>  I can probably mod the '!' command within handle_control to remove
> the 'snarfline()' call for my purposes, since I know that whenever I
> use that command I will be supplying exactly what the device needs in
> its command string..

I'm not sure anyone uses the '!', but I'm not sure no one does.  So
best to come up with some compatible improvement.  Maybe '!!' for a 
raw command.  Maybe hex encode the "\n", etc.

Have you tried to hex encode the trailer?  That would be back compatible.

> > Well, that would be a bug.  Sadly also a dark and dusty corner of
> > the gpsd code.  Some people have gotten that to work, but never fed
> > back their procedure.  But any reason not to send the string before
> > starting gpsd?  
> 
> My intent is to handle 'mode' changes in the gps device, particularly
> power standby / restart commands, without stopping and restarting
> gpsd, but I may be able to handle it with either a shutdown/restart
> of gpsd, or via the control socket mod referred to above.

Yeah, very useful, and supposed to already work.  Someone else over
the weekend wanted to poll the GPS for somthing else.  So the need is
cleaerly there for a way to slip in things.

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

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