Re: open SHM data only after cgps start

[Frank Nicholas]

Why not use init?  It’s worked since the beginning of Unix.  Unfortunately, on 
your system with SystemD, it is probably “emulated” and managed by SystemD…

Most Linux distort still support startup scripts.  When you use them, you 
*know* what is happening.

Thanks,
Frank

> On Feb 5, 2021, at 2:01 PM, Hans Kurscheidt <lve0200@gmail.com> wrote:
> 
> Yeah, but help me,
> 
> if I need something like gpsd running from cold boot, what shall I do in my 
> app? Calling system("gpsd ....") during init ??
> 
> 
> Am 05.02.2021 um 19:58 schrieb Frank Nicholas:
>> Most people who have a long history with Unix do not like SystemD - it tries 
>> to do too many things and does most of them poorly.  It often gets in the 
>> way - THIS HAS BEEN ALL OF YOUR ISSUES.
>> 
>> I avoid systems with it, if I can.
>> 
>> Thanks,
>> Frank
>> 
>>> On Feb 5, 2021, at 1:56 PM, Hans Kurscheidt <lve0200@gmail.com> wrote:
>>> 
>>> Hi,
>>> 
>>> mails are crossing!
>>> 
>>> Last question, I don't know what you mean with systemD (UMB) (UMCest) etc.
>>> 
>>> RGDS
>>> 
>>> hk
>>> 
>>> 
>>> Am 05.02.2021 um 19:51 schrieb 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
>>>> ---------------------------------------------------------------------------
>>>> 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