Re: [gpsd-dev] ✘GPSD_API

[Gary E. Miller]

Yo Fred!

On Thu, 14 Apr 2016 12:20:20 -0700 (PDT)
Fred Wright <address@hidden> wrote:

> On Thu, 14 Apr 2016, Gary E. Miller wrote:
> 
> > Thanks for the confirmation.  Now I am hitting my head on a wall as
> > when I checn gpsdata_t my scons check fails.
> >
> > Processing test/daemon/passthrough.log
> > gpsd:ERROR: shmget(0x47505345, 9512, 0666) for SHM export f ailed:
> > Invalid argument
> >
> > Which usually means mismatched shmget() sizes, but I can't figure
> > out why the test harness is using the old sizeof(shmexport_t) and
> > not the new one.  Deleting all system gpsd libs and starting from a
> > fresh git clone, plus the one cchange, is no help.  
> 
> Do you have an ntpd running with a SHM source enabled?  BTW, changing
> the size without breaking NTP might be an issue.

My use case is 'scons check' which uses shmget().  The SHM that
scons check uses is not the same SHM that NTP uses.


> Also, if by "fresh git clone" you mean re-cloning the repo, that's
> almost certainly unnecessary since "git clean -dxf" gives you
> essentially the same result.

Not really, I also delete all system gpsd components.  That has
bitten me in the past.  So I go really clean.

And the git clean man page imprlies you need to double up on the -f, 
like this:  git clean -dxff.  To hard for me to remember, I just delete
everything and I know I got it right.

> > I like that strategy, you know the actual counts will always match
> > the totals.  Carrying core data, and derived data, often leads to
> > discrepancies.  
> 
> Well, a count that actually matches the data being delivered might be
> useful to an application that wants to know how big a buffer to
> allocate before scanning the data.

In the gpsd case, the sat arrays are fixed size, so we just care about
which items are actually used.

> Or to an application that only
> wants to report the counts and doesn't care about the individual
> items at all.

Which a gpsd json client now can not do.

But I agree, each use case may have its different priorities.

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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