Re: Change from 3.23 to 3.24 - program doesn't work?

[Mike Tubby]

On 22/06/2022 21:45, Gary E. Miller wrote:

> Yo Mike!
>
> On Wed, 22 Jun 2022 20:52:26 +0100
> Mike Tubby <mike@tubby.org> wrote:
>
> > > > Its a work project, so I would have to remove some code to protect
> > > > the innocent.  
> > > >           
> > > You get paid, we work for free?  Does not seem fair.  Try to give
> > > back in some way on the future.  
> > >         
> > I'll sanitise and post later ...
> >       
> Sadly, people tend to sanitize out their broken pars...
>
> > > > the code that generates this error is in my reader:  
> > > >           
> > > That is NOT an error, read what it says.  You have an API mismatch,
> > > and you either need to change your code for the new API, or stick
> > > with the old gpsd.  
> > >         
> >
> > I think we're at slightly crossed purposes.
> >       
> Clearly.
>
> > I am using a matching gpsd version 3.22 and libgps from Debian
> > (actually Devuan 4.0) and it works as long as I don't attempt to
> > check.
> >       
> 1) 3.22 is old, 3.24 is current
> 2) The Debian binary is not from us.
> 3) If you gpsd and libgps version match, then you will not fail the version
>    check.
>
> > If I try to check then the things I have to play with appear to be:
> >
> >      1) the version_t structure; and
> >      2) the pair of #defines for API major and minor versions
> >       
> Don't touch those.  That is like fixing a house fire by changing the
> street address.
>
> > So, what what a program has available at run-time I don't see how I
> > can ever do a valid check since
> >
> >      proto_major (value 3) != API major (value 11)  && proto_minor 
> > (value 14) != API minor (value 0)
> >       
> That can only happen if you have multiple versions of gpsd installed.
> Don't do that.
>
> > I fully understand that if I install matching versions of gpsd/libgps 
> > everything will work,
> >       
> So, have you?  Or have you not?
>     
    
    I do not have mis-matched versions at this time.  The gpds version
    3.22 and libgps match, **BUT** I am trying to code to detect
    mis-matched versions in the future.
    
    
> > but what comparisons do I perform to check if 
> > things are out of step,
> >       
> None,  fix the root cause: mismatched versions.
>     
    
    I don't actually have mis-matched versions I want to check for
    possible mis-matched versions in the future.
    
    The problem is that if I test the only things that I can test it
    tells me that it is mis-matched when it is not, hence my questions
    to understand if I am testing the correct things?
    
    And right back to the issue with version_t in the GPSD/libgps code,
    i.e. /usr/include/gps.h where version_t is defined:
    
      struct version_t {
          char release[64];                   // external version
          char rev[64];                       // internal revision ID
          int proto_major, proto_minor;      
          // API major and minor versions
          char remote[GPS_PATH_MAX];          // could be from a remote
      device
      };
      
      
    highlighted in red - the variable names are 'proto_major' and
    'proto_minor' but the comment says API major and API minor.
    
    When I compare the #define for API_MAJOR_VERSION (which is 11) to
    proto_major (which is 3) they do not match.
    
    What I need to know is should they match?
    
    I have created a test/demo program based on my code that includes
    the whole of my low-level GPSD client module gpsd.[c,h], my cross
    platform timer routines (which are needed) and test.c - a README
    file exists to aid the reader.
    
    
    Regards
    
    
    Mike
    
    
> > for example if gpsd has been upgraded but
> > libgps has not ... ?
> >       
>     
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
    
> That you are screwed.  Don't do that.
>
> 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
>

gpsd-test.tar.gz
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