Re: ✘"Can't find packet library")

[Gary E. Miller]

Yo James!

On Mon, 27 Jul 2020 15:18:22 -0700
James Browning <jamesb.fe80@gmail.com> wrote:

> In previous emails, Gary E. Miller <gem@rellim.com> wrote:
> > Also works on macOS:
> >
> >     Python 2.7.16 (default, Apr 17 2020, 18:29:03)
> >     [GCC 4.2.1 Compatible Apple LLVM 11.0.3 (clang-1103.0.29.20)
> > (-macos10.15-objc- on darwin Type "help", "copyright", "credits" or
> > "license" for more information.  
> >     >>> import ctypes.util
> >     >>> ctypes.util.find_library("gpsdpacket")  
> >     'libgpsdpacket.dylib'  
> 
> That is setup up by packet.py.in lines 48-50 & 61-66 with Cthulu code
> instead of hardcoded magic values.

Yes, and I see no hardcoded magic values in my test (above) either.

> > Is there a good reason for gps/packet.py to work so hard?  
> 
> Aside from Python not working hard enough?

I can open the proper file in 3 lines, the current code is much larger.
Of course my code will get bigger with GPSD_HOME and looking in the cwd.

> > Seems to me that the program should look for the lib:  
> 
> >         1) in GPSD_HOME
> >         2) in current directory
> >         3) using ctypes.util.find_library()  
> 
> Seems to fail when installed in /usr/local (see previous crotch
> punching).

Works for me.  Does this not work for you:

macOS:

    >>> import ctypes.util
    >>> a = ctypes.util.find_library("gpsdpacket")
    'libgpsdpacket.dylib'
    >>> s = ctypes.CDLL(a)

Linux:

    >>> import ctypes
    >>> import ctypes.util
    >>> a = ctypes.util.find_library("gpsdpacket")
    >>> a
    'libgpsdpacket.so.27'
    >>> s = ctypes.CDLL(a)

> would probably fail if running from ${repo}/tests/daemon
> or other ridiculousness.

Which is what GPSD_HOME is supposed to fix.  gps/packet.py lines 43-46

I have not looked at that code yet.

> > And, instead of looking for the exact lib version, just check the
> > major version after loading it.  
> 
> Currently, checks for the exact version when running from the repo and
> no version checking for distro installs.

But the problem case is a git install.

Given the continuing version problems (3.17) some form of version
checking, somewhere, is required.

> > Does that sound right?  
> 
> My compass is broken and I do not feel like implementing it like that.

And the code is broken, for the git install case, so it has to get
changed.  I'll make the changes, but as I am new to this, I want my
thoughts in the open for comments.

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

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