Re: [gpsd-dev] Example code for libgps using shared memory

[Gary E. Miller]

Yo Fred!

On Fri, 17 Nov 2017 14:53:34 -0800 (PST)
Fred Wright <address@hidden> wrote:

> On Wed, 15 Nov 2017, Gary E. Miller wrote:
> > On Wed, 15 Nov 2017 18:44:24 -0800 (PST)
> > Fred Wright <address@hidden> wrote:
> >  
> > > > > Anything that requires setting LD_LIBRARY_PATH is broken.
> > > > > Did you rerun ldconfig after the install?  
> > > >
> > > > I disagree.  /usr/local/lib is not in LD_LIBRARY_PATH by
> > > > default, and the FHS has us install in /usr/local/llib to not
> > > > step on system libraries.  
> > >
> > > You're missing the point.  LD_LIBRARY_PATH shouldn't be used in
> > > normal circumstances *at all*.  See, e.g.:
> > >  
> > Uh, no.  read the standard; FHS.  
> 
> This isn't about FHS; it's about the use of LD_LIBRARY_PATH, which is
> a mostly orthogonal issue.

Well, for me, it is all about the FHS, nothing more.  As long as gpsd
compiled by the user goes in /usr/local/ then I'm happy here.

LD_LIBRARY_PATH is just a distro specific detail that we may need to
help the user to get right on his distro.

> > Your links are for ssytem stroinstalled libs.  
> 
> No, they're not.  Read them.

Been there done that.  Been reading them since before they were even
standards.

> --------------------------------------------------------------------
> Note that it has no problem finding libgps in /usr/local/lib, without
> LD_LIBRARY_PATH.

Cool.  Not the case on all UNIX, not the caser on Gentoo, but nice when
you got it.

> The shortest path to the cheese isn't necessarily the correct path to
> the cheese. :-) Many software bugs are due to failure to appreciate
> that concept.

Lost me.  All you did was make me hungry.

> > ​If ​LD_LIBRARY_PATH shouldn't be used in normal circumstances *at
> > all*, how could I use the libgps?  
> 
> If libgps is properly installed before building your program, then
> simply including "-L/usr/local/lib" in the linker options should be
> sufficient to locate the library directory, both at link time and at
> run time.

Not on Gentoo, and other distros, if it works for you great.

> Testing with *uninstalled* libraries may require the use of
> LD_LIBRARY_PATH, but that's a special circumstance and not the normal
> use case.  And you need to be careful of installing programs built
> with LD_LIBRARY_PATH set, since they may inherit a dependency on it.

Not sure why you bring it up.  Once again, I'm complaining about
failure to comply with FHS.

All I care about here is that when gpsd is compiled by the user, that
its stuff gets installed in /usr/local, not /usr.

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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