Re: Using non-GPL libraries in a GPL program

[Tim Smith]

In article <85bq2joccj.fsf@lola.goethe.zz>, David Kastrup <dak@gnu.org> 
wrote:
> > Same with the concept of "distribution".  Whatever it is the FSF talks
> > about when it talks about software distribution seems to have little
> > connection to what the copyright law means when it uses that term.
> > Remember when the FSF was claiming that giving someone code that can
> > be linked with GPLed software is an implicit distribution of the GPLed
> > software, even though it is up to the recipient to decide if they want
> > to get and link with the GPLed software, or get and link with other,
> > non-GPLed software?
> 
> It never claimed anything like that.  You are confusing this with
> contributory infringement: doing software distribution in a manner that
> _requires_ the recipient to perform steps _on behalf_ of the distributor
> without which he would not get what he paid for.

Incorrect.  Given two libraries that both contain a function to do a 
given task, the FSF claimed that distributing this source code:

   #ifdef USE_LIBRARY_A
      function_from_library_A( ...arguments... );
   #else
      function_from_library_B( ...different_argument... );
   #endif

so that the recipient can decide which library they prefer to use,
required that this source be GPLed if library B is a GPL'ed library.

The program was fully functional if the user compiled it to use library 
A.

The author of the code finally made a new library, that had the same 
interface as library B, but that was public domain (I believe it was 
just a wrapper for library A).  The FSF then shut up, because now there 
was a non-GPL library that had the same interface as the GPL library, so 
there was no longer an "implicit distribution".

As far as contributory infringement goes, there cannot be contributory 
infringement without direct infringement.  If there is no one who is a 
direct infringer, there is no infringement for one to be a contributory 
infringer to.  GPL allows me, the end user, to link GPL code with 
anything I want to, as long as I'm not going to distribute that.  You 
can do anything you want that helps me do that, in it is *IMPOSSIBLE* 
for your actions to be a contributory infringement.

> 
> > But only if the GPLed and non-GPLed software have different
> > interfaces?  If they have the same interface, then it is no longer an
> > implicit distribution.
> 
> You are making terms up as you go.  When they have the same interface,
> linking the GPLed library in stops being a necessary step for the
> recipient for getting working software.

It was never a necessary step.  The software was fully functional 
without using any GPLed libraries.

-- 
--Tim Smith