Fw: Query about GNU-GPL

[Laurence Finston]

On Wed, 23 Mar 2005, Alfred M. Szmidt wrote:

>    For example, my package uses GNU Bison and I include a Bison input
>    file in my sources.  If I choose, I can distribute Bison with my
>    package, since its license permits me to do so.
>
> You are confusing "derived" and a compilation, which this would be.
> It is the same thing as distributing a GPL program on a CD with a
> non-free program.

My point was that using and/or distributing it with my package would not
combine them into a single package.

>
>    Another example would be if I were to use the libplot library
>    supplied as part of the GNU plotutils package.  Here, I would
>    include its header files in my sources and link to the library when
>    compiling.  In this case, the packages are mixed more intimately,
>    but the comments above still apply.
>
> Your comments don't apply to this case at all,

In this case, the license of GNU plotutils permits me to use it in
combination with my package, and there is no conflict with the license of
my package.  The licenses are, in fact, the same, but they could differ,
as long as this use did not conflict with either of them.

> linking a non-free
> program with a GPL library is infact illegal.

This is not the case I was discussing.  I was discussing the case
of a free program linking with an unfree library.  The license of
that library might permit me to link to it while still being unfree
in other respects, using the FSF's definition of freedom.
I do not believe I would be breaking any law by
linking my program to it.  I certainly wouldn't distribute it with
my package without checking with the FSF first.

The following links may be of interest:
http://www.gnu.org/licenses/gpl-faq.html#FSWithNFLibs
http://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs

> Since the non-free
> program will become part of (derived work) the library and vice versa!

A program that includes a library does not become part of the
library, but the text at
http://www.gnu.org/licenses/gpl-faq.html#MereAggregation
seems to indicate that the library becomes part of the program.
I don't entirely agree with this interpretation, and would check with
the FSF if it ever became relevant for me.  However, I have no plans to
ever link free code that I write with unfree libraries.

> Merley including a GPLed header in a non-free program is _also_
> illegal, because of the same reason.

Perhaps, but this isn't my problem.  I was trying to help someone
who wants to write a free program.

> Think what happens when the C
> preprocessor does its magic, and you will see why,

I don't understand your point.  (I don't find CPP particularly
magical, myself.)

>
>    I am pretty certain that merely linking to a library does not give
>    the owners of that library any rights over my code.  I am also
>    pretty certain that linking two packages, in the literal sense of
>    using a linker to generate a file of object code, does not unite
>    the packages in a legal sense.
>
> Sorry, but you are wrong on both accounts.  See the GPL FAQ for the
> offical answer.
>

I think these entries support my point of view, but I really
recommend asking at the FSF to be sure before actually
distributing code.

http://www.gnu.org/licenses/gpl-faq.html#FSWithNFLibs
http://www.gnu.org/licenses/gpl-faq.html#GPLIncompatibleLibs

Laurence