Fw: Query about GNU-GPL

Alfred M. Szmidt ams at kemisten.nu
Wed Mar 23 13:57:39 UTC 2005

   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.

   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, linking a non-free
program with a GPL library is infact illegal.  Since the non-free
program will become part of (derived work) the library and vice versa!
Merley including a GPLed header in a non-free program is _also_
illegal, because of the same reason.  Think what happens when the C
preprocessor does its magic, and you will see why, the linker case is
a bit more subtle, for the static library case, it is quite simple
since the end result will contain the GPLed code.  In the dynamic
library case it is a bit harder; but it is easy to see if you just
remove the library and then try to use the program (and the fact that
the non-free program will infact contain bits from the headers which
are copyrighted).

   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.

   If anyone wants an official answer to this or similar difficult
   questions, I suggest he or she contact `licensing at fsf.org'.

Or just look at the GPL FAQ which already has answers for this; but if
that would fail for whatever reason, then asking the FSF people is a
good idea.


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