[Pipet Devel] Re: GPL/LGPL issues

Richard Stallman rms at gnu.org
Mon Sep 11 05:35:53 EDT 2000

    The first one involves a library, libdata-flow which uses plugins by opening
    other shared libraries using dlopen(). Is that considered linking? 

In general, I believe it makes a combined program.  However, in some
trivial cases maybe one could make the argument that they are two
separate programs that just happen to run in the same address space.

    libdata-flow's license is the LGPL, would it be allowed to open a GPL plugin?

Certainly.  You can link LGPL-covered code with GPL-covered code in
any fashion.

    would it be allow to open a closed-source plugin? (or both at the same time?)

I don't want to speak about the categories of "open source" and
"closed source", because that would be letting people make a mistake.
I disagree fundamentally with the Open Source Movement, and if people
think I support it, my work will all promote the wrong message.  If I
use their terminology in conversation, I will be encouraging that
problem.  See http://www.gnu.org/philosophy/free-software-for-freedom.html
for more explanation.

In the Free Software Movement we distinguish between free software and
non-free; these are not the same categories as open or closed source,
because the standards they adopted in 1998 are less strict than the
ones we use.  An open-source program is probably free software, but
you can't be certain without checking the license.  So if I used the
terms "open source" and "closed source", I would also be talking about
the wrong things.

I can give you advice about free software based on the views of the
Free Software Movement; if you would like advice from the Open Source
Movement, you have to ask them.

What I can say about the question of non-free plug-ins
is that using the LGPL would definitely permit them.

Is that a good idea?  It depends on details of the situation, but in
general I think it is a bad idea.  It is better to insist that all
add-ons must be free software.  Otherwise we will face a constant
struggle to develop free add-ons to compete with the non-free ones.

    Does the license of the program that links to libdata-flow change the answer to
    the previous questions?


    Our second issue has to do with CORBA. Is it allowed by the GPL to use CORBA to
    link a GPL'd program and a closed-source program?

I can only speak about non-free programs, not about closed-source.
However, I think that *in general* two modules that communicate
through CORBA are separate programs, so that the license of each one
does not cover the other.

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