[Pipet Devel] Re: GPL/LGPL issues

[Richard Stallman]

    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.

    If
    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?

Yes.

    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.