Re: Bug #189164: libdbd-mysql-perl uses GPL lib, may be used by GPL-incompatible apps
Steve Langasek wrote:
>This assumes that the FSF's interpretation depends on the claim that
>dynamic linking creates a derived work. While varies parties have
>claimed this at one point or another, I have argued that the
>dynamically linked work is under the purview of the GPL by virtue of
>the license terms alone, *if* you are distributing the GPL library in
>question, which is always the case for Debian.
Well, this statement is simply wrong, and I'll devote the rest of this
email to explaining why.
If the dynamic linking does *not* create a derived work, you are
distributing two works:
A. The new program which links to the GPL'ed library
B. The GPL'ed library which is linked to
Not one work. A "mere aggregaton" of two works.
Under the GPL, the library B is distributable under section 3, using
either the written offer (b) or the distribution of source code (a), and
the source code for the library can be distributed under section 1.
There is no restriction on the distribution of B with other works. In
fact, there's an explicit statement that there's no such restriction
(Section 2, final paragraph). So the GPL imposes no restriction on the
distribution of A and B together. Note carefully that *all* the
restrictions in the GPL (except for the very mild section 1
restrictions) are stated in terms of "incorporating parts of the
Program", "as part of a whole which is a work based on the Program",
etc., all of which are terms refering to the creation of a derived work.
Steve said:
>"You have no say in it, it's not a derived work" is a
>null argument, because as distributors we must accept the terms of a
>license that *gives* them a say in it.
Wrong. The license, in the case of the GPL, *doesn't* give them a say
in it.
Some other, theoretical, license, *could* impose such a restriction (a
la the BSD advertising clause), but the GPL simply *doesn't* impose such
restrictions.
The "dynamic linking imposes GPL" is, fundamentally, based on the idea
that dynamic linking creates a derived work. I'm quite sure the FSF
lawyers will agree with me on that.
Furthermore, it is not within the rights of the copyright holder to
decide unilaterally what constitutes a derived work. I believe that is
considered to be a matter of facts, to be established by court cases and
precedents.
Respecting the FSF's *opinion* that dynamic linking creates a derived
work is perfectly sensible and wise. (Hey, they could be legally
correct!) Claiming that the GPL somehow imposes itself on works linked
with even if linking *doesn't* legally create a derived work is just
plain wrong.
--Nathanael
Reply to: