BSD / GPL compatibility - Derived vs. Fair Use

Joe Mason jcmason at
Wed Feb 16 17:21:44 UTC 2000

On Tue, 15 Feb 2000, David Johnson wrote:

> In terms of copyright law (and not in terms of programming usage), is an
> application that links to a library considered derivative? I would say that
> static linking is derivation and runtime linking is not. But I'm not sure about
> dynamic linking. RMS brings up some good cases against it, but on the other
> side there are the arguments that the two are created and distributed
> separately, and that the only differences between dynamic and runtime linking
> are purely mechanistic.

It's unclear, and this is one of the weaknesses of the GPL that I
mentioned earlier.  A lot of companies avoid using it because of just
these kinds of questions.  In contrast, the MPL is careful to define every
term it uses, which is why corporations which might be targets for
litigation tend to use it when possible.

If the next version of the GPL were to include a section saying, "For the
purposes of this license, a 'derivative work' is defined as..." it would
go a long way toward clearing up these problems.


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