[quagga-dev 11480] non-GPL code calling and depending on GPL libzebra
paul at jakma.org
Thu Sep 11 07:56:46 BST 2014
My understanding of software copyright and GPL licensing is that when you
have code A that has a specific dependency on code B, then the author of
code B has a copyright claim over code A. The author of code A must then
conform to the conditions of any licence given by the author of code B for
code B, so far as copyright law demands (aside: which is quite far, IMLU).
E.g., if code A calls, uses and depends on Quagga's libzebra, then code
A must conform with the GPL licence of libzebra where copyright applies
(e.g. copying code A, in source or binary form, outside of exceptions
provided by copyright law).
If code A is distributed under, e.g., a BSD licence, then this would not
conform with the GPL licence applicable to it, as the BSD licence is not
compatible with the GPL in this way.
That is my understanding of things. I havn't had reason till now to think
it was wildly off the mark. It'd be useful to hear of very concrete legal
opinion to the contrary.
Next, I'm curious what issues could arise if Quagga started distributing a
daemon under a BSD licence, with that daemon calling libzebra. If my
understanding above is correct, is this just a triviality that can be
ignored? What are the consequences to Quagga? Are there consequences for
Opinions, examples, etc., would be very much welcomed.
1. Not an exhaustive list of how code A might come to depend on libzebra.
2. My understanding is that distributing modern-BSD licensed code as GPL
is permissible, as the GPL meets the requirements of the modern-BSD
licence, where modern-BSD licence is without the advertising clause.
Paul Jakma paul at jakma.org @pjakma Key ID: 64A2FF6A
You will be held hostage by a radical group.
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