[erlang-questions] GNU GPL, MIT, BSD and compatibility

Richard Carlsson <>
Fri Apr 11 16:46:54 CEST 2008


David-Sarah Hopwood wrote:
> "A" is correct. But the GPL is a red herring here. I can take any
> MIT-licensed code and redistribute it with the additional license term
> "to use this code, you must give me your first-born child", for example [*]
> (enforcability aside). This is not a problem, primarily because someone
> can still use the code distributed under the original license, and not
> give me their first-born child. The fact that the original copyright
> holder(s) chose an MIT or BSD-like license entails that they accepted
> the possibility of redistribution under any more restrictive license.

Yes, MIT was perhaps not the best example, but it seemed to be the
most uncomplicated. A better example (to our tormented readers) would be:
You are the copyright holder of product X, which you license under the MPL
(not GPL-compatible) and you don't (for some reason) want your code to slip
into GPL-land for love or money. But some way or another, you use a GPL:ed
library Y in your product, and ship it. Some third party browses your code,
sees your use of Y, and now demands that you release all of X (at least
the version that uses Y) under the GPL. If your refuse to do that (you do
have the right to do it if you want to), you would be violating the GPL.

But that would be way too much to write. :-)

     /Richard





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