[erlang-questions] Licensing an Erlang/Emacs Lisp project

Volodymyr Kyrychenko <>
Sat Sep 1 00:59:30 CEST 2012


Thomas Järvstrand wrote:

> Thank you for your reply.
> 
> Correct me if I'm wrong but as far as I've understood it, writing a
> program to be run in the erlang vm is fine since that qualifies in GPL
> as being system libraries. The problem supposedly is that the moment you
> call one of the otp standard libraries you're toast since that is the
> equivalent of dynamic linking, meaning that in practice it's not really
> feasible to license an Erlang project under GPL?

GPL as a strong copyleft license requires you to make your project
licensed under GPL. That does not mean that code licensed under other
licenses will be relicensed under GPL, this actually is opposite of
being true.

I'll show you an example. You combining larger work with:

erlang (Erlang PL).
your_library (your total control over rights on code)
libraryX (licensed under GPL).

So your larger work as a whole have to be GPL (with its parts under
their own licenses).
your_library could be licensed as GPL or any other GPL compatible
license in a larger work.
Any modifications or parts of the code governed by Erlang PL should be
licensed under Erlang PL in the combined work that as a whole is
licensed under GPL.

The issue with linking your referring to arises when you calling GPL
licensed library from the project you dont want to be GPL licensed, not
the opposite. So if you call otp from GPL - that's fine. But if you want
to amend otp library (governed by Erlang PL, amendment required to be
governed by Erlang PL) with calling GPL code - that is a problem because
of two licenses copyleft clash, unless you manage to do so making GPL
code optional and not distributed within your amended otp code.

-- 
Volodymyr Kyrychenko



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