[cc-community] Strengthening the CC-BY-SA copyleft with respect to code

Rob Myers rob at robmyers.org
Wed Dec 21 17:46:58 EST 2011

On 21/12/11 20:01, Maciej Pendolski wrote:
> On Wed, Dec 21, 2011 at 8:50 PM, Rob Myers <rob at robmyers.org> wrote:
>> To the extent that the script layer has "carnal knowledge" of the
>> internal data structures of the game engine, the entire game engine
>> would need to be GPL anyway.
> GPL allows a System (here an engine) and its System Libraries (API
> calls available for scripts) to be under any licence. Otherwise you
> could not run open source software on Windows or compile it with
> MSVC++.

The "System Libraries" exception is a specific and well-defined term
introduced by GPL3:


"The “System Libraries” of an executable work include anything, other
than the work as a whole, that (a) is included in the normal form of
packaging a Major Component, but which is not part of that Major
Component, and (b) serves only to enable use of the work with that Major
Component, or to implement a Standard Interface for which an
implementation is available to the public in source code form. A “Major
Component”, in this context, means a major essential component (kernel,
window system, and so on) of the specific operating system (if any) on
which the executable work runs, or a compiler used to produce the work,
or an object code interpreter used to run it."

A game engine would neither be the operating system nor an object code
interpreter, it would be part of the work as a whole. The scripting
engine of a game engine would not firewall the game engine (especially
if it exposes internal data structures or functions). The "system" is
clearly the operating system, not the program.

IMO, I Am Not A Lawyer, etc.

- Rob.

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