How To Break The GPL
Andrew J Bromage
ajb at buzzword.cc.monash.edu.au
Sat Mar 4 01:26:38 UTC 2000
On Fri, Mar 03, 2000 at 10:45:47AM -0500, John Cowan wrote:
> This is offered in the spirit of "How To Make Atomic Bombs", and does
> *not* mean that the author approves of the conduct described herein.
> Now who has violated Trent's copyright? Not Alice: she did not modify or
> distribute Trent's work.
Alice wrote and distributed what is, in the opinion of RMS, a derived
work of Trent's work and thus her work is covered by the GPL.
In the discussion which follows, I'll restrict myself to the case of
a non-GPL'd work usig a GPL'd library.
This is probably the most legally controversial part of the GPL. It's
difficult to say whether or not a program which uses a library is a
derived work of that library. If I were a judge (and IANAL so this is
unlikely to say the least), I would probably decide on a case-by-case
If, for example, there exist non-GPL'd implementations with an identical
interface and equivalent functionality, I would have to rule that it is
_not_ in the spirit of "derived work" to class the program as a derived
Let's make it a little more specific and ask yourself "is Alice's program
a derived work of Trent's code"?
Alice writes a graphics program (perhaps a game, for example)
which is developed using Trent's GPL'd implementation of OpenGL.
In this case, there are many proprietary implementations of
OpenGL available. When Alice sends her sh/make/English
instructions to incorporate Trent's code include an instruction
_not_ to download Trent's code if there is already an
implementation on Bob's machine.
More information about the License-discuss