Re: GPL V2 and GPLv3

[Michael Poole <mdpoole@troilus.org>]

Peter S Galbraith writes:

>> An .el source code file doing a 'require' or 'load' does not make the
>> source 
>> code a derived work. It's like an "#include <...>" statement in C source 
>> code. Compiling it might make a derived work, but it's not a derived work 
>> just because it mentions the name of a file it's asking a compiler to 
>> include when executed. 
>> 
>> Anyway, you could possibly argue either way if the .elc file is make a 
>> derived work by "linking" to emacs. But the .el file by itself is 
>> unquestionably not a derived work and could be under any license at all.
>
> Wow.  I don't think I could disagree more. Loading the library
> presumably means we are going to invoke some of its code.  So you are
> saying that an interpreter under any non-free license can use any GPL'ed
> library?

That is not at all what he said.  The test for whether work A is a
derivative work of work B does not look at programmatic linking or the
mechanism for doing that.

If program A depends on some interface, and program B is only one of
several programs that implement that interface, A probably is not a
derivative work of B.

In this case, there are older emacsen -- distributed under licenses
other than the GPLv3 -- that provide the interfaces needed by most or
all of the elisp in question.  It is clearly absurd to say that a work
written a year (or five years) ago depends on a GPLv3-licensed version
of emacs; there was no such thing when the older work was written.

Michael Poole