Re: GPL, LGPL, and copyleft

[Jordi Gutiérrez Hermoso]

2012/3/29 Daniel J Sebald <address@hidden>:
> On 03/29/2012 03:36 PM, Jordi Gutiérrez Hermoso wrote:
>> It is some sort recurrent fantasy that the precise way in which things
>> are combined matters.
[snip]
> Please quote what lines you are referring to.

The last lines read,

    But if the semantics of the communication are intimate enough,
    exchanging complex internal data structures, that too could be a
    basis to consider the two parts as combined into a larger program.

This seems to be precisely what GUI Octave is doing, "exchanging
complex internal data structures".

> This whole licensing thing with version 1, 2, 3 and the L appended
> to GPL has a sort of mission creep aspect to it.  Its playing a game
> which in itself sort of defeats the spirit of free software. Should
> the license be changed simply because the application becomes
> popular or not-so-popular?

The license changes because people find new way to get around it, ways
that weren't envisioned when it was first created, such as DRM and
Tivoisation (making the hardware check the software's hash and refuse
to run if the hash has changed, effectively forbidding in hardware the
ability to run modified software).

> So, does GUI Octave alter any source code?

This isn't relevant. Copyleft is hereditary, based on the concept of
derived work from copyright. The GPL has successfully been proven in
court that certain uses of it are derived work, thus acceptable for
copyleft, but not, as far as I know, has the FSF's linking theory been
tested in court. The FSF has yet to make an incorrect prediction of
how the GPL will hold up in court, however, and they've been proven
correct numerous times already.

> The MEX interface?  Is that the method by which C files can be
> compiled and interfaced to Matlab?  GUI Octave uses a MEX interface?

No, this isn't about GUI Octave. It's a possible reason why Octave's
library is GPLed and not LGPLed. The GNU Scientific Library is another
GPL'ed numerical library. So is FFTW, and they sell GPL exceptions. I
find that fair. Everyone who makes derivative work from FFTW pays,
either with money or with code.

- Jordi G. H.