Re: proposed FAQ entries about licensing

[Svante Signell]

On Wed, 2009-03-25 at 10:30 -0400, John W. Eaton wrote:
> On 25-Mar-2009, Svante Signell wrote:
> 
> | What about replacing a .m file with a C/C++ function for execution speed
> | purposes? Does this fall in the same category as an .m-file, i.e. no
> | requirements on the license?
> 
> The reason for writing the plug-in (.oct or MEX) doesn't change the
> licensing requirements.  What is important is that you are linking
> with Octave, so must follow the terms of the GPL.  Perhaps we should
> also explain more clearly in the FAQ answer why a MEX file can be
> licensed any way you choose, but the same is not true for .oct files.
> We hint at it by saying that a .oct file necessarily links with Octave
> internals, thus creating a derivative work, but it might not be clear
> why a MEX file does not have the same restriction.
> 
> For MEX files, the situation is different becuase we don't think that
> a MEX file creates a derivative work, because the interface is not
> specific to Octave.  Indeed, it is possible (even relatively easy) to
> write and compile MEX files that do not even include any header files
> or link to any Octave- or Matlab-specific libraries and that can be
> loaded and run by either program.  You don't even need Matlab or
> Octave on a computer in order to build a functioning MEX files (but
> you need one or the other of those programs to use the resulting MEX
> file function).  Because of this, the FSF doesn't think that MEX files
> should fall under the same requirements of .oct files, provided that
> you meet the requirements that are stated in the FAQ answer that I
> posted.

Another question about Octave. A method to (weakly?) protect some .m
files they can be encrypted creating .p-files in MatLab. Is it possible
to create .p-files in Octave, or if created in MatLab can they be run in
Octave. (The answer to this is probably negative but I'll ask anyway).

The background to this question is that we have developed a large
package based solely on .m-files. It could be viewed as a toolbox. We
have written it so it can be executed in both MatLab and Octave
environments for PC and *nix to make it available in both environments.

In order to commercialize it we will hand out most of the .m-files as
GPL-ed code, but want to keep some essential .m-files protected. Of
course this is mainly to be able to be able to sell the package and
subsequently develop it further without risk of theft or cloning before
we are established with our product.

Thanks,
Svante