Re: Interpreted octave code and GPL

[Francesco Potortì]

>>> On 19/08/2012 17:15, Carnë Draug wrote:
>>> Ok, but lets put it another way, lets say I write an function in
>>> interpreted code and release it under the GPL. Can this then be taken by
>>> others and used in a non-free program?
>> You write a GPL function.  I have a non-free program (or more generally,
>> a GPL-incompatible program) that needs your function.  My program can
>> happily and legitimally use your function.  However, if I distribute my
>> program, I must do it under the terms of the GPL.

Francesco Potortì:
>> This is a generic answer to a generic question.  If you want more detail,
>> you must provide more.
>>
>>> If not, then why can I call the Octave core m-files in a non-free
>>> program, which is what is implied by the wiki? Surely they're exactly
>>> the same, but just have a different origin.
>> I'd say Octave is an environment, and the core m-files are part of the
>> environment.  You install the environment in your box.  I give you the
>> program.  If, on the other hand, I distribute my program together with
>> the environment, then I must do so under the GPL.  I think this is the
>> rationale behind
>> http://wiki.octave.org/FAQ#If_I_write_code_using_Octave_do_I_have_to_release_it_under_the_GPL.3F
>>
>> Am I right?
>>
>
>Ok, I think I see what you're getting at. I effectively can use the name 
>or function calling syntax of any function in a non-free program, but I 
>could not distribute the actual code implementing that function with my 
>program if it is not GPL?

In fact, I was speaking about the Octave core functions only.

>But on the FSF FAQ it states that
>
>"A system incorporating a GPL-covered program is an extended version of 
>that program. The GPL says that any extended version of the program must 
>be released under the GPL if it is released at all."
>
>it goes on to say
>
>"However, in many cases you can distribute the GPL-covered software 
>alongside your proprietary system. To do this validly, you must make 
>sure that the free and non-free programs communicate at arms length, 
>that they are not combined in a way that would make them effectively a 
>single program."

If you go on reading, this means that, if you do that, you should make
it clear that Octave si a program and an environment per se, and your
program is something distrinct that uses Octave.

>I don't really see how having a call to a GPL m-file function in my 
>program could be considered "at arm's length".

Your program "uses" Octave, the way a shell script uses Bash.

>Is it because we take Octave and it's core m-files to be a "Standard 
>Interface" as defined in the GPL?

I'd say yes.

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