Re: What license to use for Emacs libraries?

[Marcin Borkowski <mbork@mbork.pl>]

On 2015-08-18, at 23:53, Stefan Monnier <monnier@iro.umontreal.ca> wrote:

>> Does that mean that releasing Emacs libraries under GPLv2 is illegal?
>
> Pretty much, yes.  Since they necessarily link to Emacs's own code which
> is GPLv3+, you have to use a license that's compatible with GPLv3+.
>
> Note that GPLv2+ is one such compatible license (as opposed to GPLv2).
>

OK, thanks for the clarification.  As I said a moment ago, the
distinction between GPLvn and GPLvn+ escaped me.  That explains a lot.
(Still, all this licensing stuff feels much like craziness to me.)

>> I did a cursory check, and it seems that all libraries built-in in my
>> Emacs are GPLv3, but some other are not:
>
> No, they're GPLv3+ (most licenses out there implicitly say "this version
> or any later version of it", whereas the GPL is more strict and you
> have to explicitly say "GPLv2 or later").
>
>> for instance, my copy of Icicles has GPLv2, and some code on EmacsWiki
>> has GPLv2.
>
> If it's stritcly "GPLv2 and no later" then it's probably an error.

No, it's "GPLv2 or later" (at least with Icicles), so everything is fine
there.  Still, it is kind of funny: it is not enough to look into the
file named LICENSE to learn what license the code is under.

>> Does that mean that GitHub is a part of a sinister software-patent
>> conspiracy or something?
>
> That wouldn't be a surprise, now, would it?

Now that Phillip warned me (implicitly) about GitHub police visiting me
at 5am with handcuffs I'm afraid to say anything more on this topic. ;-)

>         Stefan

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University