Re: A plea for dynamically loadable extension modules

[Mario Lang <mlang@delysid.org>]

Jason Rumney <jasonr@gnu.org> writes:

> Mario Lang wrote:
>> I do not fully understand this.  If the use of
>> non-free code in Emacs is explicitly forbidden, what is the problem then?
>> If someone would use a dynamic loader extention to integrate
>> commercial code with Emacs, he would just violate the license.
>
> Allowing dynamic linking makes it easier for the end-user to violate
> the license, perhaps unwittingly, while the distributer of the linked
> module might technically escape from any wrongdoing since they are not
> doing the linking.
>
> But I think the specific change that the objections were raised about
> was a general dynamic linking mechanism that would allow Emacs to link
> to any library. There is another type of dynamic linking, where
> linked modules would need to conform to an Emacs-specific interface.

I was not refering to a generic FFI, I was refering to
the second case you mentioned, an extention which required
linked modules to be specially written for Emacs.

Quoting Dave's mail to g.e.sources from 10 Apr 2002 23:22:27 +0100:

"This patch for Emacs 21.1 basically extends `load' to allow loading
compiled C modules and provides a script to build them."

It seems clear to me according to the attached REAMDE that
this extention does not provide a generic FFI.

So I think the point you raised above is not valid here.

> Then only Emacs-specific modules could be linked to Emacs. It would then
> be much easier to tell developers of non-Free modules that linked to
> Emacs to make their code Free, since they could not claim that their
> module was exempt from the GPL because it was designed to link with 'Y',
> not with Emacs.

Exactly.  The patch from Dave satisfies the mentioned
properties AFAICS.

-- 
CYa,
  Mario | Debian Developer <URL:http://debian.org/>
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