Dynamic Linking and GPLv3

(aka. How GPLv3 affects the relationship between Proprietary and Free Software)

From the GPLv3 rationale[1]:

We wish to make completely clear that a licensee cannot avoid complying with the requirements of the GPL by dynamically linking an add-on component to the original version of a program.

What does this mean? Does it mean that proprietary software can no longer depend upon copy-lefted Free Software?

One of the proudest example of Open-Source software (and yes, I do mean Open-source, not Free, software) that I have frequently cited to my beer budies[2] is the use of libvorbis in various commercially succesful (and critically acclaimed) PC games such as the various Unreal Tournaments, Far Cry, etc. It shows that the (Free/) Open-source Software Development Philosophy does produce Cool Softwareâ„¢[3].

I understand that this provision would prevent a rouge software developer from creating a proprietary DLL/library, linking it to GPL’ed software, and declaring the whole a package restricted to licensed distribution (aka. non-free). But it forces implementers such as the W3C (in libtidy) and the Ogg foundation (with libvorbis) to license their software under non-free licenses. At least the way I understand software freedom.

And it seems to run counter to a principle exemplified by the section’s last paragraph:

The final paragraph of section 1 revises the exception to the source code distribution requirement in GPLv2 that we have sometimes called the system library exception. This exception has been read to prohibit certain distribution arrangements that we consider reasonable and have not sought to prevent, such as distribution of gcc linked with a non-free C library that is included as part of a larger non-free system. This is not to say that such non-free libraries are legitimate; rather, preventing free software from linking with these libraries would hurt free software more than it would hurt proprietary software.

(Strong emphasis mine). So which is it? Can proprietary software link to free software, or can’t it?

[1] From GPLv3 Rationale Document, Section 2.2 1. Source Code [http://gplv3.fsf.org/rationale], as accesed on Sunday, January 29, 2006 12:29:29 AM UTC+7:00. The rationale may have changed since then, since at this time GPLv3 is still undergoing a review process. Check the Rationale page to be sure wether my comments are still relevant or not.

[2] You know who you are. Okay so I don’t often drink beer that often with you guys, and yes I do wish that I could spend New Year’s Eves getting drunk with y’all but you know my family… :p

[3] in adition to (rather than as opposed to) technically superior, industrial-strength, mission-critical, bullet-proof secure, boring-to-adolescent-gamers software.

Final note: I’d just like to add that in no way do I consider myself a knowledgeable hacker or lawyer. As this website is a blog, this article is a rant. I kindly request you consider this while you flame me :0)