A dual license system for code libraries?

Paul Boddie paul at boddie.org.uk
Sat Feb 25 13:44:26 UTC 2017

On Saturday 25. February 2017 09.54.39 Agner Fog wrote:
> Hi, I have a problem with several open source projects. Neither GPL nor
> LGPL license seems to be appropriate.
> One such project is my C++ vector class library
> (http://agner.org/optimize/#vectorclass )
> Right now, I am using a dual license system. The library is published
> under GPL, following the advice at
> https://www.gnu.org/licenses/why-not-lgpl.html
> However, there is a significant demand for using this library in
> commercial closed-source code. Therefore, I am selling commercial
> licenses to anybody who want to use the library in commercial code.

Proprietary code, not commercial code. (Yes, I know you also wrote "commercial 
closed-source code", but commercial code does not have to be proprietary, nor 
is proprietary code necessarily commercial.)

> Now, there is a problem with unifying the copyright. I want to put this
> code on github and make it a collective project. But then I can no
> longer be the only copyright owner.

Well, what you're asking about here is how you can have an organisation with 
ownership or control over the copyright, which may have something to do with 
things like copyright assignments or contributor licensing agreements that can 
be topics affecting Free Software projects, but then...

> It is not fair that others should contribute to the project for free while I
> make profit on selling licenses. We would have to set up an organization to
> own the copyright and sell licenses. But the administration cost of running
> such an organization would probably eat up all the income. And open source
> programmers prefer to spend their time on programming, not on administration
> of an organization.

...this is almost like asking for business advice: how ownership in a company 
is structured, how contributions translate to "investments" in the value of 
the company. Now, there are organisations that have attempted to figure out 
the latter, but it is very controversial to try and put a value on what 
someone has contributed to a project, and it seems to me that most people 
steer clear of the matter and leave it somewhat open.


> More importantly, people would have little motivation to contribute to
> an open source library when their work only goes to somebody else's
> profit.

Which is why copyright assignments and unfavourable contributor licensing 
agreements involving companies deter contributions to the projects concerned.

> The motivation would be higher if the effort could somehow contribute to the
> general goal of supporting free software. That's why I prefer the dual
> license solution. The only problem is who should own the copyright and sell
> commercial licenses?
> I have asked the FSF, but they are not willing to sell licenses, and
> frankly they are quite difficult to communicate with. That's why I am
> now taking the discussion to FSFE. Is there any other suitable
> non-profit organization who could be the copyright owner and sell licenses?

You have to remember that Free Software is all about end-user empowerment. If 
a user gets a binary that gives them none of the privileges of Free Software 
then it doesn't matter in practice what went into making that software: they 
are being denied the ability to participate in controlling what that software 
- the actual thing they obtained, not part of it - actually is or does.

Where a scheme advocates putting proprietary software in front of users, it is 
not going to get the support of the FSF, because even the LGPL is effectively 
a barely palatable concession to the idea that Free Software might be used in 
proprietary software under certain circumstances. I don't think you should 
expect the FSFE to take a different position.

I think that more attention should be given to funding mechanisms for Free 
Software. However, it seems to me that you are effectively asking the FSF for 
business advice, which is something people usually have to pay for. That would 
also explain why they might not have been very motivated to communicate with 
you: giving such advice to businesses dealing in proprietary software is not 
exactly the mission of the FSF.

For what it's worth, you could look at what existing businesses have done in 
this area already. There have been several companies that have offered dual-
licensing schemes, and some of them may even have offered something resembling 
what you are trying to achieve.


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