The GPL Is a License, not a Contract [LWN.net]

The GPL Is a License, not a Contract

Posted Dec 4, 2003 6:15 UTC (Thu) by proski (subscriber, #104)
Parent article: The GPL Is a License, not a Contract

The problem is that GPL is sometimes (mis)understood as a contract by the software authors. An example of such software is XFoil. The webage says:

By downloading the software you agree to abide by the GPL conditions.
The most important conditions are:
* Any port of this XFOIL software to another platform must be made public under the GNU GPL
* Any port of this XFOIL software to another platform must be provided with the source code
* Any port of this XFOIL software must retain the "XFOIL x.xx" name and the original copyright

So what happens if I download XFoil, port it to another OS (say, Mac OS) and use it only for my projects? Can the author go after me and demand that I release my changes in the code? GPL (when understood as a licence) doesn't require it. In fact, it has no effect on me as long as I don't distribute the software.

But on the other hand, the author clearly considers GPL to be a contract that binds the users from the moment they download the software. The judge could be sympathetic to the argument that the interpretation of GPL as a contract was posted by the software author, and thus GPL should be treated as a contract. This could be a disaster for a large company doing aircraft designs if its lawyers trusted the words of Professor Moglen without looking at the homepage of the project.

Similar problems can happen with other software that can be significantly reworked without being distributed, e.g. web applications and server software in general.

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The GPL Is a License, not a Contract

Posted Dec 4, 2003 9:01 UTC (Thu) by piman (subscriber, #8957) [Link]

There are a number of software authors that use the GPL without understanding it, or copyright law. The XFoil author seems to be one of these. In fact, all 3 of those are conditions above and beyond what the GPL requires; the result is that XFoil is licensed inconsistently, and probably can't be distributed and modified at all (except by the original author).

So, Prof. Moglen is correct that the GPL can never be a contract; the problem is that XFoil isn't under the GPL, but some inconsistent GPL+otherstuff license.

The GPL Is a License, not a Contract - XFoil

Posted Dec 4, 2003 17:51 UTC (Thu) by Ross (subscriber, #4065) [Link]

Items 1 and 3 don't appear to be correct interpretations of the GPL.
As such, wouldn't they be extra conditions and therefore incompatible
with the GPL?

Oops

Posted Dec 4, 2003 17:53 UTC (Thu) by Ross (subscriber, #4065) [Link]

I didn't notice the other response to your post. They are correct,
items 2 is also overly broad because a port could also be shipped
with a written offer for the source code.