License compatibility of MS-PL and MS-CL (Was: (RE: Groklaw's OSI item (was: When will CPAL actually be _used_?))

Matthew Flaschen matthew.flaschen at
Wed Aug 29 20:13:40 UTC 2007

Chris Travers wrote:
> Ok, so if we take my second hypothetical and state that you must
> identify code which you are only using by permission and don't have
> copyright claim to (itself), then how is this different?

Even though you don't have copyright claim for this tweaked BSD code,
nothing in "tweaked BSD" prevents you from sublicensing under the GPL.

  In effect, you are just preserving the license on those chunks of code
since you are
> announcing that they are copyrighted elsewhere and used with permission
> which has been granted to the public.

You are making it very clear which parts are tweaked BSD, but that
doesn't mean tweaked BSD code can't *also* be GPL.

> In short you are saying, "I don't own this code and cannot control what
> you do to it.  The author has given a public license to the code.  See
> the top of the file for details."

It might be better if you reply with a full license, since BSD is short
and you've made so many changes.

> This is, of course, assuming that the MS-PL does not lay claim to any
> derivative or collected works and that "the software" means "the
> accompanying software."

But this includes "the accompanying software" when it is part of a
derivative work.

> I am not sure.  In this example, perhaps with some slight rewording, I
> have effectively prevented sublicensing of the code itself

*No*, you haven't done so effectively.  This has to be done clearly,
either by saying something like, "Sublicensing is not allowed" (GPLv3)
or "you may do so only under this license" (MS-PL)

> because I ask you to attribute copyrights to my code to me and advertise to the
> developer the public license I have granted.

All you're requiring is that I be clear about which code is under your
license.  You're not requiring that I can't also sublicense this code.

  I can do this without
> including "only" in the license, and I can do this using *only*
> attribution requirements and legal notices.
> The reason is that my specific code is *only* under licenses I grant it
> anyway.

But you can give permission to sublicense.

> The reason is that my code copyrights can't be enforced by those who
> alter it anyway.

Correct.  I can't enforce copyright on your code; I *can* sublicense it,
and enforce copyright on my own code in the derivative work.

> 2)  Is this functionally different than the MS-PL (assuming that "the
> software" only applies to the source code of "the accompanying software"
> and not to copyrighted elements of that code present after modification).

Copyright elements of /which/ code present after modification?

Matt Flaschen

More information about the License-discuss mailing list