Re: LGPL v3 compatibilty
Anthony W. Youngman wrote:
If your GPLv2 program links to an LGPLv3 library, then you don't need to
give a monkeys.
The whole point behind LGPL is that the LGPL library must be
independently distributable, and independently upgradeable. If your
program is GPL (any version), then it is compatible with any LGPL
library (any version).
I don't think that's correct.
Clearly, as you say, there's no problem from the LGPL library's point of
view. However, the GPL2'd program says that any code that is part of the
program needs to be under the GPL2. Now there are various licenses held
to be compatible with the GPL2, in that their provisions are a subset of
the GPL2s - such as the BSD licence family. So libraries under those are
no problem. And the LGPLv2 can be converted to the GPLv2 via a clause in
it, so LGPLv2 libraries are OK too. But if, for example, your library is
MPLed, you are stuck. There's no way to make MPLed code compatible with
GPLv2. And the same is true of LGPLv3, which can also not be made
compatible with the GPLv2 (because it has extra restrictions over and
above those in GPLv2, and GPLv2 forbids extra restrictions).
Of course, if you own the copyright on the GPLv2 program, you can add a
license exception for linking with the LGPLv3 library.