[Balug-talk] GPL vs. LGPL

[Bill Moseley]

Can anyone here explain in plain language what the differences are for LGPL vs. GPL, with 
regard to use in or with proprietary code?  Or perhaps point me to somewhere else to 
ask.

Here's the issue.  Swish-e, an indexer and search engine, is currently GPL'd.  Some have
wanted to use Swish-e in their own products but were scared off by the GPL.  So it's been
recommended to use LGPL instead.

I have read the licenses and also have read the RMS page "Why you shouldn't use the Library
GPL" and quite a bit of other pages that Google has fetched.  Others have read the same
pages and licenses and now we have two groups, one that thinks that if someone uses GPL
swish-e in any way in their proprietary product that then their code may not need to be
GPL'd but it must be Open Source.  Others do not see that requirement.  So that's really the
main point I'm trying to clear up -- how can makers of proprietary software use Swish-e.

Some also favor LGPL thinking it's less restrictive and thus more people will use the 
software (which is what they desire).  If I understand correctly, I see LGPL is a way for 
someone to take swish-e as a base and create a new proprietary program.  I don't really see 
that risk for Swish-e, but I could see a situation where someone could then force 
users to buy a product as the only upgrade path and no longer have access to source.

I realize this is a more than a legal question, and I'm not trying to start a long 
discussion, but rather just to clear it up in my own mind what people can do with the 
software.  And excuse my ignorance about such matters.

My point of view is I wouldn't want someone taking Swish-e and adding it into their
proprietary package and calling it their own.  I don't mind someone selling their own
closed-source software and using swish-e, say, for indexing and searching their HTML
documentation, as long as they tell their customers they are doing so, and that any bug
fixes or enhancements are given back to the swish-e community of users.

I find LGPL confusing (of course I do else I wouldn't be asking).  Even though it's called 
"lesser" it still seems about libraries.  Swish-e is a binary program, but most of the code 
is built into a library and just a few small files are linked with it to build the binary.  
So I have a real hard time seeing any difference between someone using libswish-e vs. 
swish-e the binary -- they are really the same thing.

And then...

Section 5 of the LGPL says:

---------
5. A program that contains no derivative of any portion of the Library, but is designed to
work with the Library by being compiled or linked with it, is called a "work that uses the
Library". Such a work, in isolation, is not a derivative work of the Library, and therefore
falls outside the scope of this License.

However, linking a "work that uses the Library" with the Library creates an executable that
is a derivative of the Library (because it contains portions of the Library), rather than a
"work that uses the library". The executable is therefore covered by this License. Section 6
states terms for distribution of such executables.
---------

Is that clear to everyone else but me???


Thanks,




-- 
Bill Moseley
moseley at hank.org