[Haskell-cafe] short licensing question

Ketil Malde ketil at malde.org
Tue Jan 12 15:21:49 EST 2010

Sebastian Fischer <sebf at informatik.uni-kiel.de> writes:

> I wonder whether the following statements are valid:

You want my layman's opinion?

> When I write a program that uses an LGPL library, I am allowed to
> distribute the *sources* of my program under a permissive (non- 
> copyleft) license like BSD3.

Yes.  I don't think using an API counts as deriving a work - the
alternative would be to difficult and have too many dire consequences
that would go against current practice (any program on, say, Linux,
would be a derived work of the kernel - and probably vice versa).

> I am not allowed to distribute my program in *binary* form under a
> permissive license (even if I release the sources too).

This would be a shame, since this is the whole raison d'être for LGPL.
The point of LGPL is to ensure that any recipients of your program is
able, should they so desire, to replace the LGPL library with a modified

> Am I allowed to distribute the sources under BSD3 and the binary under

I'm not sure this makes a lot of sense.  But clearly, you can't
redistribute somebodys LGPL library as BSD3, wether in binary or source
form.  You may of course distribute your bits as BSD3, which anybody
could redistribute as LGPL or GPL.

The point of LGPL is to be somewhat less "viral" than the GPL in that
you may link LGPL code with otherwise licensed code and even
proprietary, binary only code.¹  E.g. readline, which was explicitly GPL
to "force" more software to adopt that license, while LGPL would
"encourage" keeping different license.  

¹ Whether the current license achieves this is a different matter, and
LGPL is clearly either too strict or too lenient for most people.  I
like it, though. 

If I haven't seen further, it is by standing in the footprints of giants

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