[Haskell-cafe] Re: base-4 + gtk2hs-0.10.0 licensing

Peter Hercek phercek at gmail.com
Wed Feb 25 17:38:41 EST 2009

Peter Verswyvelen wrote:
> On Wed, Feb 25, 2009 at 11:02 PM, Peter Hercek <phercek at gmail.com> wrote:
>> * An LGPL library will force commercial users to release their source code
>> only to the users of their program (which already bought it) and only for
>> the purpose of recompiling with a newer version of the LGPL library.
> Does this also mean one can't make closed source but *free* software
> that uses LGPL libs? Since all users can then potentially request the
> source code? E.g. suppose Google would have used LGPL libraries to
> implement parts of their search engine...
I think so. If you acknowledge them as legitimate users and you 
distribute the free program then you must allow them to upgrade the LGPL 
library. With Haskell this may mean releasing the source code. I'm vary 
about this part though. *.o and *.hi may be enough since:
* GHC is not LGPL but some kind of BSD
* only the gmp and gtk2hs are LGPL
* so you do not need to make sure ghc can be upgraded
* you need to make sure gmp can be upgraded and gtk2hs can be upgraded 
but forcing users on the same version of ghc
* requirement to allow upgrade is there only while the LGPL library does 
not change interface

The above should allow to distribute only *.o and *.hi files. If user 
wants to to upgrade GMP or GTK2HS they can do it and recompile with the 
old version of GHC (the one for which you provided *.o and *.hi files.

So my opinion (IAMNAL):
1) source code under very limiting commercial license (just to allow 
recompile with a newer LGPL lib and nothing else) is OK
2) it is probable that only the *.o, *.hi files and a linking script are 
OK too

As for as Google: That is a different case. The GPL/LGPL limitations 
kick in *only* when you redistribute your program. Goolge is not 
redistributing their search engine! They only provide you a service over 
internet! That is very different.


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