[Haskell-cafe] gmp license == no commercial/closed source haskell software ??

Don Stewart dons at galois.com
Wed Dec 3 09:36:57 EST 2008

> I've just discovered the GMP license problem. (see 
> http://hackage.haskell.org/trac/ghc/wiki/ReplacingGMPNotes)
> From my understanding, the gmp is GPL, GHC statically links it on windows.
> As a consequence, any program compiled using GHC must be distributed 
> under a GPL compatible license.

GMP is *LGPL*.
> In the threads I've read, some workarounds are proposed on linux and 
> OsX, but I didn't see anything on windows.
> Is the situation still the same  ?
> Does anybody know a work-around to make a closed-source programm in 
> haskell without violating the GPL ?

It is LGPL, which is a very important distinction. It just must be
possible to replace the libgmp component with another that has been
modified - you can't actively prevent people replacing the libgmp

Supporting this is trivial with a dynamically linked / DLL libgmp. With
a statically linked  one, it is also possible, since the API calls to
libgmp are specified.

This shouldn't prevent commercial use -- lots of other companies have
decided this is OK. You just need to be aware of it.

-- Don

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