GMP license problem, anyone?

Joerg Arndt arndt at
Thu May 29 13:50:20 CEST 2008

[forgot to copy the list]

* Bill Hart <goodwillhart at> [May 29. 2008 21:39]:
> On 29/05/2008, Vincent Lefevre <vincent at> wrote:
> > On 2008-05-29 07:53:45 +0100, Bill Hart wrote:
> >  > Firstly FLINT actually uses extensive portions of GMP in its integer
> >  > library. It doesn't just link against GMP, though it does that also.
> >  > If I want to keep doing that, I am limited to what was available in
> >  > GMP 4.2.1 if I want my project to be part of SAGE, which is at least
> >  > philosophically committed to GPL v2+. SAGE doesn't just link against
> >  > FLINT, it includes it, the same as it includes GMP.
> >
> >
> > If I understand correctly, you could still release some parts of the
> >  project under (L)GPLv2+ and other parts (what is related to GMP 4.2.2)
> >  under LGPLv3+. When you build and link the whole, it will be under
> >  GPLv3+, but is this a problem? Why?
> Probably you meant to quote the other paragraph, for which this may
> appear like it is a solution.
> But there are lots of problems with it. It doesn't work for SAGE,
> which aims to have a fully v2+ distribution which includes the whole
> of FLINT.
> It doesn't work for any other project committed to v2+ which may wish
> to include all or even a large portion of FLINT.
> The next generation FLINT will have an integer library for which each
> function is basically half from GMP and half my own code. But what is
> the use of half a function!? Also it's annoying to document license
> changes mid function. It's even worse when you consider that some
> functions in GMP will be v2+ and some v3+.
> But most important of all, it doesn't help me in that I don't want to
> promote the use of version 3+ licences, since the problem just
> proliferates. I want whatever I release, whether a function, a module
> or an entire project to be fully compatible with GPL v2+.
> Bill.

>From the compatibility matrix at
you seem to only get problems with code that is under ver.2 _only_
(i.e. without the "or later").  How much code under ver.2-only are
you looking at?

Ver.3 is there for a reason so switching to it is IMHO the right thing
to do.

cheers,  jj

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