GMP license problem, anyone?

Bill Hart goodwillhart at
Thu May 29 08:53:45 CEST 2008

Sorry, this wasn't at all clear. Let me rephrase. I just now realised
the problem with what I 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.

The issue is more complicated than that, as I indicate. I shouldn't
really speak on behalf of SAGE itself, since I know less about it than
FLINT, but as I indicate, some of the projects in SAGE are v2+. To
support their development, I as a developer of code to be included in
SAGE, want my code to be compatible with their licenses. I know other
SAGE developers want to do the same. If I did include code from GMP
v4.2.2 or above in FLINT, then I would be forced to use GPL v3 or v3+
and this would mean others who wanted to stick with v2+ could not then
include my code. So I won't do that.

The other way around, there is no problem. Someone using GPL v3 on
their project can use my code.

Sorry I didn't make this very clear in the first instance. Also I
wasn't clear until tonight that there wasn't any v2 only code in SAGE,
but there isn't any more apparently.


On 29/05/2008, Patrick Pelissier <patrick.pelissier at> wrote:
> > Some months ago now, at a conference, the license issue was brought
>  > up. Because SAGE makes use of numerous packages, some of which are GPL
>  > v2+ it cannot change to GPL v3+ and numerous members of the SAGE
>  > community appear to be against doing that on principal anyway. I have
>  > to admit I am also such a person. FLINT will always remain GPL v2+ and
>  > so cannot ever use future versions of GMP if they remain LGLP v3+.
>  > This leaves me with few options.
> Hi,
>   I don't understand the issue.
>   If FLINT if GPLv2+, it can link either with GMP LGPL v2+ or with GMP LGPL v3+.
>   See the compatibility matrix:
>   The problem is only for "GPLv2 only" projects.
>  --
>   Sincerely,
>   Patrick Pélissier

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