GMP license problem, anyone?

Patrick Pelissier patrick.pelissier at
Sat May 31 10:58:47 CEST 2008


 I still don't understand why you don't link with GMP 4.2.2 while
keeping in FLINT the code you get from GMP 4.2.1.
 It will be a lot simpler to maintain a specific code for FLINT based
on GMP 4.2.1 (and more efficient) rather than maintaining a fork of
 And it seems to me that's all you need (FLINT and SAGE will remain in GPL V2+)

 Please clarify if I haven't understood all the issues.

  Patrick Pélissier

On Thu, May 29, 2008 at 8:53 AM, Bill Hart <goodwillhart at> wrote:
> 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.
> Bill.
> 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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