[ANN] gmpxx_mkII.h: Yet another GMP C++ Wrapper for High-Precision Calculations

[Hans Åberg]

> On 11 Oct 2024, at 12:33, Vincent Lefevre <vincent at vinc17.net> wrote:
> 
> On 2024-10-11 12:11:14 +0200, Torbjorn Granlund wrote:
>> GMP is made available under the GPL.  Anything that is linked to GMP,
>> even if it is through some "wrapper", needs to adhere to the freedoms
>> and restrictions which GPL mandated.
>> 
>> Even if you put many libraries or "wrappers" in a chain of dependencies,
>> if GMP (or any other library under any other license) is pulled in, then
>> its license is relevant to the resulting binary.
> 
> This is true for any software that uses GMP. Currently, MPFR doesn't
> warn about that. But if I understand you, we should. This currently
> doesn't have any consequence since GMP has a license compatible with
> MPFR's, but imagine that one day GMP switches to LGPLv4+ (if it comes
> out). Then this would affect MPFR (if still under LGPLv3+).

This is only the case if the binary is redistributed and it contains copyrighted code, which is not case if it is a package that is compiled locally, or if it links dynamically after distribution.

Bison uses LGPL for the parser it generates, so that it can be compiled and the binary redistributed.

This page GMP uses LGPLv3, but does not say to what it applies:
https://en.wikipedia.org/wiki/GNU_Multiple_Precision_Arithmetic_Library