GMP license problem, anyone?

Paul Zimmermann Paul.Zimmermann at
Wed May 28 19:20:57 CEST 2008

       Dear Jan,

> Could you please summarise or point to (short) documentation what that
> means for a project that is otherwise LGPL 2 (and some compatible OS
> licenses)?

a "compatiblity matrix" between the (L)GPL licenses is available at:

In summary:

Copying code which is in LGPL v3 (e.g., code from GMP 4.2.2):
* if your project is in LGPL v2.1 only, you cannot at all
* if your project is in LGPL v2.1 or later, you cannot either (unless you
  decide to switch your project to LGPL v3, but then you cannot include any
  more code that is in LGPL v2.1 only)

Using a library under LGPL v3 (e.g., linking dynamically with GMP):
* this is always ok, except if your project is in GPLv2 only

What is still unclear to me is when you link statically with GMP 4.2.2.
If your project is under LGPL v2.1 or later, if one consider that linking
statically corresponds to copying code, then it automatically falls under
LGPL v3 as soon as you link with GMP 4.2.2 (but then your project should
not include LGPL v2.1 only code).

Please correct me if I'w wrong,

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