[Python-Dev] Optionally using GMP to implement long if available

[Stephen J. Turnbull]

Thomas Wouters writes:

 > Neither of those (shipping sources or dynamically linking to GMP) would
 > solve the LGPL issue. People who distribute that build of Python would still
 > be held by the LGPL -- such as shipping any sources that they embed that
 > Python into.

No, that's exactly what the "L" in "LGPL" means.  You only have to
ship the sources to any object module (library or program) actually
containing GMP code, including any modifications you make to them.  So
if GMP is kept entirely in a separate library and you don't borrow any
code from it, the rest of your code is not affected by the LGPL.

This includes any marshalling code that does nothing but load the GMP
library and connect it up to Python's internal API; that need not be
LGPL unless you add it to the GMP library.

The "problem" with the LGPL is the administrative burden of tracking
which sources need to be distributed under what conditions, not that
it insinuates itself into your own code.