Deviations from Python semantics
================================

Integer width
-------------

While Python has arbitrary-sized integers, integers in Numba-compiled
functions get a fixed size (either through :term:`type inference`, or
from an explicit specification by the user).  This means that arithmetic
operations can wrapround or produce undefined results or overflow.

Global and closure variables
----------------------------

In :term:`nopython mode`, global and closure variables are *frozen* by
Numba: a Numba-compiled function sees the value of those variables at the
time the function was compiled.  Also, it is not possible to change their
values from the function.


.. todo:: This document needs completing.