[Cython] Memory views: dereferencing pointer does break strict-aliasing rules

[Robert Bradshaw]

On Fri, Oct 11, 2013 at 10:46 AM, Stefan Behnel <stefan_ml at behnel.de> wrote:
> Robert Bradshaw, 11.10.2013 19:10:
>> Python and Cython in
>> general breaks pointer aliasing as objects are simultaneously generic
>> PyObject* and PyListObject*, PyDictObject*, etc. As the set of
>> possible types is large and open,  unions won't work. This is how
>> object oriented programming (with subclassing) is done in C.
>
> This has been fixed in CPython 3.x.

Ah, I wasn't even aware of that. For the curious:
http://www.python.org/dev/peps/pep-3123/

Basically, there is an exception for casting a struct pointer to a
pointer of its first member. Looking into this more, there's also an
exception for char* (aliasing is explicitly allowed), so I take back
what I said about this not being possible (due to the looseness of
"strict" aliasing in some cases) but I don't know how easy it'd be.

- Robert