[Cython] C int division by zero

[Dag Sverre Seljebotn]

I was just thinking about this:

     cdef int a = 10, b = 0
     print a // b

which currently gives a C exception terminating the Python interpreter.

On one hand: We have already changed division to Python behaviour (with 
a speed penalty); so using the same arguments (which I won't reiterate) 
it would make sense to raise a Python exception instead here.

It seems to make sense to couple this as well to the cdivision directive 
and cython.cdiv function.

On the other hand: Well, all the arguments that was against changing // 
to Python behaviour.

But in addition:

This is coupled with the "exception under nogil" issue that I raised in 
another thread today, as one should definitely be allowed to do C 
division within a nogil section.

One solution would be to work on accepting exceptions under nogil, 
another one would be to require use of cdivision directive/cdiv to do 
division in nogil sections.

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Dag Sverre