[Cython] A few suggestions for the numpy tutorial documentation...

[Dag Sverre Seljebotn]

> Hi all,
>
> I've spent the day writing a Numpy format handler in Cython and thought
> there were a few things that the Cython numpy tutorial possibly should
> cover:

Are you talking about wiki.cython.org/tutorials/numpy? I think that's
targeted to a a different audience who don't immedeately feel comfortable
calling the NumPy C API...

>     * Numpy dtype references appear to be normally "borrowed" references
>       in the C API, so when you call numpy array functions that take a
>       dtype you need to Py_INCREF the dtype first, this will show up as
>       complaints from numpy that you're trying to delete the dtype objects

Good point.

>     * You have to call import_array() in your module or many of the
>       Numpy C API entry points will segfault

Are you sure about this? I never do it. I know you need to do it from C
code, but is it not enough in Cython to do

import numpy

?

Did you actually get a segfault using Cython? Could you send me an
example? I'd really like to make this automatic somehow.

> Anyway, not sure if or where such changes should go, but just thought it
> might help others.

I you feel it fits within the tutorial feel free to add it there,
otherwise you can always create a sub-page about "Using the NumPy C API"
or somesuch.

Dag Sverre