[Python-Dev] Allocation of shape and strides fields in Py_buffer

[Travis Oliphant]

Antoine Pitrou wrote:
> Hello,
> 
> The Py_buffer struct has two pointers named `shape` and `strides`. Each points
> to an array of Py_ssize_t values whose length is equal to the number of
> dimensions of the buffer object. Unfortunately, the buffer protocol spec doesn't
> explain how allocation of these arrays should be handled.
>

I'm coming in late to this discussion, so I apologize for being out of 
order.   But, as Nick later clarifies, the PEP *does* specify how 
allocation of these arrays is handled.

Specifically, it is the responsibility of the exporter to do it and keep 
them correct as long as the buffer is shared.

I have not been able to keep up with the python-dev mailing lists since 
I have been working full time outside of academia.   I apologize for the 
difficulty this may have caused.  But, I have been available via email 
and am happy to respond to specific questions regarding the buffer 
protocol and its implementation.

I will make some time during December to help clean up confusing issues. 
  There are still pieces to implement as well (the enhancements to the 
struct module, for example), but I will not have time for this in the 
next 6 months because I would like to spend any time I can find on 
porting NumPy to use the new buffer protocol as part of getting NumPy 
ready for 3.0.

-Travis