[Python-Dev] PEP 3118: Extended buffer protocol (new version) (original) (raw)

Carl Banks pythondev at aerojockey.com
Tue Apr 10 01:59:41 CEST 2007

Travis Oliphant wrote:

Py_BUF_READONLY The returned buffer must be readonly and the underlying object should make its memory readonly if that is possible.

I don't like the "if possible" thing. If it makes no guarantees, it pretty much useless over Py_BUF_SIMPLE.

PyBUFFORMAT The consumer will be using the format string information so make sure that member is filled correctly.

Is the idea to throw an exception if there's some other data format besides "b", and this flag isn't set? It seems superfluous otherwise.

PyBUFSHAPE The consumer can (and might) make use of using the ndims and shape members of the structure so make sure they are filled in correctly.

PyBUFSTRIDES (implies SHAPE) The consumer can (and might) make use of the strides member of the structure (as well as ndims and shape)

Is there any reasonable benefit for allowing Py_BUF_SHAPE without Py_BUF_STRIDES? Would the array be C- or Fortran-like?

Another little mistake I made: looking at the Python source, it seems that most C defines do not use the Py_ prefix, so probably we shouldn't here. Sorry.

Carl

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