Would it be possible to elaborate how to replace the 3 "As" functions withPyObject_GetBuffer() flags? I'm not used this Py_buffer API. AsCharBuffer() useconst char ** type and AsReadBuffer() useconst void **buffer type: constant. ButPyBuffer.buf type isvoid*, it's mutable. Maybe add a note about casting if needed? Or provide a full recipe. I don't know.

How do you replacebuffer_len? Is itPy_buffer.len orPy_buffer.itemsize? It's a honest question, I don't know the answer :-(

You may also mention that PyObject_CheckReadBuffer() ignores any kind of exception, whereas PyObject_GetBuffer() can raise different exceptions. What is the expected exception if a type doesn't support the buffer protocol?