memory view over 'bytes', incorrect doc?

Hi! I was trying to write a function accepting string/bytes and returning string/bytes again. I found an example of accepting strings in the documentation: https://cython.readthedocs.io/en/latest/src/tutorial/strings.html#accepting-strings-from-python-code

but it doesn’t work:

def process_byte_data(unsigned char[:] data):
    length = data.shape[0]
    first_byte = data[0]
    slice_view = data[1:-1]

b = b'asd'
process_byte_data(b)

results in

BufferError: Object is not writable.

(Relevant topic in mailing list: https://groups.google.com/d/topic/cython-users/32CMgaLrNhc/discussion)

[TeamSpen210]

You need to specify it as const, since bytes is readonly. That should probably be highlighted more in the tutorial.

[scoder]

You need to specify it as const, since bytes is readonly. That should probably be highlighted more in the tutorial.

Absolutely. Docs PR welcome.