[New-bugs-announce] [issue19803] memoryview complain ctypes byte array are not native single character

[HCT]

New submission from HCT:

I'm trying to create ctypes buffer to be used back and forth with C libraries, but I keep getting errors. I need to slice the buffer to cut out different pieces to work on, so I try to get a memoryview of the buffer. does the error message imply that c_ubyte, c_uint8, c_byte and c_char are not native single character types?

>>> memoryview(c_ubyte()).cast('B')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: memoryview: source format must be a native single character format prefixed with an optional '@'
>>> memoryview((c_ubyte*1024)()).cast('B')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: memoryview: source format must be a native single character format prefixed with an optional '@'
>>> memoryview(c_uint8()).cast('B')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: memoryview: source format must be a native single character format prefixed with an optional '@'
>>> memoryview((c_uint8*1024)()).cast('B')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: memoryview: source format must be a native single character format prefixed with an optional '@'
>>> memoryview((c_byte*1024)()).cast('B')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: memoryview: source format must be a native single character format prefixed with an optional '@'
>>> memoryview((c_char*1024)()).cast('B')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: memoryview: source format must be a native single character format prefixed with an optional '@'
>>> memoryview((c_char*1024)())[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NotImplementedError: memoryview: unsupported format (1024)<c
>>> memoryview((c_byte*1024)())[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NotImplementedError: memoryview: unsupported format (1024)<b
>>> memoryview((c_ubyte*1024)())[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NotImplementedError: memoryview: unsupported format (1024)<B
>>> memoryview((c_uint8*1024)())[0]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
NotImplementedError: memoryview: unsupported format (1024)<B
>>>

----------
components: Library (Lib), ctypes
messages: 204536
nosy: hct
priority: normal
severity: normal
status: open
title: memoryview complain ctypes byte array are not native single character
versions: Python 3.3

_______________________________________
Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue19803>
_______________________________________