1 .. highlightlang:: c 2 3 .. _abstract-buffer: 4 5 6 Old Buffer Protocol 7 =================== 8 9 This section describes the legacy buffer protocol, which has been introduced 10 in Python 1.6. It is still supported but deprecated in the Python 2.x series. 11 Python 3 introduces a new buffer protocol which fixes weaknesses and 12 shortcomings of the protocol, and has been backported to Python 2.6. See 13 :ref:`bufferobjects` for more information. 14 15 16 .. c:function:: int PyObject_AsCharBuffer(PyObject *obj, const char **buffer, Py_ssize_t *buffer_len) 17 18 Returns a pointer to a read-only memory location usable as character-based 19 input. The *obj* argument must support the single-segment character buffer 20 interface. On success, returns ``0``, sets *buffer* to the memory location 21 and *buffer_len* to the buffer length. Returns ``-1`` and sets a 22 :exc:`TypeError` on error. 23 24 .. versionadded:: 1.6 25 26 .. versionchanged:: 2.5 27 This function used an :c:type:`int *` type for *buffer_len*. This might 28 require changes in your code for properly supporting 64-bit systems. 29 30 31 .. c:function:: int PyObject_AsReadBuffer(PyObject *obj, const void **buffer, Py_ssize_t *buffer_len) 32 33 Returns a pointer to a read-only memory location containing arbitrary data. 34 The *obj* argument must support the single-segment readable buffer 35 interface. On success, returns ``0``, sets *buffer* to the memory location 36 and *buffer_len* to the buffer length. Returns ``-1`` and sets a 37 :exc:`TypeError` on error. 38 39 .. versionadded:: 1.6 40 41 .. versionchanged:: 2.5 42 This function used an :c:type:`int *` type for *buffer_len*. This might 43 require changes in your code for properly supporting 64-bit systems. 44 45 46 .. c:function:: int PyObject_CheckReadBuffer(PyObject *o) 47 48 Returns ``1`` if *o* supports the single-segment readable buffer interface. 49 Otherwise returns ``0``. 50 51 .. versionadded:: 2.2 52 53 54 .. c:function:: int PyObject_AsWriteBuffer(PyObject *obj, void **buffer, Py_ssize_t *buffer_len) 55 56 Returns a pointer to a writeable memory location. The *obj* argument must 57 support the single-segment, character buffer interface. On success, 58 returns ``0``, sets *buffer* to the memory location and *buffer_len* to the 59 buffer length. Returns ``-1`` and sets a :exc:`TypeError` on error. 60 61 .. versionadded:: 1.6 62 63 .. versionchanged:: 2.5 64 This function used an :c:type:`int *` type for *buffer_len*. This might 65 require changes in your code for properly supporting 64-bit systems. 66 67
