1 .. highlightlang:: c 2 3 Old Buffer Protocol 4 ------------------- 5 6 .. deprecated:: 3.0 7 8 These functions were part of the "old buffer protocol" API in Python 2. 9 In Python 3, this protocol doesn't exist anymore but the functions are still 10 exposed to ease porting 2.x code. They act as a compatibility wrapper 11 around the :ref:`new buffer protocol <bufferobjects>`, but they don't give 12 you control over the lifetime of the resources acquired when a buffer is 13 exported. 14 15 Therefore, it is recommended that you call :c:func:`PyObject_GetBuffer` 16 (or the ``y*`` or ``w*`` :ref:`format codes <arg-parsing>` with the 17 :c:func:`PyArg_ParseTuple` family of functions) to get a buffer view over 18 an object, and :c:func:`PyBuffer_Release` when the buffer view can be released. 19 20 21 .. c:function:: int PyObject_AsCharBuffer(PyObject *obj, const char **buffer, Py_ssize_t *buffer_len) 22 23 Returns a pointer to a read-only memory location usable as character-based 24 input. The *obj* argument must support the single-segment character buffer 25 interface. On success, returns ``0``, sets *buffer* to the memory location 26 and *buffer_len* to the buffer length. Returns ``-1`` and sets a 27 :exc:`TypeError` on error. 28 29 30 .. c:function:: int PyObject_AsReadBuffer(PyObject *obj, const void **buffer, Py_ssize_t *buffer_len) 31 32 Returns a pointer to a read-only memory location containing arbitrary data. 33 The *obj* argument must support the single-segment readable buffer 34 interface. On success, returns ``0``, sets *buffer* to the memory location 35 and *buffer_len* to the buffer length. Returns ``-1`` and sets a 36 :exc:`TypeError` on error. 37 38 39 .. c:function:: int PyObject_CheckReadBuffer(PyObject *o) 40 41 Returns ``1`` if *o* supports the single-segment readable buffer interface. 42 Otherwise returns ``0``. This function always succeeds. 43 44 Note that this function tries to get and release a buffer, and exceptions 45 which occur while calling corresponding functions will get suppressed. 46 To get error reporting use :c:func:`PyObject_GetBuffer()` instead. 47 48 49 .. c:function:: int PyObject_AsWriteBuffer(PyObject *obj, void **buffer, Py_ssize_t *buffer_len) 50 51 Returns a pointer to a writable memory location. The *obj* argument must 52 support the single-segment, character buffer interface. On success, 53 returns ``0``, sets *buffer* to the memory location and *buffer_len* to the 54 buffer length. Returns ``-1`` and sets a :exc:`TypeError` on error. 55 56
