mirror of https://github.com/python/cpython
56 lines
2.4 KiB
ReStructuredText
56 lines
2.4 KiB
ReStructuredText
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.. highlight:: c
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Old Buffer Protocol
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-------------------
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.. deprecated:: 3.0
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These functions were part of the "old buffer protocol" API in Python 2.
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In Python 3, this protocol doesn't exist anymore but the functions are still
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exposed to ease porting 2.x code. They act as a compatibility wrapper
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around the :ref:`new buffer protocol <bufferobjects>`, but they don't give
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you control over the lifetime of the resources acquired when a buffer is
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exported.
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Therefore, it is recommended that you call :c:func:`PyObject_GetBuffer`
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(or the ``y*`` or ``w*`` :ref:`format codes <arg-parsing>` with the
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:c:func:`PyArg_ParseTuple` family of functions) to get a buffer view over
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an object, and :c:func:`PyBuffer_Release` when the buffer view can be released.
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.. c:function:: int PyObject_AsCharBuffer(PyObject *obj, const char **buffer, Py_ssize_t *buffer_len)
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Returns a pointer to a read-only memory location usable as character-based
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input. The *obj* argument must support the single-segment character buffer
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interface. On success, returns ``0``, sets *buffer* to the memory location
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and *buffer_len* to the buffer length. Returns ``-1`` and sets a
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:exc:`TypeError` on error.
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.. c:function:: int PyObject_AsReadBuffer(PyObject *obj, const void **buffer, Py_ssize_t *buffer_len)
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Returns a pointer to a read-only memory location containing arbitrary data.
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The *obj* argument must support the single-segment readable buffer
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interface. On success, returns ``0``, sets *buffer* to the memory location
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and *buffer_len* to the buffer length. Returns ``-1`` and sets a
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:exc:`TypeError` on error.
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.. c:function:: int PyObject_CheckReadBuffer(PyObject *o)
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Returns ``1`` if *o* supports the single-segment readable buffer interface.
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Otherwise returns ``0``. This function always succeeds.
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Note that this function tries to get and release a buffer, and exceptions
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which occur while calling corresponding functions will get suppressed.
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To get error reporting use :c:func:`PyObject_GetBuffer()` instead.
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.. c:function:: int PyObject_AsWriteBuffer(PyObject *obj, void **buffer, Py_ssize_t *buffer_len)
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Returns a pointer to a writable memory location. The *obj* argument must
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support the single-segment, character buffer interface. On success,
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returns ``0``, sets *buffer* to the memory location and *buffer_len* to the
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buffer length. Returns ``-1`` and sets a :exc:`TypeError` on error.
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