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76 lines
2.5 KiB
ReStructuredText
76 lines
2.5 KiB
ReStructuredText
.. highlight:: c
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.. _memoryview-objects:
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.. index::
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pair: object; memoryview
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MemoryView objects
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------------------
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A :class:`memoryview` object exposes the C level :ref:`buffer interface
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<bufferobjects>` as a Python object which can then be passed around like
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any other object.
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.. c:function:: PyObject *PyMemoryView_FromObject(PyObject *obj)
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Create a memoryview object from an object that provides the buffer interface.
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If *obj* supports writable buffer exports, the memoryview object will be
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read/write, otherwise it may be either read-only or read/write at the
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discretion of the exporter.
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.. c:macro:: PyBUF_READ
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Flag to request a readonly buffer.
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.. c:macro:: PyBUF_WRITE
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Flag to request a writable buffer.
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.. c:function:: PyObject *PyMemoryView_FromMemory(char *mem, Py_ssize_t size, int flags)
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Create a memoryview object using *mem* as the underlying buffer.
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*flags* can be one of :c:macro:`PyBUF_READ` or :c:macro:`PyBUF_WRITE`.
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.. versionadded:: 3.3
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.. c:function:: PyObject *PyMemoryView_FromBuffer(const Py_buffer *view)
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Create a memoryview object wrapping the given buffer structure *view*.
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For simple byte buffers, :c:func:`PyMemoryView_FromMemory` is the preferred
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function.
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.. c:function:: PyObject *PyMemoryView_GetContiguous(PyObject *obj, int buffertype, char order)
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Create a memoryview object to a :term:`contiguous` chunk of memory (in either
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'C' or 'F'ortran *order*) from an object that defines the buffer
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interface. If memory is contiguous, the memoryview object points to the
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original memory. Otherwise, a copy is made and the memoryview points to a
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new bytes object.
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*buffertype* can be one of :c:macro:`PyBUF_READ` or :c:macro:`PyBUF_WRITE`.
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.. c:function:: int PyMemoryView_Check(PyObject *obj)
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Return true if the object *obj* is a memoryview object. It is not
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currently allowed to create subclasses of :class:`memoryview`. This
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function always succeeds.
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.. c:function:: Py_buffer *PyMemoryView_GET_BUFFER(PyObject *mview)
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Return a pointer to the memoryview's private copy of the exporter's buffer.
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*mview* **must** be a memoryview instance; this macro doesn't check its type,
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you must do it yourself or you will risk crashes.
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.. c:function:: PyObject *PyMemoryView_GET_BASE(PyObject *mview)
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Return either a pointer to the exporting object that the memoryview is based
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on or ``NULL`` if the memoryview has been created by one of the functions
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:c:func:`PyMemoryView_FromMemory` or :c:func:`PyMemoryView_FromBuffer`.
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*mview* **must** be a memoryview instance.
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