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cpython/Doc/c-api/memoryview.rst
Antoine Pitrou 6ec5ed22b2 Merged revisions 85084 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/branches/py3k

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  r85084 | antoine.pitrou | 2010-09-29 01:59:51 +0200 (mer., 29 sept. 2010) | 5 lines

  Give a dedicated page to memoryview objects, so that they can be part
  of the concrete objects layer, while the buffer protocol is part of
  the abstract objects layer.
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2010-09-29 00:01:41 +00:00

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.. highlightlang:: c
.. _memoryview-objects:
.. index::
object: memoryview
MemoryView objects
------------------
A :class:`memoryview` object exposes the C level :ref:`buffer interface
<bufferobjects>` as a Python object which can then be passed around like
any other object.
.. cfunction:: PyObject *PyMemoryView_FromObject(PyObject *obj)
Create a memoryview object from an object that provides the buffer interface.
If *obj* supports writable buffer exports, the memoryview object will be
readable and writable, other it will be read-only.
.. cfunction:: PyObject *PyMemoryView_FromBuffer(Py_buffer *view)
Create a memoryview object wrapping the given buffer structure *view*.
The memoryview object then owns the buffer represented by *view*, which
means you shouldn't try to call :cfunc:`PyBuffer_Release` yourself: it
will be done on deallocation of the memoryview object.
.. cfunction:: PyObject *PyMemoryView_GetContiguous(PyObject *obj, int buffertype, char order)
Create a memoryview object to a contiguous chunk of memory (in either
'C' or 'F'ortran *order*) from an object that defines the buffer
interface. If memory is contiguous, the memoryview object points to the
original memory. Otherwise copy is made and the memoryview points to a
new bytes object.
.. cfunction:: int PyMemoryView_Check(PyObject *obj)
Return true if the object *obj* is a memoryview object. It is not
currently allowed to create subclasses of :class:`memoryview`.
.. cfunction:: Py_buffer *PyMemoryView_GET_BUFFER(PyObject *obj)
Return a pointer to the buffer structure wrapped by the given
memoryview object. The object **must** be a memoryview instance;
this macro doesn't check its type, you must do it yourself or you
will risk crashes.