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svn+ssh://pythondev@svn.python.org/python/branches/py3k ........ r83536 | georg.brandl | 2010-08-02 19:49:25 +0200 (Mo, 02 Aug 2010) | 1 line #8578: mention danger of not incref'ing weak referenced object. ........ r83546 | georg.brandl | 2010-08-02 21:16:34 +0200 (Mo, 02 Aug 2010) | 1 line #7973: Fix distutils options spelling. ........ r83547 | georg.brandl | 2010-08-02 21:19:26 +0200 (Mo, 02 Aug 2010) | 1 line #7386: add example that shows that trailing path separators are stripped. ........ r83548 | georg.brandl | 2010-08-02 21:23:34 +0200 (Mo, 02 Aug 2010) | 1 line #8172: how does one use a property? ........ r83550 | georg.brandl | 2010-08-02 21:32:43 +0200 (Mo, 02 Aug 2010) | 1 line #9451: strengthen warning about __*__ special name usage. ........ r83554 | georg.brandl | 2010-08-02 21:43:05 +0200 (Mo, 02 Aug 2010) | 1 line #7280: note about nasmw.exe. ........ r83555 | georg.brandl | 2010-08-02 21:44:48 +0200 (Mo, 02 Aug 2010) | 1 line #8861: remove unused variable. ........ r83558 | georg.brandl | 2010-08-02 22:05:19 +0200 (Mo, 02 Aug 2010) | 1 line #8648: document UTF-7 codec functions. ........ r83563 | georg.brandl | 2010-08-02 22:21:21 +0200 (Mo, 02 Aug 2010) | 1 line #9037: add example how to raise custom exceptions from C code. ........ r83565 | georg.brandl | 2010-08-02 22:27:20 +0200 (Mo, 02 Aug 2010) | 1 line #9111: document that do_help() looks at docstrings. ........ r83571 | georg.brandl | 2010-08-02 22:44:34 +0200 (Mo, 02 Aug 2010) | 1 line Clarify that abs() is not a namespace. ........ r83574 | georg.brandl | 2010-08-02 22:47:56 +0200 (Mo, 02 Aug 2010) | 1 line #6867: epoll.register() returns None. ........ r83575 | georg.brandl | 2010-08-02 22:52:10 +0200 (Mo, 02 Aug 2010) | 1 line #9238: zipfile does handle archive comments. ........
83 lines
2.7 KiB
ReStructuredText
83 lines
2.7 KiB
ReStructuredText
.. highlightlang:: c
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.. _weakrefobjects:
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Weak Reference Objects
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----------------------
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Python supports *weak references* as first-class objects. There are two
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specific object types which directly implement weak references. The first is a
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simple reference object, and the second acts as a proxy for the original object
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as much as it can.
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.. cfunction:: int PyWeakref_Check(ob)
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Return true if *ob* is either a reference or proxy object.
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.. versionadded:: 2.2
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.. cfunction:: int PyWeakref_CheckRef(ob)
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Return true if *ob* is a reference object.
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.. versionadded:: 2.2
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.. cfunction:: int PyWeakref_CheckProxy(ob)
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Return true if *ob* is a proxy object.
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.. versionadded:: 2.2
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.. cfunction:: PyObject* PyWeakref_NewRef(PyObject *ob, PyObject *callback)
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Return a weak reference object for the object *ob*. This will always return
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a new reference, but is not guaranteed to create a new object; an existing
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reference object may be returned. The second parameter, *callback*, can be a
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callable object that receives notification when *ob* is garbage collected; it
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should accept a single parameter, which will be the weak reference object
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itself. *callback* may also be ``None`` or *NULL*. If *ob* is not a
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weakly-referencable object, or if *callback* is not callable, ``None``, or
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*NULL*, this will return *NULL* and raise :exc:`TypeError`.
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.. versionadded:: 2.2
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.. cfunction:: PyObject* PyWeakref_NewProxy(PyObject *ob, PyObject *callback)
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Return a weak reference proxy object for the object *ob*. This will always
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return a new reference, but is not guaranteed to create a new object; an
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existing proxy object may be returned. The second parameter, *callback*, can
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be a callable object that receives notification when *ob* is garbage
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collected; it should accept a single parameter, which will be the weak
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reference object itself. *callback* may also be ``None`` or *NULL*. If *ob*
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is not a weakly-referencable object, or if *callback* is not callable,
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``None``, or *NULL*, this will return *NULL* and raise :exc:`TypeError`.
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.. versionadded:: 2.2
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.. cfunction:: PyObject* PyWeakref_GetObject(PyObject *ref)
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Return the referenced object from a weak reference, *ref*. If the referent is
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no longer live, returns :const:`Py_None`.
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.. versionadded:: 2.2
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.. warning::
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This function returns a **borrowed reference** to the referenced object.
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This means that you should always call :cfunc:`Py_INCREF` on the object
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except if you know that it cannot be destroyed while you are still
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using it.
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.. cfunction:: PyObject* PyWeakref_GET_OBJECT(PyObject *ref)
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Similar to :cfunc:`PyWeakref_GetObject`, but implemented as a macro that does no
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error checking.
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.. versionadded:: 2.2
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