FM / c-api

/usr/share/doc/python3-docs/html/_sources/c-api/

/usr/share/doc/python3-docs/html/_sources/c-api

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abstract.rst.txt	715	0644	edit dl rm
allocation.rst.txt	2653	0644	edit dl rm
apiabiversion.rst.txt	2242	0644	edit dl rm
arg.rst.txt	30651	0644	edit dl rm
bool.rst.txt	1200	0644	edit dl rm
buffer.rst.txt	22267	0644	edit dl rm
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datetime.rst.txt	6415	0644	edit dl rm
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exceptions.rst.txt	47814	0644	edit dl rm
file.rst.txt	3248	0644	edit dl rm
float.rst.txt	2243	0644	edit dl rm
function.rst.txt	3348	0644	edit dl rm
gcsupport.rst.txt	6057	0644	edit dl rm
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objimpl.rst.txt	304	0644	edit dl rm
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unicode.rst.txt	68074	0644	edit dl rm
utilities.rst.txt	414	0644	edit dl rm
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weakref.rst.txt	2635	0644	edit dl rm

Edit: /usr/share/doc/python3-docs/html/_sources/c-api/weakref.rst.txt (2635B)

.. highlightlang:: c

.. _weakrefobjects:

Weak Reference Objects
----------------------

Python supports *weak references* as first-class objects.  There are two
specific object types which directly implement weak references.  The first is a
simple reference object, and the second acts as a proxy for the original object
as much as it can.

.. c:function:: int PyWeakref_Check(ob)

Return true if *ob* is either a reference or proxy object.

.. c:function:: int PyWeakref_CheckRef(ob)

Return true if *ob* is a reference object.

.. c:function:: int PyWeakref_CheckProxy(ob)

Return true if *ob* is a proxy object.

.. c:function:: PyObject* PyWeakref_NewRef(PyObject *ob, PyObject *callback)

Return a weak reference object for the object *ob*.  This will always return
   a new reference, but is not guaranteed to create a new object; an existing
   reference object may be returned.  The second parameter, *callback*, can be a
   callable object that receives notification when *ob* is garbage collected; it
   should accept a single parameter, which will be the weak reference object
   itself. *callback* may also be ``None`` or *NULL*.  If *ob* is not a
   weakly-referencable object, or if *callback* is not callable, ``None``, or
   *NULL*, this will return *NULL* and raise :exc:`TypeError`.

.. c:function:: PyObject* PyWeakref_NewProxy(PyObject *ob, PyObject *callback)

Return a weak reference proxy object for the object *ob*.  This will always
   return a new reference, but is not guaranteed to create a new object; an
   existing proxy object may be returned.  The second parameter, *callback*, can
   be a callable object that receives notification when *ob* is garbage
   collected; it should accept a single parameter, which will be the weak
   reference object itself. *callback* may also be ``None`` or *NULL*.  If *ob*
   is not a weakly-referencable object, or if *callback* is not callable,
   ``None``, or *NULL*, this will return *NULL* and raise :exc:`TypeError`.

.. c:function:: PyObject* PyWeakref_GetObject(PyObject *ref)

Return the referenced object from a weak reference, *ref*.  If the referent is
   no longer live, returns :const:`Py_None`.

.. note::

This function returns a **borrowed reference** to the referenced object.
      This means that you should always call :c:func:`Py_INCREF` on the object
      except if you know that it cannot be destroyed while you are still
      using it.

.. c:function:: PyObject* PyWeakref_GET_OBJECT(PyObject *ref)

Similar to :c:func:`PyWeakref_GetObject`, but implemented as a macro that does no
   error checking.

cmd: