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author | Georg Brandl <georg@python.org> | 2008-01-19 22:08:21 (GMT) |
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committer | Georg Brandl <georg@python.org> | 2008-01-19 22:08:21 (GMT) |
commit | f6842722df69a40e841c045d42a538bb5d6bbbf6 (patch) | |
tree | 2b8bb1b6bb5908ed66ed72f7c84de0a34ddc7542 /Doc/c-api/weakref.rst | |
parent | 8b506e7a2d4e8cb6ffd6b7f2845e45aa92daa4d4 (diff) | |
download | cpython-f6842722df69a40e841c045d42a538bb5d6bbbf6.zip cpython-f6842722df69a40e841c045d42a538bb5d6bbbf6.tar.gz cpython-f6842722df69a40e841c045d42a538bb5d6bbbf6.tar.bz2 |
Split the monstrous C API manual files in smaller parts.
Diffstat (limited to 'Doc/c-api/weakref.rst')
-rw-r--r-- | Doc/c-api/weakref.rst | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/Doc/c-api/weakref.rst b/Doc/c-api/weakref.rst new file mode 100644 index 0000000..80ebf82 --- /dev/null +++ b/Doc/c-api/weakref.rst @@ -0,0 +1,76 @@ +.. 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. + + +.. cfunction:: int PyWeakref_Check(ob) + + Return true if *ob* is either a reference or proxy object. + + .. versionadded:: 2.2 + + +.. cfunction:: int PyWeakref_CheckRef(ob) + + Return true if *ob* is a reference object. + + .. versionadded:: 2.2 + + +.. cfunction:: int PyWeakref_CheckProxy(ob) + + Return true if *ob* is a proxy object. + + .. versionadded:: 2.2 + + +.. cfunction:: 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`. + + .. versionadded:: 2.2 + + +.. cfunction:: 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`. + + .. versionadded:: 2.2 + + +.. cfunction:: PyObject* PyWeakref_GetObject(PyObject *ref) + + Return the referenced object from a weak reference, *ref*. If the referent is + no longer live, returns ``None``. + + .. versionadded:: 2.2 + + +.. cfunction:: PyObject* PyWeakref_GET_OBJECT(PyObject *ref) + + Similar to :cfunc:`PyWeakref_GetObject`, but implemented as a macro that does no + error checking. + + .. versionadded:: 2.2 |