弱參照物件¶
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.
-
int
PyWeakref_Check
(ob)¶ Return true if ob is either a reference or proxy object.
-
int
PyWeakref_CheckRef
(ob)¶ Return true if ob is a reference object.
-
int
PyWeakref_CheckProxy
(ob)¶ Return true if ob is a proxy object.
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PyObject*
PyWeakref_NewRef
(PyObject *ob, PyObject *callback)¶ - Return value: New reference.
返回对象 ob 的一个弱引用对象。 该函数总是会返回一个新的引用,但不保证创建一个新的对象;它有可能返回一个现有的引用对象。 第二个形参 callback 为一个可调用对象,它会在 ob 被作为垃圾回收时接收通知;它应该接受一个单独形参,即弱引用对象本身。 callback 也可以为
None
或NULL
。 如果 ob 不是一个弱引用对象,或者如果 callback 不是可调用对象,None
或NULL
,该函数将返回NULL
并且引发TypeError
。
-
PyObject*
PyWeakref_NewProxy
(PyObject *ob, PyObject *callback)¶ - Return value: New reference.
返回对象 ob 的一个弱引用代理对象。 该函数将总是返回一个新的引用,但不保证创建一个新的对象;它有可能返回一个现有的代理对象。 第二个形参 callback 为一个可调用对象,它会在 ob 被作为垃圾回收时接收通知;它应该接受一个单独形参,即弱引用对象本身。 callback 也可以为
None
或NULL
。 如果 ob 不是一个弱引用对象,或者如果 callback 不是可调用对象,None
或NULL
,该函数将返回NULL
并且引发TypeError
。
-
PyObject*
PyWeakref_GetObject
(PyObject *ref)¶ - Return value: Borrowed reference.
Return the referenced object from a weak reference, ref. If the referent is no longer live, returns
Py_None
.備註
This function returns a borrowed reference to the referenced object. This means that you should always call
Py_INCREF()
on the object except if you know that it cannot be destroyed while you are still using it.
-
PyObject*
PyWeakref_GET_OBJECT
(PyObject *ref)¶ - Return value: Borrowed reference.
Similar to
PyWeakref_GetObject()
, but implemented as a macro that does no error checking.