弱引用对象 ¶

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 ) ¶

返回 True 若 ob is either a reference or proxy object.

int PyWeakref_CheckRef ( ob ) ¶

返回 True 若 ob is a reference object.

int PyWeakref_CheckProxy ( ob ) ¶

返回 True 若 ob is a proxy object.

PyObject * PyWeakref_NewRef ( PyObject  *ob , PyObject  *callback ) ¶

返回值：新引用。

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 。若 ob is not a weakly-referencable object, or if callback is not callable, None ，或 NULL , this will return NULL and raise TypeError .

PyObject * PyWeakref_NewProxy ( PyObject  *ob , PyObject  *callback ) ¶

返回值：新引用。

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 。若 ob is not a weakly-referencable object, or if callback is not callable, None ，或 NULL , this will return NULL and raise TypeError .

PyObject * PyWeakref_GetObject ( PyObject  *ref ) ¶

返回值：借位引用。

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

注意

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 ) ¶

返回值：借位引用。

类似 PyWeakref_GetObject() , but implemented as a macro that does no error checking.

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