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 ( PyObject * ob ) ¶

返回 True 若 ob is either a reference or proxy object. This function always succeeds.

int PyWeakref_CheckRef ( PyObject * ob ) ¶

返回 True 若 ob is a reference object. This function always succeeds.

int PyWeakref_CheckProxy ( PyObject * ob ) ¶

返回 True 若 ob is a proxy object. This function always succeeds.

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

返回值：新引用。 属于 稳定 ABI (应用程序二进制接口) .

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 还可以为 None or NULL 。若 ob is not a weakly referenceable 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。 属于 稳定 ABI (应用程序二进制接口) .

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 还可以为 None or NULL 。若 ob is not a weakly referenceable 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。 属于 稳定 ABI (应用程序二进制接口) .

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 借位引用 to the referenced object. This means that you should always call Py_INCREF() on the object except when it cannot be destroyed before the last usage of the borrowed reference.

PyObject * PyWeakref_GET_OBJECT ( PyObject * ref ) ¶

返回值：借位引用。

类似于 PyWeakref_GetObject() , but does no error checking.

void PyObject_ClearWeakRefs ( PyObject * object ) ¶

属于 稳定 ABI (应用程序二进制接口) .

此函数被调用通过 tp_dealloc handler to clear weak references.

This iterates through the weak references for object and calls callbacks for those references which have one. It returns when all callbacks have been attempted.

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