參照計數
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本節中的巨集用於管理 Python 物件的參照計數。

void Py_INCREF(PyObject *o)

   Indicate taking a new *strong reference* to object *o*, indicating
   it is in use and should not be destroyed.

   此函式通常用於將*借用參照*原地 (in-place) 轉換為*強參照*。
   "Py_NewRef()" 函式可用於建立新的*強參照*。

   When done using the object, release it by calling "Py_DECREF()".

   該物件不能為 "NULL"；如果你不確定它不是 "NULL"，請使用
   "Py_XINCREF()"。

   Do not expect this function to actually modify *o* in any way.

void Py_XINCREF(PyObject *o)

   Similar to "Py_INCREF()", but the object *o* can be "NULL", in
   which case this has no effect.

   另請見 "Py_XNewRef()"。

PyObject *Py_NewRef(PyObject *o)
    * Part of the Stable ABI since version 3.10.*

   Create a new *strong reference* to an object: call "Py_INCREF()" on
   *o* and return the object *o*.

   When the *strong reference* is no longer needed, "Py_DECREF()"
   should be called on it to release the reference.

   物件 *o* 不能為 "NULL"；如果 *o* 可以為 "NULL"，則使用
   "Py_XNewRef()"。

   舉例來說：

      Py_INCREF(obj);
      self->attr = obj;

   可以寫成：

      self->attr = Py_NewRef(obj);

   另請參閱 "Py_INCREF()"。

   在 3.10 版新加入.

PyObject *Py_XNewRef(PyObject *o)
    * Part of the Stable ABI since version 3.10.*

   與 "Py_NewRef()" 類似，但物件 *o* 可以為 NULL。

   如果物件 *o* 為 "NULL"，則該函式僅回傳 "NULL"。

   在 3.10 版新加入.

void Py_DECREF(PyObject *o)

   Release a *strong reference* to object *o*, indicating the
   reference is no longer used.

   Once the last *strong reference* is released (i.e. the object's
   reference count reaches 0), the object's type's deallocation
   function (which must not be "NULL") is invoked.

   此函式通常用於在退出作用域之前刪除*強參照*。

   該物件不能為 "NULL"；如果你不確定它不是 "NULL"，請改用
   "Py_XDECREF()"。

   Do not expect this function to actually modify *o* in any way.

   警告:

     The deallocation function can cause arbitrary Python code to be
     invoked (e.g. when a class instance with a "__del__()" method is
     deallocated).  While exceptions in such code are not propagated,
     the executed code has free access to all Python global variables.
     This means that any object that is reachable from a global
     variable should be in a consistent state before "Py_DECREF()" is
     invoked.  For example, code to delete an object from a list
     should copy a reference to the deleted object in a temporary
     variable, update the list data structure, and then call
     "Py_DECREF()" for the temporary variable.

void Py_XDECREF(PyObject *o)

   Similar to "Py_DECREF()", but the object *o* can be "NULL", in
   which case this has no effect. The same warning from "Py_DECREF()"
   applies here as well.

void Py_CLEAR(PyObject *o)

   Release a *strong reference* for object *o*. The object may be
   "NULL", in which case the macro has no effect; otherwise the effect
   is the same as for "Py_DECREF()", except that the argument is also
   set to "NULL".  The warning for "Py_DECREF()" does not apply with
   respect to the object passed because the macro carefully uses a
   temporary variable and sets the argument to "NULL" before releasing
   the reference.

   It is a good idea to use this macro whenever releasing a reference
   to an object that might be traversed during garbage collection.

void Py_IncRef(PyObject *o)
    * Part of the Stable ABI.*

   Indicate taking a new *strong reference* to object *o*. A function
   version of "Py_XINCREF()". It can be used for runtime dynamic
   embedding of Python.

void Py_DecRef(PyObject *o)
    * Part of the Stable ABI.*

   Release a *strong reference* to object *o*. A function version of
   "Py_XDECREF()". It can be used for runtime dynamic embedding of
   Python.

以下函式或巨集僅在直譯器核心內使用："_Py_Dealloc()"、
"_Py_ForgetReference()"、"_Py_NewReference()" 以及全域變數
"_Py_RefTotal"。
