# Contagem de Referências

As macros nesta seção são usadas para gerenciar contagens de referências de objetos Python.

void `Py_INCREF`(PyObject *o)

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

  This function is usually used to convert a borrowed reference to a strong reference in-place. The `Py_NewRef()` function can be used to create a new strong reference.

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

  The object must not be `NULL`; if you aren’t sure that it isn’t `NULL`, use `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.

  See also `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.

  The object o must not be `NULL`; use `Py_XNewRef()` if o can be `NULL`.

  Por exemplo:

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

  can be written as:

      self->attr = Py_NewRef(obj);

  See also `Py_INCREF()`.

  Novo na versão 3.10.

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

  Similar to `Py_NewRef()`, but the object o can be NULL.

  If the object o is `NULL`, the function just returns `NULL`.

  Novo na versão 3.10.

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.

  This function is usually used to delete a strong reference before exiting its scope.

  The object must not be `NULL`; if you aren’t sure that it isn’t `NULL`, use `Py_XDECREF()`.

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

  Aviso

  A função de desalocação pode fazer com que o código Python arbitrário seja invocado (por exemplo, quando uma instância de classe com um método `__del__()` é desalocada). Embora as exceções em tal código não sejam propagadas, o código executado tem acesso livre a todas as variáveis globais do Python. Isso significa que qualquer objeto que é alcançável de uma variável global deve estar em um estado consistente antes de `Py_DECREF()` ser invocado. Por exemplo, o código para excluir um objeto de uma lista deve copiar uma referência ao objeto excluído em uma variável temporária, atualizar a estrutura de dados da lista e então chamar `Py_DECREF()` para a variável temporária.

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.

As seguintes funções ou macros são apenas para uso dentro do núcleo do interpretador: `_Py_Dealloc()`, `_Py_ForgetReference()`, `_Py_NewReference()`, bem como a variável global `_Py_RefTotal`.