# 描述器对象

“描述器”是描述对象的某些属性的对象。它们存在于类型对象的字典中。

PyObject *PyDescr_NewGetSet(PyTypeObject *type, struct PyGetSetDef *getset)
  返回值：新的引用。 属于 稳定 ABI.

  根据 `PyGetSetDef` 结构体 getset 为扩展类型 type 创建一个新的 get-set 描述器。

  get-set 描述器将暴露由 C getter 和 setter 函数实现的属性而不是直接存储在实例中。 这与为 `tp_getset` 中条目创建的描述器种类相同，它将作为一个 `types.GetSetDescriptorType` 对象出现在 Python 中。

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

PyObject *PyDescr_NewMember(PyTypeObject *type, struct PyMemberDef *member)
  返回值：新的引用。 属于 稳定 ABI.

  Create a new member descriptor for extension type type from the `PyMemberDef` structure member.

  Member descriptors expose fields in the type's C struct as Python attributes. This is the same kind of descriptor created for entries in `tp_members`, and it appears in Python as a `types.MemberDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

PyTypeObject PyMemberDescr_Type
  属于 稳定 ABI.

  基于 `PyMemberDef` 结构体创建的成员描述器对象的类型对象。这种描述器将 C 结构的字段暴露为类型的属性，对应 Python 中的 `types.MemberDescriptorType` 对象。

PyTypeObject PyGetSetDescr_Type
  属于 稳定 ABI.

  The type object for get/set descriptor objects created from `PyGetSetDef` structures. These descriptors implement attributes whose value is computed by C getter and setter functions, and are used for many built-in type attributes. They correspond to `types.GetSetDescriptorType` objects in Python.

PyObject *PyDescr_NewMethod(PyTypeObject *type, struct PyMethodDef *meth)
  返回值：新的引用。 属于 稳定 ABI.

  Create a new method descriptor for extension type type from the `PyMethodDef` structure meth.

  Method descriptors expose C functions as methods on a type. This is the same kind of descriptor created for entries in `tp_methods`, and it appears in Python as a `types.MethodDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

PyTypeObject PyMethodDescr_Type
  属于 稳定 ABI.

  The type object for method descriptor objects created from `PyMethodDef` structures. These descriptors expose C functions as methods on a type, and correspond to `types.MethodDescriptorType` objects in Python.

struct wrapperbase

  Describes a slot wrapper used by `PyDescr_NewWrapper()`.

  Each `wrapperbase` record stores the Python-visible name and metadata for a special method implemented by a type slot, together with the wrapper function used to adapt that slot to Python's calling convention.

PyObject *PyDescr_NewWrapper(PyTypeObject *type, struct wrapperbase *base, void *wrapped)
  返回值：新的引用。

  Create a new wrapper descriptor for extension type type from the `wrapperbase` structure base and the wrapped slot function pointer wrapped.

  Wrapper descriptors expose special methods implemented by type slots. This is the same kind of descriptor that CPython creates for slot-based special methods such as `__repr__` or `__add__`, and it appears in Python as a `types.WrapperDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

PyTypeObject PyWrapperDescr_Type
  属于 稳定 ABI.

  由 `PyDescr_NewWrapper()` 和 `PyWrapper_New()` 创建的包装器描述器对象的类型对象。 包装器描述器在内部被用于暴露通过包装器结构体实现的特殊方法，对应 Python 中的 `types.WrapperDescriptorType` 对象。

PyObject *PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method)
  返回值：新的引用。 属于 稳定 ABI.

  Create a new class method descriptor for extension type type from the `PyMethodDef` structure method.

  Class method descriptors expose C methods that receive the class rather than an instance when accessed. This is the same kind of descriptor created for `METH_CLASS` entries in `tp_methods`, and it appears in Python as a `types.ClassMethodDescriptorType` object.

  On success, return a strong reference to the descriptor. Return `NULL` with an exception set on failure.

int PyDescr_IsData(PyObject *descr)

  如果描述器对象 descr 描述的是一个数据属性则返回非零值，或者如果它描述的是一个方法则返回 `0`。 descr 必须是一个描述器对象；不会进行错误检查。

PyObject *PyWrapper_New(PyObject *d, PyObject *self)
  返回值：新的引用。 属于 稳定 ABI.

  Create a new bound wrapper object from the wrapper descriptor d and the instance self.

  This is the bound form of a wrapper descriptor created by `PyDescr_NewWrapper()`. CPython creates these objects when a slot wrapper is accessed through an instance, and they appear in Python as `types.MethodWrapperType` objects.

  On success, return a strong reference to the wrapper object. Return `NULL` with an exception set on failure.

PyDescr_COMMON

  This is a macro including the common fields for a descriptor object.

  This was included in Python's C API by mistake; do not use it in extensions. For creating custom descriptor objects, create a class implementing the descriptor protocol (`tp_descr_get` and `tp_descr_set`).

  自 3.15 版起已处于 Soft deprecated 状态.

## 内置描述器

PyTypeObject PyProperty_Type
  属于 稳定 ABI.

  The type object for property objects. This is the same object as `property` in the Python layer.

PyTypeObject PySuper_Type
  属于 稳定 ABI.

  super 对象的类型对象。它与 Python 层面的 `super` 是相同的对象。

PyTypeObject PyClassMethod_Type

  类方法对象的类型。它与 Python 层面的 `classmethod` 是相同的对象。

PyTypeObject PyClassMethodDescr_Type
  属于 稳定 ABI.

  The type object for C-level class method descriptor objects. This is the type of the descriptors created for `classmethod()` defined in C extension types, and corresponds to `types.ClassMethodDescriptorType` objects in Python.

PyObject *PyClassMethod_New(PyObject *callable)

  新建一个包裹 callable 的 `classmethod` 对象。callable 必须是一个可调用对象，并且不可为 `NULL` 值。

  成功时，此函数将返回一个指向新类方法描述器的 strong reference。失败时，此函数将返回 `NULL` 并设置一个异常。

PyTypeObject PyStaticMethod_Type

  静态方法对象的类型。它与 Python 层面的 `staticmethod` 是相同的对象。

PyObject *PyStaticMethod_New(PyObject *callable)

  新建一个包裹 callable 的 `staticmethod` 对象。callable 必须是一个可调用对象，并且不可为 `NULL` 值。

  成功时，此函数将返回一个指向新静态方法描述器的 strong reference。失败时，此函数将返回 `NULL` 并设置一个异常。