型オブジェクト
**************

type PyTypeObject
    * Part of the Limited API (as an opaque struct).*

   組み込み型を記述する際に用いられる、オブジェクトを表す C 構造体です
   。

PyTypeObject PyType_Type
    * Part of the Stable ABI.*

   型オブジェクト自身の型オブジェクトです。Python レイヤにおける
   "type" と同じオブジェクトです。

int PyType_Check(PyObject *o)

   Return non-zero if the object *o* is a type object, including
   instances of types derived from the standard type object.  Return 0
   in all other cases. This function always succeeds.

int PyType_CheckExact(PyObject *o)

   Return non-zero if the object *o* is a type object, but not a
   subtype of the standard type object.  Return 0 in all other cases.
   This function always succeeds.

unsigned int PyType_ClearCache()
    * Part of the Stable ABI.*

   内部の検索キャッシュをクリアします。現在のバージョンタグを返します
   。

unsigned long PyType_GetFlags(PyTypeObject *type)
    * Part of the Stable ABI.*

   *type* のメンバーである "tp_flags" を返します。この関数は基本的に
   "Py_LIMITED_API" を定義して使うことを想定しています。それぞれのフラ
   グはpythonの異なるリリースで安定していることが保証されていますが、
   "tp_flags" 自体は限定されたAPIの一部ではありません。

   バージョン 3.2 で追加.

   バージョン 3.4 で変更: 返り値の型が "long" ではなく "unsigned long"
   になりました。

void PyType_Modified(PyTypeObject *type)
    * Part of the Stable ABI.*

   内部の検索キャッシュを、その type とすべてのサブタイプに対して無効
   にします。この関数は type の属性や基底クラス列を変更したあとに手動
   で呼び出さなければなりません。

int PyType_HasFeature(PyTypeObject *o, int feature)

   Return non-zero if the type object *o* sets the feature *feature*.
   Type features are denoted by single bit flags.

int PyType_IS_GC(PyTypeObject *o)

   型オブジェクトが *o* が循環参照検出をサポートしている場合に真を返し
   ます; この関数は型機能フラグ "Py_TPFLAGS_HAVE_GC" の設定状態をチェ
   ックします。

int PyType_IsSubtype(PyTypeObject *a, PyTypeObject *b)
    * Part of the Stable ABI.*

   *a* が *b* のサブタイプの場合に真を返します。

   この関数は実際のサブクラスをチェックするだけです。つまり、
   "__subclasscheck__()" は *b* に対し呼ばれません。 "issubclass()" と
   同じチェックをするには "PyObject_IsSubclass()" を呼んでください。

PyObject *PyType_GenericAlloc(PyTypeObject *type, Py_ssize_t nitems)
    *Return value: New reference.** Part of the Stable ABI.*

   型オブジェクトの "tp_alloc" に対するジェネリックハンドラです。
   Python のデフォルトのメモリアロケートメカニズムを使って新しいインス
   タンスをアロケートし、すべての内容を "NULL" で初期化します。

PyObject *PyType_GenericNew(PyTypeObject *type, PyObject *args, PyObject *kwds)
    *Return value: New reference.** Part of the Stable ABI.*

   型オブジェクトの "tp_new" に対するジェネリックハンドラです。型の
   "tp_alloc" スロットを使って新しいインスタンスを作成します。

int PyType_Ready(PyTypeObject *type)
    * Part of the Stable ABI.*

   型オブジェクトのファイナライズを行います。この関数は全てのオブジェ
   クトで初期化を完了するために呼び出されなくてはなりません。この関数
   は、基底クラス型から継承したスロットを型オブジェクトに追加する役割
   があります。成功した場合には "0" を返し、エラーの場合には "-1" を返
   して例外情報を設定します。

   注釈:

     If some of the base classes implements the GC protocol and the
     provided type does not include the "Py_TPFLAGS_HAVE_GC" in its
     flags, then the GC protocol will be automatically implemented
     from its parents. On the contrary, if the type being created does
     include "Py_TPFLAGS_HAVE_GC" in its flags then it **must**
     implement the GC protocol itself by at least implementing the
     "tp_traverse" handle.

void *PyType_GetSlot(PyTypeObject *type, int slot)
    * Part of the Stable ABI since version 3.4.*

   与えられたスロットに格納されている関数ポインタを返します。返り値が
   "NULL" の場合は、スロットが "NULL" か、関数が不正な引数で呼ばれたこ
   とを示します。通常、呼び出し側は返り値のポインタを適切な関数型にキ
   ャストします。

   See "PyType_Slot.slot" for possible values of the *slot* argument.

   バージョン 3.4 で追加.

   バージョン 3.10 で変更: "PyType_GetSlot()" can now accept all
   types. Previously, it was limited to heap types.

PyObject *PyType_GetModule(PyTypeObject *type)
    * Part of the Stable ABI since version 3.10.*

   Return the module object associated with the given type when the
   type was created using "PyType_FromModuleAndSpec()".

   If no module is associated with the given type, sets "TypeError"
   and returns "NULL".

   This function is usually used to get the module in which a method
   is defined. Note that in such a method,
   "PyType_GetModule(Py_TYPE(self))" may not return the intended
   result. "Py_TYPE(self)" may be a *subclass* of the intended class,
   and subclasses are not necessarily defined in the same module as
   their superclass. See "PyCMethod" to get the class that defines the
   method.

   バージョン 3.9 で追加.

void *PyType_GetModuleState(PyTypeObject *type)
    * Part of the Stable ABI since version 3.10.*

   Return the state of the module object associated with the given
   type. This is a shortcut for calling "PyModule_GetState()" on the
   result of "PyType_GetModule()".

   If no module is associated with the given type, sets "TypeError"
   and returns "NULL".

   If the *type* has an associated module but its state is "NULL",
   returns "NULL" without setting an exception.

   バージョン 3.9 で追加.


Creating Heap-Allocated Types
=============================

The following functions and structs are used to create heap types.

PyObject *PyType_FromModuleAndSpec(PyObject *module, PyType_Spec *spec, PyObject *bases)
    *Return value: New reference.** Part of the Stable ABI since
   version 3.10.*

   Creates and returns a heap type from the *spec*
   ("Py_TPFLAGS_HEAPTYPE").

   The *bases* argument can be used to specify base classes; it can
   either be only one class or a tuple of classes. If *bases* is
   "NULL", the *Py_tp_bases* slot is used instead. If that also is
   "NULL", the *Py_tp_base* slot is used instead. If that also is
   "NULL", the new type derives from "object".

   The *module* argument can be used to record the module in which the
   new class is defined. It must be a module object or "NULL". If not
   "NULL", the module is associated with the new type and can later be
   retrieved with "PyType_GetModule()". The associated module is not
   inherited by subclasses; it must be specified for each class
   individually.

   This function calls "PyType_Ready()" on the new type.

   バージョン 3.9 で追加.

   バージョン 3.10 で変更: The function now accepts a single class as
   the *bases* argument and "NULL" as the "tp_doc" slot.

PyObject *PyType_FromSpecWithBases(PyType_Spec *spec, PyObject *bases)
    *Return value: New reference.** Part of the Stable ABI since
   version 3.3.*

   Equivalent to "PyType_FromModuleAndSpec(NULL, spec, bases)".

   バージョン 3.3 で追加.

PyObject *PyType_FromSpec(PyType_Spec *spec)
    *Return value: New reference.** Part of the Stable ABI.*

   Equivalent to "PyType_FromSpecWithBases(spec, NULL)".

type PyType_Spec
    * Part of the Stable ABI (including all members).*

   Structure defining a type's behavior.

   const char *PyType_Spec.name

      Name of the type, used to set "PyTypeObject.tp_name".

   int PyType_Spec.basicsize

   int PyType_Spec.itemsize

      Size of the instance in bytes, used to set
      "PyTypeObject.tp_basicsize" and "PyTypeObject.tp_itemsize".

   int PyType_Spec.flags

      Type flags, used to set "PyTypeObject.tp_flags".

      If the "Py_TPFLAGS_HEAPTYPE" flag is not set,
      "PyType_FromSpecWithBases()" sets it automatically.

   PyType_Slot *PyType_Spec.slots

      Array of "PyType_Slot" structures. Terminated by the special
      slot value "{0, NULL}".

type PyType_Slot
    * Part of the Stable ABI (including all members).*

   Structure defining optional functionality of a type, containing a
   slot ID and a value pointer.

   int PyType_Slot.slot

         A slot ID.

         Slot IDs are named like the field names of the structures
         "PyTypeObject", "PyNumberMethods", "PySequenceMethods",
         "PyMappingMethods" and "PyAsyncMethods" with an added "Py_"
         prefix. For example, use:

         * "Py_tp_dealloc" to set "PyTypeObject.tp_dealloc"

         * "Py_nb_add" to set "PyNumberMethods.nb_add"

         * "Py_sq_length" to set "PySequenceMethods.sq_length"

         The following fields cannot be set at all using "PyType_Spec"
         and "PyType_Slot":

         * "tp_dict"

         * "tp_mro"

         * "tp_cache"

         * "tp_subclasses"

         * "tp_weaklist"

         * "tp_vectorcall"

         * "tp_weaklistoffset" (see PyMemberDef)

         * "tp_dictoffset" (see PyMemberDef)

         * "tp_vectorcall_offset" (see PyMemberDef)

         The following fields cannot be set using "PyType_Spec" and
         "PyType_Slot" under the limited API:

         * "bf_getbuffer"

         * "bf_releasebuffer"

         Setting "Py_tp_bases" or "Py_tp_base" may be problematic on
         some platforms. To avoid issues, use the *bases* argument of
         "PyType_FromSpecWithBases()" instead.

      バージョン 3.9 で変更: Slots in "PyBufferProcs" may be set in
      the unlimited API.

   void *PyType_Slot.pfunc

      The desired value of the slot. In most cases, this is a pointer
      to a function.

      Slots other than "Py_tp_doc" may not be "NULL".
