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# Type Objects

`PyTypeObject`

  The C structure of the objects used to describe built-in types.

PyObject* `PyType_Type`

  This is the type object for type objects; it is the same object as `type` and `types.TypeType` in the Python layer.

int `PyType_Check`(PyObject *o)

  Return true if the object o is a type object, including instances of types derived from the standard type object. Return false in all other cases.

int `PyType_CheckExact`(PyObject *o)

  Return true if the object o is a type object, but not a subtype of the standard type object. Return false in all other cases.

  New in version 2.2.

unsigned int `PyType_ClearCache`()

  Clear the internal lookup cache. Return the current version tag.

  New in version 2.6.

void `PyType_Modified`(PyTypeObject *type)

  Invalidate the internal lookup cache for the type and all of its subtypes. This function must be called after any manual modification of the attributes or base classes of the type.

  New in version 2.6.

int `PyType_HasFeature`(PyObject *o, int feature)

  Return true if the type object o sets the feature feature. Type features are denoted by single bit flags.

int `PyType_IS_GC`(PyObject *o)

  Return true if the type object includes support for the cycle detector; this tests the type flag `Py_TPFLAGS_HAVE_GC`.

  New in version 2.0.

int `PyType_IsSubtype`(PyTypeObject *a, PyTypeObject *b)

  Return true if a is a subtype of b.

  New in version 2.2.

  This function only checks for actual subtypes, which means that `__subclasscheck__()` is not called on b. Call `PyObject_IsSubclass()` to do the same check that `issubclass()` would do.

PyObject* `PyType_GenericAlloc`(PyTypeObject *type, Py_ssize_t nitems)
  Return value: New reference.

  New in version 2.2.

  Changed in version 2.5: This function used an `int` type for nitems. This might require changes in your code for properly supporting 64-bit systems.

PyObject* `PyType_GenericNew`(PyTypeObject *type, PyObject *args, PyObject *kwds)
  Return value: New reference.

  New in version 2.2.

int `PyType_Ready`(PyTypeObject *type)

  Finalize a type object. This should be called on all type objects to finish their initialization. This function is responsible for adding inherited slots from a type’s base class. Return `0` on success, or return `-1` and sets an exception on error.

  New in version 2.2.