Descriptor Objects¶

“Descriptors” are objects that describe some attribute of an object. They are found in the dictionary of type objects.

PyTypeObject PyProperty_Type¶

Part of the Stable ABI.

The type object for the built-in descriptor types.

PyObject *PyDescr_NewGetSet(PyTypeObject *type, struct PyGetSetDef *getset)¶

Return value: New reference. Part of the Stable ABI.

Create a new get-set descriptor for extension type type from the PyGetSetDef structure getset.

Get-set descriptors expose attributes implemented by C getter and setter functions rather than stored directly in the instance. This is the same kind of descriptor created for entries in tp_getset, and it appears in Python as a types.GetSetDescriptorType object.

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)¶

Return value: New reference. Part of the Stable 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¶

Part of the Stable ABI.

The type object for member descriptor objects created from PyMemberDef structures. These descriptors expose fields of a C struct as attributes on a type, and correspond to types.MemberDescriptorType objects in Python.

PyTypeObject PyGetSetDescr_Type¶

Part of the Stable 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)¶

Return value: New reference. Part of the Stable 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¶

Part of the Stable 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)¶

Return value: New reference.

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¶

Part of the Stable ABI.

The type object for wrapper descriptor objects created by PyDescr_NewWrapper() and PyWrapper_New(). Wrapper descriptors are used internally to expose special methods implemented via wrapper structures, and appear in Python as types.WrapperDescriptorType objects.

PyObject *PyDescr_NewClassMethod(PyTypeObject *type, PyMethodDef *method)¶

Return value: New reference. Part of the Stable 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)¶

Return non-zero if the descriptor object descr describes a data attribute, or 0 if it describes a method. descr must be a descriptor object; there is no error checking.

PyObject *PyWrapper_New(PyObject *d, PyObject *self)¶

Return value: New reference. Part of the Stable 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.