Type Objects

Quick Reference

tp slots

• tp_name
• tp_basicsize
• tp_itemsize
• tp_dealloc
• tp_vectorcall_offset
• tp_as_async
• tp_repr
• tp_as_number
• tp_as_sequence
• tp_as_mapping
• tp_hash
• tp_call
• tp_str
• tp_getattro
• tp_setattro
• tp_as_buffer
• tp_flags
• tp_doc
• tp_traverse
• tp_clear
• tp_richcompare
• tp_weaklistoffset
• tp_iter
• tp_iternext
• tp_methods
• tp_members
• tp_getset
• tp_base
• tp_dict
• tp_descr_get
• tp_descr_set
• tp_dictoffset
• tp_init
• tp_alloc
• tp_new
• tp_free
• tp_is_gc
• <tp_bases>
• <tp_mro>
• tp_finalize
• tp_vectorcall

sub-slots

• am_await

• am_aiter

• am_anext

• am_send

• nb_add

• nb_inplace_add

• mp_length

• mp_subscript

• mp_ass_subscript

• sq_length

• sq_concat

• sq_repeat

• sq_item

• sq_ass_item

• sq_contains

• sq_inplace_concat

• sq_inplace_repeat

• bf_getbuffer

• bf_releasebuffer

slot typedefs

• allocfunc
• destructor
• freefunc
• traverseproc
• newfunc
• initproc
• reprfunc
• getattrfunc
• setattrfunc
• getattrofunc
• setattrofunc
• descrgetfunc
• descrsetfunc
• hashfunc
• richcmpfunc
• getiterfunc
• iternextfunc
• lenfunc
• getbufferproc
• releasebufferproc
• inquiry
• unaryfunc
• binaryfunc
• ternaryfunc
• ssizeargfunc
• ssizeobjargproc
• objobjproc
• objobjargproc

PyTypeObject Definition

typedef struct _typeobject {
    PyObject_VAR_HEAD
    const char *tp_name; /* For printing, in format "<module>.<name>" */
    Py_ssize_t tp_basicsize, tp_itemsize; /* For allocation */

    /* Methods to implement standard operations */

    destructor tp_dealloc;
    Py_ssize_t tp_vectorcall_offset;
    getattrfunc tp_getattr;
    setattrfunc tp_setattr;
    PyAsyncMethods *tp_as_async; /* formerly known as tp_compare (Python 2)
                                    or tp_reserved (Python 3) */
    reprfunc tp_repr;

    /* Method suites for standard classes */

    PyNumberMethods *tp_as_number;
    PySequenceMethods *tp_as_sequence;
    PyMappingMethods *tp_as_mapping;

    /* More standard operations (here for binary compatibility) */

    hashfunc tp_hash;
    ternaryfunc tp_call;
    reprfunc tp_str;
    getattrofunc tp_getattro;
    setattrofunc tp_setattro;

    /* Functions to access object as input/output buffer */
    PyBufferProcs *tp_as_buffer;

    /* Flags to define presence of optional/expanded features */
    unsigned long tp_flags;

    const char *tp_doc; /* Documentation string */

    /* Assigned meaning in release 2.0 */
    /* call function for all accessible objects */
    traverseproc tp_traverse;

    /* delete references to contained objects */
    inquiry tp_clear;

    /* Assigned meaning in release 2.1 */
    /* rich comparisons */
    richcmpfunc tp_richcompare;

    /* weak reference enabler */
    Py_ssize_t tp_weaklistoffset;

    /* Iterators */
    getiterfunc tp_iter;
    iternextfunc tp_iternext;

    /* Attribute descriptor and subclassing stuff */
    struct PyMethodDef *tp_methods;
    struct PyMemberDef *tp_members;
    struct PyGetSetDef *tp_getset;
    // Strong reference on a heap type, borrowed reference on a static type
    struct _typeobject *tp_base;
    PyObject *tp_dict;
    descrgetfunc tp_descr_get;
    descrsetfunc tp_descr_set;
    Py_ssize_t tp_dictoffset;
    initproc tp_init;
    allocfunc tp_alloc;
    newfunc tp_new;
    freefunc tp_free; /* Low-level free-memory routine */
    inquiry tp_is_gc; /* For PyObject_IS_GC */
    PyObject *tp_bases;
    PyObject *tp_mro; /* method resolution order */
    PyObject *tp_cache;
    PyObject *tp_subclasses;
    PyObject *tp_weaklist;
    destructor tp_del;

    /* Type attribute cache version tag. Added in version 2.6 */
    unsigned int tp_version_tag;

    destructor tp_finalize;
    vectorcallfunc tp_vectorcall;
} PyTypeObject;

PyObject Slots

• Py_ssize_t PyObject.ob_refcnt
• PyTypeObject *PyObject.ob_type

PyVarObject Slots

• Py_ssize_t PyVarObject.ob_size

PyTypeObject Slots

• const char *PyTypeObject.tp_name
• Py_ssize_t PyTypeObject.tp_basicsize
• Py_ssize_t PyTypeObject.tp_itemsize
• destructor PyTypeObject.tp_dealloc

static void foo_dealloc(foo_object *self) {
    PyObject_GC_UnTrack(self);
    Py_CLEAR(self->ref);
    Py_TYPE(self)->tp_free((PyObject *)self);
}

• Py_ssize_t PyTypeObject.tp_vectorcall_offset
• reprfunc PyTypeObject.tp_repr
• PyNumberMethods *PyTypeObject.tp_as_number
• PySequenceMethods *PyTypeObject.tp_as_sequence
• PyMappingMethods *PyTypeObject.tp_as_mapping
• hashfunc PyTypeObject.tp_hash
• ternaryfunc PyTypeObject.tp_call
• reprfunc PyTypeObject.tp_str
• getattrofunc PyTypeObject.tp_getattro
• setattrofunc PyTypeObject.tp_setattro
• PyBufferProcs *PyTypeObject.tp_as_buffer
• unsigned long PyTypeObject.tp_flags
• const char *PyTypeObject.tp_doc
• traverseproc PyTypeObject.tp_traverse
• inquiry PyTypeObject.tp_clear
• richcmpfunc PyTypeObject.tp_richcompare
• Py_ssize_t PyTypeObject.tp_weaklistoffset
• getiterfunc PyTypeObject.tp_iter
• iternextfunc PyTypeObject.tp_iternext
• struct PyMethodDef *PyTypeObject.tp_methods
• struct PyMemberDef *PyTypeObject.tp_members
• struct PyGetSetDef *PyTypeObject.tp_getset
• PyTypeObject *PyTypeObject.tp_base
• PyObject *PyTypeObject.tp_dict
• descrgetfunc PyTypeObject.tp_descr_get
• descrsetfunc PyTypeObject.tp_descr_set
• Py_ssize_t PyTypeObject.tp_dictoffset
• initproc PyTypeObject.tp_init
• allocfunc PyTypeObject.tp_alloc
• newfunc PyTypeObject.tp_new
• freefunc PyTypeObject.tp_free
• PyObject *PyTypeObject.tp_bases
• PyObject *PyTypeObject.tp_mro
• PyObject *PyTypeObject.tp_subclasses

Static Types

Traditionally, types defined in C code are static, that is, a static PyTypeObject structure is defined directly in code and initialized using PyType_Ready()

• Static types are limited to one base, i.e. they cannot use multiple inheritance.
• Static type objects (but not necessarily their instances) are immutable. It is not possible to add or modify the type object’s attributes from Python.
• Static type objects are shared across sub-interpreters, so they should not include any subinterpreter-specific state.

Heap Types

An alternative to static types is heap-allocated types, or heap types for short, which correspond closely to classes created by Python’s class statement. Heap types have the Py_TPFLAGS_HEAPTYPE flag set.

This is done by filling a PyType_Spec structure and calling PyType_FromSpec(), PyType_FromSpecWithBases(), or PyType_FromModuleAndSpec().

Number Object Structures

type PyNumberMethods

typedef struct {
     binaryfunc nb_add;
     binaryfunc nb_subtract;
     binaryfunc nb_multiply;
     binaryfunc nb_remainder;
     binaryfunc nb_divmod;
     ternaryfunc nb_power;
     unaryfunc nb_negative;
     unaryfunc nb_positive;
     unaryfunc nb_absolute;
     inquiry nb_bool;
     unaryfunc nb_invert;
     binaryfunc nb_lshift;
     binaryfunc nb_rshift;
     binaryfunc nb_and;
     binaryfunc nb_xor;
     binaryfunc nb_or;
     unaryfunc nb_int;
     void *nb_reserved;
     unaryfunc nb_float;

     binaryfunc nb_inplace_add;
     binaryfunc nb_inplace_subtract;
     binaryfunc nb_inplace_multiply;
     binaryfunc nb_inplace_remainder;
     ternaryfunc nb_inplace_power;
     binaryfunc nb_inplace_lshift;
     binaryfunc nb_inplace_rshift;
     binaryfunc nb_inplace_and;
     binaryfunc nb_inplace_xor;
     binaryfunc nb_inplace_or;

     binaryfunc nb_floor_divide;
     binaryfunc nb_true_divide;
     binaryfunc nb_inplace_floor_divide;
     binaryfunc nb_inplace_true_divide;

     unaryfunc nb_index;

     binaryfunc nb_matrix_multiply;
     binaryfunc nb_inplace_matrix_multiply;
} PyNumberMethods;

Mapping Object Structures

• type PyMappingMethods
• lenfunc PyMappingMethods.mp_length
• binaryfunc PyMappingMethods.mp_subscript
• objobjargproc PyMappingMethods.mp_ass_subscript

Sequence Object Structures

• type PySequenceMethods

Buffer Object Structures

• type PyBufferProcs

Async Object Structures

• type PyAsyncMethods

Slot Type typedefs

• typedef PyObject *(*allocfunc)(PyTypeObject *cls, Py_ssize_t nitems)
• typedef void (*destructor)(PyObject*)
• typedef void (*freefunc)(void*)
• typedef PyObject *(*newfunc)(PyObject*, PyObject*, PyObject*)
• typedef int (*initproc)(PyObject*, PyObject*, PyObject*)
• typedef PyObject *(*reprfunc)(PyObject*)
• typedef PyObject *(*getattrfunc)(PyObject *self, char *attr)
• typedef int (*setattrfunc)(PyObject *self, char *attr, PyObject *value)
• typedef PyObject *(*getattrofunc)(PyObject *self, PyObject *attr)
• typedef int (*setattrofunc)(PyObject *self, PyObject *attr, PyObject *value)
• typedef PyObject *(*descrgetfunc)(PyObject*, PyObject*, PyObject*)
• typedef int (*descrsetfunc)(PyObject*, PyObject*, PyObject*)
• typedef Py_hash_t (*hashfunc)(PyObject*)
• typedef PyObject *(*richcmpfunc)(PyObject*, PyObject*, int)
• typedef PyObject *(*getiterfunc)(PyObject*)
• typedef PyObject *(*iternextfunc)(PyObject*)
• typedef Py_ssize_t (*lenfunc)(PyObject*)
• typedef int (*getbufferproc)(PyObject*, Py_buffer*, int)
• typedef void (*releasebufferproc)(PyObject*, Py_buffer*)
• typedef PyObject *(*unaryfunc)(PyObject*)
• typedef PyObject *(*binaryfunc)(PyObject*, PyObject*)
• typedef PySendResult (*sendfunc)(PyObject*, PyObject*, PyObject**)
• typedef PyObject *(*ternaryfunc)(PyObject*, PyObject*, PyObject*)
• typedef PyObject *(*ssizeargfunc)(PyObject*, Py_ssize_t)
• typedef int (*ssizeobjargproc)(PyObject*, Py_ssize_t, PyObject*)
• typedef int (*objobjproc)(PyObject*, PyObject*)
• typedef int (*objobjargproc)(PyObject*, PyObject*, PyObject*)