Integer Objects¶
All integers are implemented as “long” integer objects of arbitrary size.
On error, most PyLong_As*
APIs return (return type)1
which cannot be
distinguished from a number. Use PyErr_Occurred()
to disambiguate.

type PyLongObject¶
 Part of the Limited API (as an opaque struct).
This subtype of
PyObject
represents a Python integer object.

PyTypeObject PyLong_Type¶
 Part of the Stable ABI.
This instance of
PyTypeObject
represents the Python integer type. This is the same object asint
in the Python layer.

int PyLong_Check(PyObject *p)¶
Return true if its argument is a
PyLongObject
or a subtype ofPyLongObject
. This function always succeeds.

int PyLong_CheckExact(PyObject *p)¶
Return true if its argument is a
PyLongObject
, but not a subtype ofPyLongObject
. This function always succeeds.

PyObject *PyLong_FromLong(long v)¶
 Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject
object from v, orNULL
on failure.The current implementation keeps an array of integer objects for all integers between
5
and256
. When you create an int in that range you actually just get back a reference to the existing object.

PyObject *PyLong_FromUnsignedLong(unsigned long v)¶
 Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject
object from a C unsigned long, orNULL
on failure.

PyObject *PyLong_FromSsize_t(Py_ssize_t v)¶
 Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject
object from a CPy_ssize_t
, orNULL
on failure.

PyObject *PyLong_FromSize_t(size_t v)¶
 Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject
object from a Csize_t
, orNULL
on failure.

PyObject *PyLong_FromLongLong(long long v)¶
 Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject
object from a C long long, orNULL
on failure.

PyObject *PyLong_FromUnsignedLongLong(unsigned long long v)¶
 Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject
object from a C unsigned long long, orNULL
on failure.

PyObject *PyLong_FromDouble(double v)¶
 Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject
object from the integer part of v, orNULL
on failure.

PyObject *PyLong_FromString(const char *str, char **pend, int base)¶
 Return value: New reference. Part of the Stable ABI.
Return a new
PyLongObject
based on the string value in str, which is interpreted according to the radix in base, orNULL
on failure. If pend is nonNULL
, *pend will point to the end of str on success or to the first character that could not be processed on error. If base is0
, str is interpreted using the Integer literals definition; in this case, leading zeros in a nonzero decimal number raises aValueError
. If base is not0
, it must be between2
and36
, inclusive. Leading and trailing whitespace and single underscores after a base specifier and between digits are ignored. If there are no digits or str is not NULLterminated following the digits and trailing whitespace,ValueError
will be raised.See also
Python methods
int.to_bytes()
andint.from_bytes()
to convert aPyLongObject
to/from an array of bytes in base256
. You can call those from C usingPyObject_CallMethod()
.

PyObject *PyLong_FromUnicodeObject(PyObject *u, int base)¶
 Return value: New reference.
Convert a sequence of Unicode digits in the string u to a Python integer value.
Added in version 3.3.

PyObject *PyLong_FromVoidPtr(void *p)¶
 Return value: New reference. Part of the Stable ABI.
Create a Python integer from the pointer p. The pointer value can be retrieved from the resulting value using
PyLong_AsVoidPtr()
.

long PyLong_AsLong(PyObject *obj)¶
 Part of the Stable ABI.
Return a C long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.Raise
OverflowError
if the value of obj is out of range for a long.Returns
1
on error. UsePyErr_Occurred()
to disambiguate.Changed in version 3.8: Use
__index__()
if available.Changed in version 3.10: This function will no longer use
__int__()
.

long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow)¶
 Part of the Stable ABI.
Return a C long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If the value of obj is greater than
LONG_MAX
or less thanLONG_MIN
, set *overflow to1
or1
, respectively, and return1
; otherwise, set *overflow to0
. If any other exception occurs set *overflow to0
and return1
as usual.Returns
1
on error. UsePyErr_Occurred()
to disambiguate.Changed in version 3.8: Use
__index__()
if available.Changed in version 3.10: This function will no longer use
__int__()
.

long long PyLong_AsLongLong(PyObject *obj)¶
 Part of the Stable ABI.
Return a C long long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.Raise
OverflowError
if the value of obj is out of range for a long long.Returns
1
on error. UsePyErr_Occurred()
to disambiguate.Changed in version 3.8: Use
__index__()
if available.Changed in version 3.10: This function will no longer use
__int__()
.

long long PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow)¶
 Part of the Stable ABI.
Return a C long long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If the value of obj is greater than
LLONG_MAX
or less thanLLONG_MIN
, set *overflow to1
or1
, respectively, and return1
; otherwise, set *overflow to0
. If any other exception occurs set *overflow to0
and return1
as usual.Returns
1
on error. UsePyErr_Occurred()
to disambiguate.Added in version 3.2.
Changed in version 3.8: Use
__index__()
if available.Changed in version 3.10: This function will no longer use
__int__()
.

Py_ssize_t PyLong_AsSsize_t(PyObject *pylong)¶
 Part of the Stable ABI.
Return a C
Py_ssize_t
representation of pylong. pylong must be an instance ofPyLongObject
.Raise
OverflowError
if the value of pylong is out of range for aPy_ssize_t
.Returns
1
on error. UsePyErr_Occurred()
to disambiguate.

unsigned long PyLong_AsUnsignedLong(PyObject *pylong)¶
 Part of the Stable ABI.
Return a C unsigned long representation of pylong. pylong must be an instance of
PyLongObject
.Raise
OverflowError
if the value of pylong is out of range for a unsigned long.Returns
(unsigned long)1
on error. UsePyErr_Occurred()
to disambiguate.

size_t PyLong_AsSize_t(PyObject *pylong)¶
 Part of the Stable ABI.
Return a C
size_t
representation of pylong. pylong must be an instance ofPyLongObject
.Raise
OverflowError
if the value of pylong is out of range for asize_t
.Returns
(size_t)1
on error. UsePyErr_Occurred()
to disambiguate.

unsigned long long PyLong_AsUnsignedLongLong(PyObject *pylong)¶
 Part of the Stable ABI.
Return a C unsigned long long representation of pylong. pylong must be an instance of
PyLongObject
.Raise
OverflowError
if the value of pylong is out of range for an unsigned long long.Returns
(unsigned long long)1
on error. UsePyErr_Occurred()
to disambiguate.Changed in version 3.1: A negative pylong now raises
OverflowError
, notTypeError
.

unsigned long PyLong_AsUnsignedLongMask(PyObject *obj)¶
 Part of the Stable ABI.
Return a C unsigned long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If the value of obj is out of range for an unsigned long, return the reduction of that value modulo
ULONG_MAX + 1
.Returns
(unsigned long)1
on error. UsePyErr_Occurred()
to disambiguate.Changed in version 3.8: Use
__index__()
if available.Changed in version 3.10: This function will no longer use
__int__()
.

unsigned long long PyLong_AsUnsignedLongLongMask(PyObject *obj)¶
 Part of the Stable ABI.
Return a C unsigned long long representation of obj. If obj is not an instance of
PyLongObject
, first call its__index__()
method (if present) to convert it to aPyLongObject
.If the value of obj is out of range for an unsigned long long, return the reduction of that value modulo
ULLONG_MAX + 1
.Returns
(unsigned long long)1
on error. UsePyErr_Occurred()
to disambiguate.Changed in version 3.8: Use
__index__()
if available.Changed in version 3.10: This function will no longer use
__int__()
.

double PyLong_AsDouble(PyObject *pylong)¶
 Part of the Stable ABI.
Return a C double representation of pylong. pylong must be an instance of
PyLongObject
.Raise
OverflowError
if the value of pylong is out of range for a double.Returns
1.0
on error. UsePyErr_Occurred()
to disambiguate.

void *PyLong_AsVoidPtr(PyObject *pylong)¶
 Part of the Stable ABI.
Convert a Python integer pylong to a C void pointer. If pylong cannot be converted, an
OverflowError
will be raised. This is only assured to produce a usable void pointer for values created withPyLong_FromVoidPtr()
.Returns
NULL
on error. UsePyErr_Occurred()
to disambiguate.

int PyUnstable_Long_IsCompact(const PyLongObject *op)¶
 This is Unstable API. It may change without warning in minor releases.
Return 1 if op is compact, 0 otherwise.
This function makes it possible for performancecritical code to implement a “fast path” for small integers. For compact values use
PyUnstable_Long_CompactValue()
; for others fall back to aPyLong_As*
function orcalling
int.to_bytes()
.The speedup is expected to be negligible for most users.
Exactly what values are considered compact is an implementation detail and is subject to change.

Py_ssize_t PyUnstable_Long_CompactValue(const PyLongObject *op)¶
 This is Unstable API. It may change without warning in minor releases.
If op is compact, as determined by
PyUnstable_Long_IsCompact()
, return its value.Otherwise, the return value is undefined.