All integers are implemented as “long” integer objects of arbitrary size.

PyLongObject

This subtype of PyObject represents a Python integer object.

PyTypeObject PyLong_Type

This instance of PyTypeObject represents the Python integer type. This is the same object as int in the Python layer.

int PyLong_Check(PyObject *p)

Return true if its argument is a PyLongObject or a subtype of PyLongObject.

int PyLong_CheckExact(PyObject *p)

Return true if its argument is a PyLongObject, but not a subtype of PyLongObject.

PyObject* PyLong_FromLong(long v)
Return value: New reference.

Return a new PyLongObject object from v, or NULL on failure.

The current implementation keeps an array of integer objects for all integers between -5 and 256, when you create an int in that range you actually just get back a reference to the existing object. So it should be possible to change the value of 1. I suspect the behaviour of Python in this case is undefined. :-)

PyObject* PyLong_FromUnsignedLong(unsigned long v)
Return value: New reference.

Return a new PyLongObject object from a C unsigned long, or NULL on failure.

PyObject* PyLong_FromSsize_t(Py_ssize_t v)

Return a new PyLongObject object from a C Py_ssize_t, or NULL on failure.

PyObject* PyLong_FromSize_t(size_t v)

Return a new PyLongObject object from a C size_t, or NULL on failure.

PyObject* PyLong_FromLongLong(PY_LONG_LONG v)
Return value: New reference.

Return a new PyLongObject object from a C long long, or NULL on failure.

PyObject* PyLong_FromUnsignedLongLong(unsigned PY_LONG_LONG v)
Return value: New reference.

Return a new PyLongObject object from a C unsigned long long, or NULL on failure.

PyObject* PyLong_FromDouble(double v)
Return value: New reference.

Return a new PyLongObject object from the integer part of v, or NULL on failure.

PyObject* PyLong_FromString(const char *str, char **pend, int base)
Return value: New reference.

Return a new PyLongObject based on the string value in str, which is interpreted according to the radix in base. If pend is non-NULL, *pend will point to the first character in str which follows the representation of the number. If base is 0, str is interpreted using the Integer literals definition; in this case, leading zeros in a non-zero decimal number raises a ValueError. If base is not 0, it must be between 2 and 36, inclusive. Leading spaces and single underscores after a base specifier and between digits are ignored. If there are no digits, ValueError will be raised.

PyObject* PyLong_FromUnicode(Py_UNICODE *u, Py_ssize_t length, int base)
Return value: New reference.

Convert a sequence of Unicode digits to a Python integer value. The Unicode string is first encoded to a byte string using PyUnicode_EncodeDecimal() and then converted using PyLong_FromString().

Deprecated since version 3.3, will be removed in version 4.0: Part of the old-style Py_UNICODE API; please migrate to using PyLong_FromUnicodeObject().

PyObject* PyLong_FromUnicodeObject(PyObject *u, int base)

Convert a sequence of Unicode digits in the string u to a Python integer value. The Unicode string is first encoded to a byte string using PyUnicode_EncodeDecimal() and then converted using PyLong_FromString().

New in version 3.3.

PyObject* PyLong_FromVoidPtr(void *p)
Return value: New reference.

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)

Return a C long representation of obj. If obj is not an instance of PyLongObject, first call its __int__() method (if present) to convert it to a PyLongObject.

Raise OverflowError if the value of obj is out of range for a long.

long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow)

Return a C long representation of obj. If obj is not an instance of PyLongObject, first call its __int__() method (if present) to convert it to a PyLongObject.

If the value of obj is greater than LONG_MAX or less than LONG_MIN, set *overflow to 1 or -1, respectively, and return -1; otherwise, set *overflow to 0. If any other exception occurs set *overflow to 0 and return -1 as usual.

PY_LONG_LONG PyLong_AsLongLong(PyObject *obj)

Return a C long long representation of obj. If obj is not an instance of PyLongObject, first call its __int__() method (if present) to convert it to a PyLongObject.

Raise OverflowError if the value of obj is out of range for a long.

PY_LONG_LONG PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow)

Return a C long long representation of obj. If obj is not an instance of PyLongObject, first call its __int__() method (if present) to convert it to a PyLongObject.

If the value of obj is greater than PY_LLONG_MAX or less than PY_LLONG_MIN, set *overflow to 1 or -1, respectively, and return -1; otherwise, set *overflow to 0. If any other exception occurs set *overflow to 0 and return -1 as usual.

New in version 3.2.

Py_ssize_t PyLong_AsSsize_t(PyObject *pylong)

Return a C Py_ssize_t representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for a Py_ssize_t.

unsigned long PyLong_AsUnsignedLong(PyObject *pylong)

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.

size_t PyLong_AsSize_t(PyObject *pylong)

Return a C size_t representation of pylong. pylong must be an instance of PyLongObject.

Raise OverflowError if the value of pylong is out of range for a size_t.

unsigned PY_LONG_LONG PyLong_AsUnsignedLongLong(PyObject *pylong)

Return a C unsigned PY_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 PY_LONG_LONG.

Changed in version 3.1: A negative pylong now raises OverflowError, not TypeError.

unsigned long PyLong_AsUnsignedLongMask(PyObject *obj)

Return a C unsigned long representation of obj. If obj is not an instance of PyLongObject, first call its __int__() method (if present) to convert it to a PyLongObject.

If the value of obj is out of range for an unsigned long, return the reduction of that value modulo ULONG_MAX + 1.

unsigned PY_LONG_LONG PyLong_AsUnsignedLongLongMask(PyObject *obj)

Return a C unsigned long long representation of obj. If obj is not an instance of PyLongObject, first call its __int__() method (if present) to convert it to a PyLongObject.

If the value of obj is out of range for an unsigned long long, return the reduction of that value modulo PY_ULLONG_MAX + 1.

double PyLong_AsDouble(PyObject *pylong)

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.

void* PyLong_AsVoidPtr(PyObject *pylong)

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 with PyLong_FromVoidPtr().