# 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.

`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 value: New reference.

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

PyObject* `PyLong_FromSize_t`(size_t v)
  Return value: New reference.

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

PyObject* `PyLong_FromLongLong`(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 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 整型数字面值 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)
  Return value: New reference.

  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()`.

  3.3 新版功能.

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`.

  Returns `-1` on error. Use `PyErr_Occurred()` to disambiguate.

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.

  Returns `-1` on error. Use `PyErr_Occurred()` to disambiguate.

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`.

  Returns `-1` on error. Use `PyErr_Occurred()` to disambiguate.

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.

  Returns `-1` on error. Use `PyErr_Occurred()` to disambiguate.

  3.2 新版功能.

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`.

  Returns `-1` on error. Use `PyErr_Occurred()` to disambiguate.

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`.

  Returns `(unsigned long)-1` on error. Use `PyErr_Occurred()` to disambiguate.

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`.

  Returns `(size_t)-1` on error. Use `PyErr_Occurred()` to disambiguate.

unsigned long long `PyLong_AsUnsignedLongLong`(PyObject *pylong)

  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. Use `PyErr_Occurred()` to disambiguate.

  在 3.1 版更改: 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`.

  Returns `-1` on error. Use `PyErr_Occurred()` to disambiguate.

unsigned 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`.

  Returns `-1` on error. Use `PyErr_Occurred()` to disambiguate.

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`.

  Returns `-1.0` on error. Use `PyErr_Occurred()` to disambiguate.

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()`.

  Returns NULL on error. Use `PyErr_Occurred()` to disambiguate.