.. highlight:: c .. _longobjects: Integer Objects --------------- .. index:: pair: object; long integer pair: object; integer 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 :c:func:`PyErr_Occurred` to disambiguate. .. c:type:: PyLongObject This subtype of :c:type:`PyObject` represents a Python integer object. .. c:var:: PyTypeObject PyLong_Type This instance of :c:type:`PyTypeObject` represents the Python integer type. This is the same object as :class:`int` in the Python layer. .. c:function:: int PyLong_Check(PyObject *p) Return true if its argument is a :c:type:`PyLongObject` or a subtype of :c:type:`PyLongObject`. This function always succeeds. .. c:function:: int PyLong_CheckExact(PyObject *p) Return true if its argument is a :c:type:`PyLongObject`, but not a subtype of :c:type:`PyLongObject`. This function always succeeds. .. c:function:: PyObject* PyLong_FromLong(long v) Return a new :c:type:`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. .. c:function:: PyObject* PyLong_FromUnsignedLong(unsigned long v) Return a new :c:type:`PyLongObject` object from a C :c:expr:`unsigned long`, or ``NULL`` on failure. .. c:function:: PyObject* PyLong_FromSsize_t(Py_ssize_t v) Return a new :c:type:`PyLongObject` object from a C :c:type:`Py_ssize_t`, or ``NULL`` on failure. .. c:function:: PyObject* PyLong_FromSize_t(size_t v) Return a new :c:type:`PyLongObject` object from a C :c:type:`size_t`, or ``NULL`` on failure. .. c:function:: PyObject* PyLong_FromLongLong(long long v) Return a new :c:type:`PyLongObject` object from a C :c:expr:`long long`, or ``NULL`` on failure. .. c:function:: PyObject* PyLong_FromUnsignedLongLong(unsigned long long v) Return a new :c:type:`PyLongObject` object from a C :c:expr:`unsigned long long`, or ``NULL`` on failure. .. c:function:: PyObject* PyLong_FromDouble(double v) Return a new :c:type:`PyLongObject` object from the integer part of *v*, or ``NULL`` on failure. .. c:function:: PyObject* PyLong_FromString(const char *str, char **pend, int base) Return a new :c:type:`PyLongObject` based on the string value in *str*, which is interpreted according to the radix in *base*, or ``NULL`` on failure. If *pend* is non-``NULL``, *\*pend* will point to the end of *str* on success or to the first character that could not be processed on error. If *base* is ``0``, *str* is interpreted using the :ref:`integers` definition; in this case, leading zeros in a non-zero decimal number raises a :exc:`ValueError`. If *base* is not ``0``, it must be between ``2`` and ``36``, 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 NULL-terminated following the digits and trailing whitespace, :exc:`ValueError` will be raised. .. seealso:: Python methods :meth:`int.to_bytes` and :meth:`int.from_bytes` to convert a :c:type:`PyLongObject` to/from an array of bytes in base ``256``. You can call those from C using :c:func:`PyObject_CallMethod`. .. c:function:: PyObject* PyLong_FromUnicodeObject(PyObject *u, int base) Convert a sequence of Unicode digits in the string *u* to a Python integer value. .. versionadded:: 3.3 .. c:function:: PyObject* PyLong_FromVoidPtr(void *p) Create a Python integer from the pointer *p*. The pointer value can be retrieved from the resulting value using :c:func:`PyLong_AsVoidPtr`. .. XXX alias PyLong_AS_LONG (for now) .. c:function:: long PyLong_AsLong(PyObject *obj) .. index:: single: LONG_MAX single: OverflowError (built-in exception) Return a C :c:expr:`long` representation of *obj*. If *obj* is not an instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method (if present) to convert it to a :c:type:`PyLongObject`. Raise :exc:`OverflowError` if the value of *obj* is out of range for a :c:expr:`long`. Returns ``-1`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. versionchanged:: 3.8 Use :meth:`~object.__index__` if available. .. versionchanged:: 3.10 This function will no longer use :meth:`~object.__int__`. .. c:function:: long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow) Return a C :c:expr:`long` representation of *obj*. If *obj* is not an instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method (if present) to convert it to a :c:type:`PyLongObject`. If the value of *obj* is greater than :c:macro:`LONG_MAX` or less than :c:macro:`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 :c:func:`PyErr_Occurred` to disambiguate. .. versionchanged:: 3.8 Use :meth:`~object.__index__` if available. .. versionchanged:: 3.10 This function will no longer use :meth:`~object.__int__`. .. c:function:: long long PyLong_AsLongLong(PyObject *obj) .. index:: single: OverflowError (built-in exception) Return a C :c:expr:`long long` representation of *obj*. If *obj* is not an instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method (if present) to convert it to a :c:type:`PyLongObject`. Raise :exc:`OverflowError` if the value of *obj* is out of range for a :c:expr:`long long`. Returns ``-1`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. versionchanged:: 3.8 Use :meth:`~object.__index__` if available. .. versionchanged:: 3.10 This function will no longer use :meth:`~object.__int__`. .. c:function:: long long PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow) Return a C :c:expr:`long long` representation of *obj*. If *obj* is not an instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method (if present) to convert it to a :c:type:`PyLongObject`. If the value of *obj* is greater than :c:macro:`LLONG_MAX` or less than :c:macro:`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 :c:func:`PyErr_Occurred` to disambiguate. .. versionadded:: 3.2 .. versionchanged:: 3.8 Use :meth:`~object.__index__` if available. .. versionchanged:: 3.10 This function will no longer use :meth:`~object.__int__`. .. c:function:: Py_ssize_t PyLong_AsSsize_t(PyObject *pylong) .. index:: single: PY_SSIZE_T_MAX single: OverflowError (built-in exception) Return a C :c:type:`Py_ssize_t` representation of *pylong*. *pylong* must be an instance of :c:type:`PyLongObject`. Raise :exc:`OverflowError` if the value of *pylong* is out of range for a :c:type:`Py_ssize_t`. Returns ``-1`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. c:function:: unsigned long PyLong_AsUnsignedLong(PyObject *pylong) .. index:: single: ULONG_MAX single: OverflowError (built-in exception) Return a C :c:expr:`unsigned long` representation of *pylong*. *pylong* must be an instance of :c:type:`PyLongObject`. Raise :exc:`OverflowError` if the value of *pylong* is out of range for a :c:expr:`unsigned long`. Returns ``(unsigned long)-1`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. c:function:: size_t PyLong_AsSize_t(PyObject *pylong) .. index:: single: SIZE_MAX single: OverflowError (built-in exception) Return a C :c:type:`size_t` representation of *pylong*. *pylong* must be an instance of :c:type:`PyLongObject`. Raise :exc:`OverflowError` if the value of *pylong* is out of range for a :c:type:`size_t`. Returns ``(size_t)-1`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. c:function:: unsigned long long PyLong_AsUnsignedLongLong(PyObject *pylong) .. index:: single: OverflowError (built-in exception) Return a C :c:expr:`unsigned long long` representation of *pylong*. *pylong* must be an instance of :c:type:`PyLongObject`. Raise :exc:`OverflowError` if the value of *pylong* is out of range for an :c:expr:`unsigned long long`. Returns ``(unsigned long long)-1`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. versionchanged:: 3.1 A negative *pylong* now raises :exc:`OverflowError`, not :exc:`TypeError`. .. c:function:: unsigned long PyLong_AsUnsignedLongMask(PyObject *obj) Return a C :c:expr:`unsigned long` representation of *obj*. If *obj* is not an instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method (if present) to convert it to a :c:type:`PyLongObject`. If the value of *obj* is out of range for an :c:expr:`unsigned long`, return the reduction of that value modulo ``ULONG_MAX + 1``. Returns ``(unsigned long)-1`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. versionchanged:: 3.8 Use :meth:`~object.__index__` if available. .. versionchanged:: 3.10 This function will no longer use :meth:`~object.__int__`. .. c:function:: unsigned long long PyLong_AsUnsignedLongLongMask(PyObject *obj) Return a C :c:expr:`unsigned long long` representation of *obj*. If *obj* is not an instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method (if present) to convert it to a :c:type:`PyLongObject`. If the value of *obj* is out of range for an :c:expr:`unsigned long long`, return the reduction of that value modulo ``ULLONG_MAX + 1``. Returns ``(unsigned long long)-1`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. versionchanged:: 3.8 Use :meth:`~object.__index__` if available. .. versionchanged:: 3.10 This function will no longer use :meth:`~object.__int__`. .. c:function:: double PyLong_AsDouble(PyObject *pylong) Return a C :c:expr:`double` representation of *pylong*. *pylong* must be an instance of :c:type:`PyLongObject`. Raise :exc:`OverflowError` if the value of *pylong* is out of range for a :c:expr:`double`. Returns ``-1.0`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. c:function:: void* PyLong_AsVoidPtr(PyObject *pylong) Convert a Python integer *pylong* to a C :c:expr:`void` pointer. If *pylong* cannot be converted, an :exc:`OverflowError` will be raised. This is only assured to produce a usable :c:expr:`void` pointer for values created with :c:func:`PyLong_FromVoidPtr`. Returns ``NULL`` on error. Use :c:func:`PyErr_Occurred` to disambiguate. .. c:function:: int PyUnstable_Long_IsCompact(const PyLongObject* op) Return 1 if *op* is compact, 0 otherwise. This function makes it possible for performance-critical code to implement a “fast path” for small integers. For compact values use :c:func:`PyUnstable_Long_CompactValue`; for others fall back to a :c:func:`PyLong_As* ` function or :c:func:`calling ` :meth:`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. .. c:function:: Py_ssize_t PyUnstable_Long_CompactValue(const PyLongObject* op) If *op* is compact, as determined by :c:func:`PyUnstable_Long_IsCompact`, return its value. Otherwise, the return value is undefined.