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	* Rename _PyLong_AsInt() to PyLong_AsInt(). * Add documentation. * Add test. * For now, keep _PyLong_AsInt() as an alias to PyLong_AsInt().
		
			
				
	
	
		
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			356 lines
		
	
	
	
		
			12 KiB
		
	
	
	
		
			ReStructuredText
		
	
	
	
	
	
.. highlight:: c
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.. _longobjects:
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Integer Objects
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---------------
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.. index:: pair: object; long integer
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           pair: object; integer
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All integers are implemented as "long" integer objects of arbitrary size.
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On error, most ``PyLong_As*`` APIs return ``(return type)-1`` which cannot be
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distinguished from a number.  Use :c:func:`PyErr_Occurred` to disambiguate.
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.. c:type:: PyLongObject
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   This subtype of :c:type:`PyObject` represents a Python integer object.
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.. c:var:: PyTypeObject PyLong_Type
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   This instance of :c:type:`PyTypeObject` represents the Python integer type.
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   This is the same object as :class:`int` in the Python layer.
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.. c:function:: int PyLong_Check(PyObject *p)
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   Return true if its argument is a :c:type:`PyLongObject` or a subtype of
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   :c:type:`PyLongObject`.  This function always succeeds.
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.. c:function:: int PyLong_CheckExact(PyObject *p)
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   Return true if its argument is a :c:type:`PyLongObject`, but not a subtype of
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   :c:type:`PyLongObject`.  This function always succeeds.
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.. c:function:: PyObject* PyLong_FromLong(long v)
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   Return a new :c:type:`PyLongObject` object from *v*, or ``NULL`` on failure.
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   The current implementation keeps an array of integer objects for all integers
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   between ``-5`` and ``256``. When you create an int in that range you actually
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   just get back a reference to the existing object.
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.. c:function:: PyObject* PyLong_FromUnsignedLong(unsigned long v)
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   Return a new :c:type:`PyLongObject` object from a C :c:expr:`unsigned long`, or
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   ``NULL`` on failure.
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.. c:function:: PyObject* PyLong_FromSsize_t(Py_ssize_t v)
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   Return a new :c:type:`PyLongObject` object from a C :c:type:`Py_ssize_t`, or
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   ``NULL`` on failure.
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.. c:function:: PyObject* PyLong_FromSize_t(size_t v)
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   Return a new :c:type:`PyLongObject` object from a C :c:type:`size_t`, or
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   ``NULL`` on failure.
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.. c:function:: PyObject* PyLong_FromLongLong(long long v)
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   Return a new :c:type:`PyLongObject` object from a C :c:expr:`long long`, or ``NULL``
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   on failure.
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.. c:function:: PyObject* PyLong_FromUnsignedLongLong(unsigned long long v)
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   Return a new :c:type:`PyLongObject` object from a C :c:expr:`unsigned long long`,
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   or ``NULL`` on failure.
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.. c:function:: PyObject* PyLong_FromDouble(double v)
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   Return a new :c:type:`PyLongObject` object from the integer part of *v*, or
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   ``NULL`` on failure.
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.. c:function:: PyObject* PyLong_FromString(const char *str, char **pend, int base)
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   Return a new :c:type:`PyLongObject` based on the string value in *str*, which
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   is interpreted according to the radix in *base*, or ``NULL`` on failure.  If
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   *pend* is non-``NULL``, *\*pend* will point to the end of *str* on success or
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   to the first character that could not be processed on error.  If *base* is ``0``,
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   *str* is interpreted using the :ref:`integers` definition; in this case, leading
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   zeros in a non-zero decimal number raises a :exc:`ValueError`.  If *base* is not
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   ``0``, it must be between ``2`` and ``36``, inclusive.  Leading and trailing
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   whitespace and single underscores after a base specifier and between digits are
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   ignored.  If there are no digits or *str* is not NULL-terminated following the
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   digits and trailing whitespace, :exc:`ValueError` will be raised.
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   .. seealso:: Python methods :meth:`int.to_bytes` and :meth:`int.from_bytes`
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      to convert a :c:type:`PyLongObject` to/from an array of bytes in base
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      ``256``. You can call those from C using :c:func:`PyObject_CallMethod`.
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.. c:function:: PyObject* PyLong_FromUnicodeObject(PyObject *u, int base)
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   Convert a sequence of Unicode digits in the string *u* to a Python integer
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   value.
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   .. versionadded:: 3.3
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.. c:function:: PyObject* PyLong_FromVoidPtr(void *p)
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   Create a Python integer from the pointer *p*. The pointer value can be
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   retrieved from the resulting value using :c:func:`PyLong_AsVoidPtr`.
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.. XXX alias PyLong_AS_LONG (for now)
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.. c:function:: long PyLong_AsLong(PyObject *obj)
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   .. index::
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      single: LONG_MAX
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      single: OverflowError (built-in exception)
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   Return a C :c:expr:`long` representation of *obj*.  If *obj* is not an
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   instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method
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   (if present) to convert it to a :c:type:`PyLongObject`.
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   Raise :exc:`OverflowError` if the value of *obj* is out of range for a
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   :c:expr:`long`.
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   Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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   .. versionchanged:: 3.8
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      Use :meth:`~object.__index__` if available.
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   .. versionchanged:: 3.10
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      This function will no longer use :meth:`~object.__int__`.
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.. c:function:: int PyLong_AsInt(PyObject *obj)
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   Similar to :c:func:`PyLong_AsLong`, but store the result in a C
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   :c:expr:`int` instead of a C :c:expr:`long`.
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   .. versionadded:: 3.13
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.. c:function:: long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow)
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   Return a C :c:expr:`long` representation of *obj*.  If *obj* is not an
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   instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__`
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   method (if present) to convert it to a :c:type:`PyLongObject`.
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   If the value of *obj* is greater than :c:macro:`LONG_MAX` or less than
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   :c:macro:`LONG_MIN`, set *\*overflow* to ``1`` or ``-1``, respectively, and
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   return ``-1``; otherwise, set *\*overflow* to ``0``.  If any other exception
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   occurs set *\*overflow* to ``0`` and return ``-1`` as usual.
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   Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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   .. versionchanged:: 3.8
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      Use :meth:`~object.__index__` if available.
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   .. versionchanged:: 3.10
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      This function will no longer use :meth:`~object.__int__`.
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.. c:function:: long long PyLong_AsLongLong(PyObject *obj)
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   .. index::
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      single: OverflowError (built-in exception)
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   Return a C :c:expr:`long long` representation of *obj*.  If *obj* is not an
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   instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method
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   (if present) to convert it to a :c:type:`PyLongObject`.
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   Raise :exc:`OverflowError` if the value of *obj* is out of range for a
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   :c:expr:`long long`.
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   Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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   .. versionchanged:: 3.8
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      Use :meth:`~object.__index__` if available.
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   .. versionchanged:: 3.10
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      This function will no longer use :meth:`~object.__int__`.
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.. c:function:: long long PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow)
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   Return a C :c:expr:`long long` representation of *obj*.  If *obj* is not an
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   instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__` method
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   (if present) to convert it to a :c:type:`PyLongObject`.
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   If the value of *obj* is greater than :c:macro:`LLONG_MAX` or less than
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   :c:macro:`LLONG_MIN`, set *\*overflow* to ``1`` or ``-1``, respectively,
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   and return ``-1``; otherwise, set *\*overflow* to ``0``.  If any other
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   exception occurs set *\*overflow* to ``0`` and return ``-1`` as usual.
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   Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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   .. versionadded:: 3.2
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   .. versionchanged:: 3.8
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      Use :meth:`~object.__index__` if available.
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   .. versionchanged:: 3.10
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      This function will no longer use :meth:`~object.__int__`.
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.. c:function:: Py_ssize_t PyLong_AsSsize_t(PyObject *pylong)
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   .. index::
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      single: PY_SSIZE_T_MAX
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      single: OverflowError (built-in exception)
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   Return a C :c:type:`Py_ssize_t` representation of *pylong*.  *pylong* must
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   be an instance of :c:type:`PyLongObject`.
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   Raise :exc:`OverflowError` if the value of *pylong* is out of range for a
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   :c:type:`Py_ssize_t`.
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   Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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.. c:function:: unsigned long PyLong_AsUnsignedLong(PyObject *pylong)
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   .. index::
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      single: ULONG_MAX
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      single: OverflowError (built-in exception)
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   Return a C :c:expr:`unsigned long` representation of *pylong*.  *pylong*
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   must be an instance of :c:type:`PyLongObject`.
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   Raise :exc:`OverflowError` if the value of *pylong* is out of range for a
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   :c:expr:`unsigned long`.
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   Returns ``(unsigned long)-1`` on error.
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   Use :c:func:`PyErr_Occurred` to disambiguate.
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.. c:function:: size_t PyLong_AsSize_t(PyObject *pylong)
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   .. index::
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      single: SIZE_MAX
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      single: OverflowError (built-in exception)
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   Return a C :c:type:`size_t` representation of *pylong*.  *pylong* must be
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   an instance of :c:type:`PyLongObject`.
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   Raise :exc:`OverflowError` if the value of *pylong* is out of range for a
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   :c:type:`size_t`.
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   Returns ``(size_t)-1`` on error.
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   Use :c:func:`PyErr_Occurred` to disambiguate.
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.. c:function:: unsigned long long PyLong_AsUnsignedLongLong(PyObject *pylong)
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   .. index::
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      single: OverflowError (built-in exception)
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   Return a C :c:expr:`unsigned long long` representation of *pylong*.  *pylong*
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   must be an instance of :c:type:`PyLongObject`.
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   Raise :exc:`OverflowError` if the value of *pylong* is out of range for an
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   :c:expr:`unsigned long long`.
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   Returns ``(unsigned long long)-1`` on error.
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   Use :c:func:`PyErr_Occurred` to disambiguate.
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   .. versionchanged:: 3.1
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      A negative *pylong* now raises :exc:`OverflowError`, not :exc:`TypeError`.
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.. c:function:: unsigned long PyLong_AsUnsignedLongMask(PyObject *obj)
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   Return a C :c:expr:`unsigned long` representation of *obj*.  If *obj* is not
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   an instance of :c:type:`PyLongObject`, first call its :meth:`~object.__index__`
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   method (if present) to convert it to a :c:type:`PyLongObject`.
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   If the value of *obj* is out of range for an :c:expr:`unsigned long`,
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   return the reduction of that value modulo ``ULONG_MAX + 1``.
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   Returns ``(unsigned long)-1`` on error.  Use :c:func:`PyErr_Occurred` to
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   disambiguate.
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   .. versionchanged:: 3.8
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      Use :meth:`~object.__index__` if available.
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   .. versionchanged:: 3.10
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      This function will no longer use :meth:`~object.__int__`.
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.. c:function:: unsigned long long PyLong_AsUnsignedLongLongMask(PyObject *obj)
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   Return a C :c:expr:`unsigned long long` representation of *obj*.  If *obj*
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   is not an instance of :c:type:`PyLongObject`, first call its
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   :meth:`~object.__index__` method (if present) to convert it to a
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   :c:type:`PyLongObject`.
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   If the value of *obj* is out of range for an :c:expr:`unsigned long long`,
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   return the reduction of that value modulo ``ULLONG_MAX + 1``.
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   Returns ``(unsigned long long)-1`` on error.  Use :c:func:`PyErr_Occurred`
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   to disambiguate.
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   .. versionchanged:: 3.8
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      Use :meth:`~object.__index__` if available.
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   .. versionchanged:: 3.10
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      This function will no longer use :meth:`~object.__int__`.
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.. c:function:: double PyLong_AsDouble(PyObject *pylong)
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   Return a C :c:expr:`double` representation of *pylong*.  *pylong* must be
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   an instance of :c:type:`PyLongObject`.
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   Raise :exc:`OverflowError` if the value of *pylong* is out of range for a
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   :c:expr:`double`.
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   Returns ``-1.0`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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.. c:function:: void* PyLong_AsVoidPtr(PyObject *pylong)
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   Convert a Python integer *pylong* to a C :c:expr:`void` pointer.
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   If *pylong* cannot be converted, an :exc:`OverflowError` will be raised.  This
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   is only assured to produce a usable :c:expr:`void` pointer for values created
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   with :c:func:`PyLong_FromVoidPtr`.
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   Returns ``NULL`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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.. c:function:: int PyUnstable_Long_IsCompact(const PyLongObject* op)
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   Return 1 if *op* is compact, 0 otherwise.
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   This function makes it possible for performance-critical code to implement
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   a “fast path” for small integers. For compact values use
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   :c:func:`PyUnstable_Long_CompactValue`; for others fall back to a
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   :c:func:`PyLong_As* <PyLong_AsSize_t>` function or
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   :c:func:`calling <PyObject_CallMethod>` :meth:`int.to_bytes`.
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   The speedup is expected to be negligible for most users.
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   Exactly what values are considered compact is an implementation detail
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   and is subject to change.
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.. c:function:: Py_ssize_t PyUnstable_Long_CompactValue(const PyLongObject* op)
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   If *op* is compact, as determined by :c:func:`PyUnstable_Long_IsCompact`,
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   return its value.
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   Otherwise, the return value is undefined.
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