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			We don't need direct C APIs to get at a bigint representation of PyLong but we do want the few people who need to understand how. Additional Author: CAM-Gerlach
		
			
				
	
	
		
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			324 lines
		
	
	
	
		
			11 KiB
		
	
	
	
		
			ReStructuredText
		
	
	
	
	
	
| .. highlight:: c
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| 
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| .. _longobjects:
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| 
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| Integer Objects
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| ---------------
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| 
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| .. index:: object: long integer
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|            object: integer
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| 
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| All integers are implemented as "long" integer objects of arbitrary size.
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| 
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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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| 
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| .. c:type:: PyLongObject
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| 
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|    This subtype of :c:type:`PyObject` represents a Python integer object.
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| 
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| 
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| .. c:var:: PyTypeObject PyLong_Type
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| 
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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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| 
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| 
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| .. c:function:: int PyLong_Check(PyObject *p)
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| 
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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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| 
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| 
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| .. c:function:: int PyLong_CheckExact(PyObject *p)
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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromLong(long v)
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| 
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|    Return a new :c:type:`PyLongObject` object from *v*, or ``NULL`` on failure.
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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromUnsignedLong(unsigned long v)
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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromSsize_t(Py_ssize_t v)
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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromSize_t(size_t v)
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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromLongLong(long long v)
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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromUnsignedLongLong(unsigned long long v)
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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromDouble(double v)
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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromString(const char *str, char **pend, int base)
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| 
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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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| 
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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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| 
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| 
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| .. c:function:: PyObject* PyLong_FromUnicodeObject(PyObject *u, int base)
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| 
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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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| 
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|    .. versionadded:: 3.3
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| 
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| 
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| .. c:function:: PyObject* PyLong_FromVoidPtr(void *p)
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| 
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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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| 
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| 
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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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| 
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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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| 
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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:`__index__` method
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|    (if present) to convert it to a :c:type:`PyLongObject`.
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| 
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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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| 
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|    Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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| 
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|    .. versionchanged:: 3.8
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|       Use :meth:`__index__` if available.
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| 
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|    .. versionchanged:: 3.10
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|       This function will no longer use :meth:`__int__`.
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| 
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| 
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| .. c:function:: long PyLong_AsLongAndOverflow(PyObject *obj, int *overflow)
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| 
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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:`__index__`
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|    method (if present) to convert it to a :c:type:`PyLongObject`.
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| 
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|    If the value of *obj* is greater than :const:`LONG_MAX` or less than
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|    :const:`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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| 
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|    Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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| 
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|    .. versionchanged:: 3.8
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|       Use :meth:`__index__` if available.
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| 
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|    .. versionchanged:: 3.10
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|       This function will no longer use :meth:`__int__`.
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| 
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| 
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| .. c:function:: long long PyLong_AsLongLong(PyObject *obj)
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| 
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|    .. index::
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|       single: OverflowError (built-in exception)
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| 
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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:`__index__` method
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|    (if present) to convert it to a :c:type:`PyLongObject`.
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| 
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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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| 
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|    Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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| 
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|    .. versionchanged:: 3.8
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|       Use :meth:`__index__` if available.
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| 
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|    .. versionchanged:: 3.10
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|       This function will no longer use :meth:`__int__`.
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| 
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| 
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| .. c:function:: long long PyLong_AsLongLongAndOverflow(PyObject *obj, int *overflow)
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| 
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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:`__index__` method
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|    (if present) to convert it to a :c:type:`PyLongObject`.
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| 
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|    If the value of *obj* is greater than :const:`LLONG_MAX` or less than
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|    :const:`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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| 
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|    Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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| 
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|    .. versionadded:: 3.2
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| 
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|    .. versionchanged:: 3.8
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|       Use :meth:`__index__` if available.
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| 
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|    .. versionchanged:: 3.10
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|       This function will no longer use :meth:`__int__`.
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| 
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| 
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| .. c:function:: Py_ssize_t PyLong_AsSsize_t(PyObject *pylong)
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| 
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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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| 
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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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| 
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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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| 
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|    Returns ``-1`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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| 
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| 
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| .. c:function:: unsigned long PyLong_AsUnsignedLong(PyObject *pylong)
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| 
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| .. c:function:: size_t PyLong_AsSize_t(PyObject *pylong)
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| 
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| .. c:function:: unsigned long long PyLong_AsUnsignedLongLong(PyObject *pylong)
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| 
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|    .. index::
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|       single: OverflowError (built-in exception)
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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| 
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| .. c:function:: unsigned long PyLong_AsUnsignedLongMask(PyObject *obj)
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| 
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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:`__index__`
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|    method (if present) to convert it to a :c:type:`PyLongObject`.
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| 
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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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| 
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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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| 
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|    .. versionchanged:: 3.8
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|       Use :meth:`__index__` if available.
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| 
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|    .. versionchanged:: 3.10
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|       This function will no longer use :meth:`__int__`.
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| 
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| 
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| .. c:function:: unsigned long long PyLong_AsUnsignedLongLongMask(PyObject *obj)
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| 
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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:`__index__` method (if present) to convert it to a
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|    :c:type:`PyLongObject`.
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| 
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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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| 
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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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| 
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|    .. versionchanged:: 3.8
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|       Use :meth:`__index__` if available.
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| 
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|    .. versionchanged:: 3.10
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|       This function will no longer use :meth:`__int__`.
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| 
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| 
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| .. c:function:: double PyLong_AsDouble(PyObject *pylong)
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| 
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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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| 
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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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| 
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|    Returns ``-1.0`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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| 
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| 
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| .. c:function:: void* PyLong_AsVoidPtr(PyObject *pylong)
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| 
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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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| 
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|    Returns ``NULL`` on error.  Use :c:func:`PyErr_Occurred` to disambiguate.
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