Slice Objects

.. c:var:: PyTypeObject PySlice_Type

 The type object for slice objects. This is the same as :class:`slice` in the
 Python layer.

.. c:function:: int PySlice_Check(PyObject *ob)

 Return true if *ob* is a slice object; *ob* must not be ``NULL``.

.. c:function:: PyObject* PySlice_New(PyObject *start, PyObject *stop, PyObject *step)

 Return a new slice object with the given values. The *start*, *stop*, and
 *step* parameters are used as the values of the slice object attributes of
 the same names. Any of the values may be ``NULL``, in which case the
 ``None`` will be used for the corresponding attribute. Return ``NULL`` if
 the new object could not be allocated.

.. c:function:: int PySlice_GetIndices(PyObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)

 Retrieve the start, stop and step indices from the slice object *slice*,
 assuming a sequence of length *length*. Treats indices greater than
 *length* as errors.

 Returns ``0`` on success and ``-1`` on error with no exception set (unless one of
 the indices was not :const:`None` and failed to be converted to an integer,
 in which case ``-1`` is returned with an exception set).

 You probably do not want to use this function.

 .. versionchanged:: 3.2
 The parameter type for the *slice* parameter was ``PySliceObject*``
 before.

.. c:function:: int PySlice_GetIndicesEx(PyObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, Py_ssize_t *slicelength)

 Usable replacement for :c:func:`PySlice_GetIndices`. Retrieve the start,
 stop, and step indices from the slice object *slice* assuming a sequence of
 length *length*, and store the length of the slice in *slicelength*. Out
 of bounds indices are clipped in a manner consistent with the handling of
 normal slices.

 Returns ``0`` on success and ``-1`` on error with exception set.

 .. note::
 This function is considered not safe for resizable sequences.
 Its invocation should be replaced by a combination of
 :c:func:`PySlice_Unpack` and :c:func:`PySlice_AdjustIndices` where ::

 if (PySlice_GetIndicesEx(slice, length, &start, &stop, &step, &slicelength) < 0) {
 // return error
 }

 is replaced by ::

 if (PySlice_Unpack(slice, &start, &stop, &step) < 0) {
 // return error
 }
 slicelength = PySlice_AdjustIndices(length, &start, &stop, step);

 .. versionchanged:: 3.2
 The parameter type for the *slice* parameter was ``PySliceObject*``
 before.

 .. versionchanged:: 3.6.1
 If ``Py_LIMITED_API`` is not set or set to the value between ``0x03050400``
 and ``0x03060000`` (not including) or ``0x03060100`` or higher
 :c:func:`!PySlice_GetIndicesEx` is implemented as a macro using
 :c:func:`!PySlice_Unpack` and :c:func:`!PySlice_AdjustIndices`.
 Arguments *start*, *stop* and *step* are evaluated more than once.

 .. deprecated:: 3.6.1
 If ``Py_LIMITED_API`` is set to the value less than ``0x03050400`` or
 between ``0x03060000`` and ``0x03060100`` (not including)
 :c:func:`!PySlice_GetIndicesEx` is a deprecated function.

.. c:function:: int PySlice_Unpack(PyObject *slice, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step)

 Extract the start, stop and step data members from a slice object as
 C integers. Silently reduce values larger than ``PY_SSIZE_T_MAX`` to
 ``PY_SSIZE_T_MAX``, silently boost the start and stop values less than
 ``PY_SSIZE_T_MIN`` to ``PY_SSIZE_T_MIN``, and silently boost the step
 values less than ``-PY_SSIZE_T_MAX`` to ``-PY_SSIZE_T_MAX``.

 Return ``-1`` on error, ``0`` on success.

 .. versionadded:: 3.6.1

.. c:function:: Py_ssize_t PySlice_AdjustIndices(Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t step)

 Adjust start/end slice indices assuming a sequence of the specified length.
 Out of bounds indices are clipped in a manner consistent with the handling
 of normal slices.

 Return the length of the slice. Always successful. Doesn't call Python
 code.

 .. versionadded:: 3.6.1

Ellipsis Object

.. c:var:: PyObject *Py_Ellipsis

 The Python ``Ellipsis`` object. This object has no methods. It needs to be
 treated just like any other object with respect to reference counts. Like
 :c:data:`Py_None` it is a singleton object.

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