cpython/Doc/c-api/float.rst
Antonio Cuni 315fc52db1
bpo-42528: Improve the docs of most Py*_Check{,Exact} API calls (GH-23602)
I think that none of these API calls can fail, but only few of them are
documented as such. Add the sentence "This function always succeeds" (which is
the same already used e.g. by PyNumber_Check) to all of them.
2021-01-06 12:38:26 +01:00

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ReStructuredText

.. highlight:: c
.. _floatobjects:
Floating Point Objects
----------------------
.. index:: object: floating point
.. c:type:: PyFloatObject
This subtype of :c:type:`PyObject` represents a Python floating point object.
.. c:var:: PyTypeObject PyFloat_Type
This instance of :c:type:`PyTypeObject` represents the Python floating point
type. This is the same object as :class:`float` in the Python layer.
.. c:function:: int PyFloat_Check(PyObject *p)
Return true if its argument is a :c:type:`PyFloatObject` or a subtype of
:c:type:`PyFloatObject`. This function always succeeds.
.. c:function:: int PyFloat_CheckExact(PyObject *p)
Return true if its argument is a :c:type:`PyFloatObject`, but not a subtype of
:c:type:`PyFloatObject`. This function always succeeds.
.. c:function:: PyObject* PyFloat_FromString(PyObject *str)
Create a :c:type:`PyFloatObject` object based on the string value in *str*, or
``NULL`` on failure.
.. c:function:: PyObject* PyFloat_FromDouble(double v)
Create a :c:type:`PyFloatObject` object from *v*, or ``NULL`` on failure.
.. c:function:: double PyFloat_AsDouble(PyObject *pyfloat)
Return a C :c:type:`double` representation of the contents of *pyfloat*. If
*pyfloat* is not a Python floating point object but has a :meth:`__float__`
method, this method will first be called to convert *pyfloat* into a float.
If ``__float__()`` is not defined then it falls back to :meth:`__index__`.
This method returns ``-1.0`` upon failure, so one should call
:c:func:`PyErr_Occurred` to check for errors.
.. versionchanged:: 3.8
Use :meth:`__index__` if available.
.. c:function:: double PyFloat_AS_DOUBLE(PyObject *pyfloat)
Return a C :c:type:`double` representation of the contents of *pyfloat*, but
without error checking.
.. c:function:: PyObject* PyFloat_GetInfo(void)
Return a structseq instance which contains information about the
precision, minimum and maximum values of a float. It's a thin wrapper
around the header file :file:`float.h`.
.. c:function:: double PyFloat_GetMax()
Return the maximum representable finite float *DBL_MAX* as C :c:type:`double`.
.. c:function:: double PyFloat_GetMin()
Return the minimum normalized positive float *DBL_MIN* as C :c:type:`double`.