cpython/Doc/c-api/float.rst

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.. highlightlang:: c
.. _floatobjects:
Floating Point Objects
----------------------
.. index:: object: floating point
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.. c:type:: PyFloatObject
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This subtype of :c:type:`PyObject` represents a Python floating point object.
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.. c:var:: PyTypeObject PyFloat_Type
.. index:: single: FloatType (in modules types)
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This instance of :c:type:`PyTypeObject` represents the Python floating point
type. This is the same object as ``float`` and ``types.FloatType``.
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.. c:function:: int PyFloat_Check(PyObject *p)
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Return true if its argument is a :c:type:`PyFloatObject` or a subtype of
:c:type:`PyFloatObject`.
.. versionchanged:: 2.2
Allowed subtypes to be accepted.
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.. c:function:: int PyFloat_CheckExact(PyObject *p)
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Return true if its argument is a :c:type:`PyFloatObject`, but not a subtype of
:c:type:`PyFloatObject`.
.. versionadded:: 2.2
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.. c:function:: PyObject* PyFloat_FromString(PyObject *str, char **pend)
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Create a :c:type:`PyFloatObject` object based on the string value in *str*, or
*NULL* on failure. The *pend* argument is ignored. It remains only for
backward compatibility.
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.. c:function:: PyObject* PyFloat_FromDouble(double v)
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Create a :c:type:`PyFloatObject` object from *v*, or *NULL* on failure.
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.. c:function:: double PyFloat_AsDouble(PyObject *pyfloat)
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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.
This method returns ``-1.0`` upon failure, so one should call
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:c:func:`PyErr_Occurred` to check for errors.
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.. c:function:: double PyFloat_AS_DOUBLE(PyObject *pyfloat)
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Return a C :c:type:`double` representation of the contents of *pyfloat*, but
without error checking.
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.. 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`.
.. versionadded:: 2.6
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.. c:function:: double PyFloat_GetMax()
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Return the maximum representable finite float *DBL_MAX* as C :c:type:`double`.
.. versionadded:: 2.6
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.. c:function:: double PyFloat_GetMin()
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Return the minimum normalized positive float *DBL_MIN* as C :c:type:`double`.
.. versionadded:: 2.6
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.. c:function:: int PyFloat_ClearFreeList()
Clear the float free list. Return the number of items that could not
be freed.
.. versionadded:: 2.6
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.. c:function:: void PyFloat_AsString(char *buf, PyFloatObject *v)
Convert the argument *v* to a string, using the same rules as
:func:`str`. The length of *buf* should be at least 100.
This function is unsafe to call because it writes to a buffer whose
length it does not know.
.. deprecated:: 2.7
Use :func:`PyObject_Str` or :func:`PyOS_double_to_string` instead.
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.. c:function:: void PyFloat_AsReprString(char *buf, PyFloatObject *v)
Same as PyFloat_AsString, except uses the same rules as
:func:`repr`. The length of *buf* should be at least 100.
This function is unsafe to call because it writes to a buffer whose
length it does not know.
.. deprecated:: 2.7
Use :func:`PyObject_Repr` or :func:`PyOS_double_to_string` instead.