cpython/Doc/c-api/float.rst

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.. highlightlang:: c
.. _floatobjects:
Floating Point Objects
----------------------
.. index:: object: floating point
.. 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
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This instance of :c:type:`PyTypeObject` represents the Python floating point
type. This is the same object as :class:`float` in the Python layer.
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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`.
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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`.
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.. c:function:: PyObject* PyFloat_FromString(PyObject *str)
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Create a :c:type:`PyFloatObject` object based on the string value in *str*, or
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*NULL* on failure.
.. 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
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*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
: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
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without error checking.
.. c:function:: PyObject* PyFloat_GetInfo(void)
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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()
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Return the maximum representable finite float *DBL_MAX* as C :c:type:`double`.
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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`.
Merged revisions 60481,60485,60489-60492,60494-60496,60498-60499,60501-60503,60505-60506,60508-60509,60523-60524,60532,60543,60545,60547-60548,60552-60567 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60553 | neal.norwitz | 2008-02-03 17:53:09 +0100 (Sun, 03 Feb 2008) | 1 line Ignore leaky warnings from test_asynchat ........ r60555 | christian.heimes | 2008-02-03 20:51:13 +0100 (Sun, 03 Feb 2008) | 1 line Another int -> pid_t case ........ r60560 | amaury.forgeotdarc | 2008-02-03 23:51:43 +0100 (Sun, 03 Feb 2008) | 6 lines Ensure that PySet_Add() operates on a newly created frozenset, like PyTuple_SetItem does. Add PyFrozenSet_Check(), which was not needed before; The list of Py*Set_Check* macros seems to be complete now. Add missing NEWS entries about all this. ........ r60563 | amaury.forgeotdarc | 2008-02-04 00:14:32 +0100 (Mon, 04 Feb 2008) | 2 lines Nasty typo in setobject.h ........ r60564 | amaury.forgeotdarc | 2008-02-04 00:15:32 +0100 (Mon, 04 Feb 2008) | 3 lines Correct test_mailbox on win32: since the test sets a custom 'colon' attribute to the main mailbox, copy it to secondary mailbox instances. ........ r60565 | amaury.forgeotdarc | 2008-02-04 00:57:24 +0100 (Mon, 04 Feb 2008) | 2 lines Let test_socketserver pass on win32, which does not have AF_UNIX sockets. ........ r60566 | jeffrey.yasskin | 2008-02-04 02:04:35 +0100 (Mon, 04 Feb 2008) | 2 lines Make int() and long() fall back to __trunc__(). See issue 2002. ........ r60567 | christian.heimes | 2008-02-04 19:00:12 +0100 (Mon, 04 Feb 2008) | 3 lines Patch #1953 I implemented the function sys._compact_freelists() and C API functions PyInt_/PyFloat_CompactFreeList() to compact the pre-allocated blocks of ints and floats. They allow the user to reduce the memory usage of a Python process that deals with lots of numbers. The patch also renames sys._cleartypecache to sys._clear_type_cache ........
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.. c:function:: int PyFloat_ClearFreeList()
Merged revisions 60481,60485,60489-60492,60494-60496,60498-60499,60501-60503,60505-60506,60508-60509,60523-60524,60532,60543,60545,60547-60548,60552-60567 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r60553 | neal.norwitz | 2008-02-03 17:53:09 +0100 (Sun, 03 Feb 2008) | 1 line Ignore leaky warnings from test_asynchat ........ r60555 | christian.heimes | 2008-02-03 20:51:13 +0100 (Sun, 03 Feb 2008) | 1 line Another int -> pid_t case ........ r60560 | amaury.forgeotdarc | 2008-02-03 23:51:43 +0100 (Sun, 03 Feb 2008) | 6 lines Ensure that PySet_Add() operates on a newly created frozenset, like PyTuple_SetItem does. Add PyFrozenSet_Check(), which was not needed before; The list of Py*Set_Check* macros seems to be complete now. Add missing NEWS entries about all this. ........ r60563 | amaury.forgeotdarc | 2008-02-04 00:14:32 +0100 (Mon, 04 Feb 2008) | 2 lines Nasty typo in setobject.h ........ r60564 | amaury.forgeotdarc | 2008-02-04 00:15:32 +0100 (Mon, 04 Feb 2008) | 3 lines Correct test_mailbox on win32: since the test sets a custom 'colon' attribute to the main mailbox, copy it to secondary mailbox instances. ........ r60565 | amaury.forgeotdarc | 2008-02-04 00:57:24 +0100 (Mon, 04 Feb 2008) | 2 lines Let test_socketserver pass on win32, which does not have AF_UNIX sockets. ........ r60566 | jeffrey.yasskin | 2008-02-04 02:04:35 +0100 (Mon, 04 Feb 2008) | 2 lines Make int() and long() fall back to __trunc__(). See issue 2002. ........ r60567 | christian.heimes | 2008-02-04 19:00:12 +0100 (Mon, 04 Feb 2008) | 3 lines Patch #1953 I implemented the function sys._compact_freelists() and C API functions PyInt_/PyFloat_CompactFreeList() to compact the pre-allocated blocks of ints and floats. They allow the user to reduce the memory usage of a Python process that deals with lots of numbers. The patch also renames sys._cleartypecache to sys._clear_type_cache ........
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Merged revisions 64722,64729,64753,64845-64846,64849,64871,64880-64882,64885,64888,64897,64900-64901,64915,64926-64929,64938-64941,64944,64961,64966,64973 via svnmerge from svn+ssh://pythondev@svn.python.org/python/trunk ........ r64722 | georg.brandl | 2008-07-05 12:13:36 +0200 (Sat, 05 Jul 2008) | 4 lines #2663: support an *ignore* argument to shutil.copytree(). Patch by Tarek Ziade. This is a new feature, but Barry authorized adding it in the beta period. ........ r64729 | mark.dickinson | 2008-07-05 13:33:52 +0200 (Sat, 05 Jul 2008) | 5 lines Issue 3188: accept float('infinity') as well as float('inf'). This makes the float constructor behave in the same way as specified by various other language standards, including C99, IEEE 754r, and the IBM Decimal standard. ........ r64753 | gregory.p.smith | 2008-07-06 05:35:58 +0200 (Sun, 06 Jul 2008) | 4 lines - Issue #2862: Make int and float freelist management consistent with other freelists. Changes their CompactFreeList apis into ClearFreeList apis and calls them via gc.collect(). ........ r64845 | raymond.hettinger | 2008-07-10 16:03:19 +0200 (Thu, 10 Jul 2008) | 1 line Issue 3301: Bisect functions behaved badly when lo was negative. ........ r64846 | raymond.hettinger | 2008-07-10 16:34:57 +0200 (Thu, 10 Jul 2008) | 1 line Issue 3285: Fractions from_float() and from_decimal() accept Integral arguments. ........ r64849 | andrew.kuchling | 2008-07-10 16:43:31 +0200 (Thu, 10 Jul 2008) | 1 line Wording changes ........ r64871 | raymond.hettinger | 2008-07-11 14:00:21 +0200 (Fri, 11 Jul 2008) | 1 line Add cautionary note on the use of PySequence_Fast_ITEMS. ........ r64880 | amaury.forgeotdarc | 2008-07-11 23:28:25 +0200 (Fri, 11 Jul 2008) | 5 lines #3317 in zipfile module, restore the previous names of global variables: some applications relied on them. Also remove duplicated lines. ........ r64881 | amaury.forgeotdarc | 2008-07-11 23:45:06 +0200 (Fri, 11 Jul 2008) | 3 lines #3342: In tracebacks, printed source lines were not indented since r62555. #3343: Py_DisplaySourceLine should be a private function. Rename it to _Py_DisplaySourceLine. ........ r64882 | josiah.carlson | 2008-07-12 00:17:14 +0200 (Sat, 12 Jul 2008) | 2 lines Fix for the AttributeError in test_asynchat. ........ r64885 | josiah.carlson | 2008-07-12 01:26:59 +0200 (Sat, 12 Jul 2008) | 2 lines Fixed test for asyncore. ........ r64888 | matthias.klose | 2008-07-12 09:51:48 +0200 (Sat, 12 Jul 2008) | 2 lines - Fix bashisms in Tools/faqwiz/move-faqwiz.sh ........ r64897 | benjamin.peterson | 2008-07-12 22:16:19 +0200 (Sat, 12 Jul 2008) | 1 line fix various doc typos #3320 ........ r64900 | alexandre.vassalotti | 2008-07-13 00:06:53 +0200 (Sun, 13 Jul 2008) | 2 lines Fixed typo. ........ r64901 | benjamin.peterson | 2008-07-13 01:41:19 +0200 (Sun, 13 Jul 2008) | 1 line #1778443 robotparser fixes from Aristotelis Mikropoulos ........ r64915 | nick.coghlan | 2008-07-13 16:52:36 +0200 (Sun, 13 Jul 2008) | 1 line Fix issue 3221 by emitting a RuntimeWarning instead of raising SystemError when the parent module can't be found during an absolute import (likely due to non-PEP 361 aware code which sets a module level __package__ attribute) ........ r64926 | martin.v.loewis | 2008-07-13 22:31:49 +0200 (Sun, 13 Jul 2008) | 2 lines Add turtle into the module index. ........ r64927 | alexandre.vassalotti | 2008-07-13 22:42:44 +0200 (Sun, 13 Jul 2008) | 3 lines Issue #3274: Use a less common identifier for the temporary variable in Py_CLEAR(). ........ r64928 | andrew.kuchling | 2008-07-13 23:43:25 +0200 (Sun, 13 Jul 2008) | 1 line Re-word ........ r64929 | andrew.kuchling | 2008-07-13 23:43:52 +0200 (Sun, 13 Jul 2008) | 1 line Add various items; move ctypes items into a subsection of their own ........ r64938 | andrew.kuchling | 2008-07-14 02:35:32 +0200 (Mon, 14 Jul 2008) | 1 line Typo fixes ........ r64939 | andrew.kuchling | 2008-07-14 02:40:55 +0200 (Mon, 14 Jul 2008) | 1 line Typo fix ........ r64940 | andrew.kuchling | 2008-07-14 03:18:16 +0200 (Mon, 14 Jul 2008) | 1 line Typo fix ........ r64941 | andrew.kuchling | 2008-07-14 03:18:31 +0200 (Mon, 14 Jul 2008) | 1 line Expand the multiprocessing section ........ r64944 | gregory.p.smith | 2008-07-14 08:06:48 +0200 (Mon, 14 Jul 2008) | 7 lines Fix posix.fork1() / os.fork1() to only call PyOS_AfterFork() in the child process rather than both parent and child. Does anyone actually use fork1()? It appears to be a Solaris thing but if Python is built with pthreads on Solaris, fork1() and fork() should be the same. ........ r64961 | jesse.noller | 2008-07-15 15:47:33 +0200 (Tue, 15 Jul 2008) | 1 line multiprocessing/connection.py patch to remove fqdn oddness for issue 3270 ........ r64966 | nick.coghlan | 2008-07-15 17:40:22 +0200 (Tue, 15 Jul 2008) | 1 line Add missing NEWS entry for r64962 ........ r64973 | jesse.noller | 2008-07-15 20:29:18 +0200 (Tue, 15 Jul 2008) | 1 line Revert 3270 patch: self._address is in pretty widespread use, need to revisit ........
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Clear the float free list. Return the number of items that could not
be freed.