What's New in Python 3.9: Reorganize C API Changes (GH-19794)
Move Build Changes and C API Changes to the end of the document. Most Python users don't build Python themselves and don't use the C API. Other changes: * Add Build Changes section * Add sub-sections to the C API Changes * Sort modules in Improved Modules section: move nntplib after multiprocessing
This commit is contained in:
Victor Stinner
GitHub
parent
57697245e1
commit
e5963ee320
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@ -369,13 +369,6 @@ Add :func:`math.ulp`: return the value of the least significant bit
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of a float.
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(Contributed by Victor Stinner in :issue:`39310`.)
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nntplib
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-------
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:class:`~nntplib.NNTP` and :class:`~nntplib.NNTP_SSL` now raise a :class:`ValueError`
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if the given timeout for their constructor is zero to prevent the creation of
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a non-blocking socket. (Contributed by Dong-hee Na in :issue:`39259`.)
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multiprocessing
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---------------
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@ -384,6 +377,13 @@ The :class:`multiprocessing.SimpleQueue` class has a new
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queue.
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(Contributed by Victor Stinner in :issue:`30966`.)
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nntplib
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-------
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:class:`~nntplib.NNTP` and :class:`~nntplib.NNTP_SSL` now raise a :class:`ValueError`
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if the given timeout for their constructor is zero to prevent the creation of
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a non-blocking socket. (Contributed by Dong-hee Na in :issue:`39259`.)
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os
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--
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@ -534,157 +534,6 @@ Optimizations
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Stinner in :issue:`38061`.)
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Build and C API Changes
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=======================
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* New :c:func:`PyFrame_GetCode` function: get a frame code.
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New :c:func:`PyFrame_GetBack` function: get the frame next outer frame.
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(Contributed by Victor Stinner in :issue:`40421`.)
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* Add :c:func:`PyFrame_GetLineNumber` to the limited C API.
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(Contributed by Victor Stinner in :issue:`40421`.)
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* New :c:func:`PyThreadState_GetInterpreter` and
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:c:func:`PyInterpreterState_Get` functions to get the interpreter.
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New :c:func:`PyThreadState_GetFrame` function to get the current frame of a
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Python thread state.
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New :c:func:`PyThreadState_GetID` function: get the unique identifier of a
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Python thread state.
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(Contributed by Victor Stinner in :issue:`39947`.)
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* Add ``--with-platlibdir`` option to the ``configure`` script: name of the
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platform-specific library directory, stored in the new :attr:`sys.platlibdir`
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attribute. See :attr:`sys.platlibdir` attribute for more information.
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(Contributed by Jan Matějek, Matěj Cepl, Charalampos Stratakis and Victor Stinner in :issue:`1294959`.)
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* Add a new public :c:func:`PyObject_CallNoArgs` function to the C API, which
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calls a callable Python object without any arguments. It is the most efficient
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way to call a callable Python object without any argument.
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(Contributed by Victor Stinner in :issue:`37194`.)
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* The global variable :c:data:`PyStructSequence_UnnamedField` is now a constant
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and refers to a constant string.
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(Contributed by Serhiy Storchaka in :issue:`38650`.)
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* Exclude ``PyFPE_START_PROTECT()`` and ``PyFPE_END_PROTECT()`` macros of
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``pyfpe.h`` from ``Py_LIMITED_API`` (stable API).
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(Contributed by Victor Stinner in :issue:`38835`.)
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* The ``tp_print`` slot of :ref:`PyTypeObject <type-structs>` has been removed.
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It was used for printing objects to files in Python 2.7 and before. Since
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Python 3.0, it has been ignored and unused.
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(Contributed by Jeroen Demeyer in :issue:`36974`.)
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* On non-Windows platforms, the :c:func:`setenv` and :c:func:`unsetenv`
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functions are now required to build Python.
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(Contributed by Victor Stinner in :issue:`39395`.)
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* The ``COUNT_ALLOCS`` special build macro has been removed.
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(Contributed by Victor Stinner in :issue:`39489`.)
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* Changes in the limited C API (if ``Py_LIMITED_API`` macro is defined):
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* Provide :c:func:`Py_EnterRecursiveCall` and :c:func:`Py_LeaveRecursiveCall`
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as regular functions for the limited API. Previously, there were defined as
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macros, but these macros didn't compile with the limited C API which cannot
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access ``PyThreadState.recursion_depth`` field (the structure is opaque in
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the limited C API).
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* Exclude the following functions from the limited C API:
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* ``_Py_CheckRecursionLimit``
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* ``_Py_NewReference()``
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* ``_Py_ForgetReference()``
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* ``_PyTraceMalloc_NewReference()``
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* ``_Py_GetRefTotal()``
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* The trashcan mechanism which never worked in the limited C API.
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* ``PyTrash_UNWIND_LEVEL``
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* ``Py_TRASHCAN_BEGIN_CONDITION``
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* ``Py_TRASHCAN_BEGIN``
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* ``Py_TRASHCAN_END``
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* ``Py_TRASHCAN_SAFE_BEGIN``
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* ``Py_TRASHCAN_SAFE_END``
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* The following static inline functions or macros become regular "opaque"
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function to hide implementation details:
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* ``_Py_NewReference()``
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* ``PyObject_INIT()`` and ``PyObject_INIT_VAR()`` become aliases to
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:c:func:`PyObject_Init` and :c:func:`PyObject_InitVar` in the limited C
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API, but are overriden with static inline function otherwise. Thanks to
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that, it was possible to exclude ``_Py_NewReference()`` from the limited
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C API.
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* Move following functions and definitions to the internal C API:
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* ``_PyDebug_PrintTotalRefs()``
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* ``_Py_PrintReferences()``
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* ``_Py_PrintReferenceAddresses()``
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* ``_Py_tracemalloc_config``
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* ``_Py_AddToAllObjects()`` (specific to ``Py_TRACE_REFS`` build)
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(Contributed by Victor Stinner in :issue:`38644` and :issue:`39542`.)
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* ``PyInterpreterState.eval_frame`` (:pep:`523`) now requires a new mandatory
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*tstate* parameter (``PyThreadState*``).
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(Contributed by Victor Stinner in :issue:`38500`.)
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* Extension modules: :c:member:`~PyModuleDef.m_traverse`,
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:c:member:`~PyModuleDef.m_clear` and :c:member:`~PyModuleDef.m_free`
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functions of :c:type:`PyModuleDef` are no longer called if the module state
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was requested but is not allocated yet. This is the case immediately after
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the module is created and before the module is executed
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(:c:data:`Py_mod_exec` function). More precisely, these functions are not called
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if :c:member:`~PyModuleDef.m_size` is greater than 0 and the module state (as
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returned by :c:func:`PyModule_GetState`) is ``NULL``.
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Extension modules without module state (``m_size <= 0``) are not affected.
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* If :c:func:`Py_AddPendingCall` is called in a subinterpreter, the function is
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now scheduled to be called from the subinterpreter, rather than being called
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from the main interpreter. Each subinterpreter now has its own list of
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scheduled calls.
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(Contributed by Victor Stinner in :issue:`39984`.)
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* Remove ``_PyRuntime.getframe`` hook and remove ``_PyThreadState_GetFrame``
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macro which was an alias to ``_PyRuntime.getframe``. They were only exposed
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by the internal C API. Remove also ``PyThreadFrameGetter`` type.
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(Contributed by Victor Stinner in :issue:`39946`.)
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* The :c:func:`PyModule_AddType` function is added to help adding a type to a module.
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(Contributed by Dong-hee Na in :issue:`40024`.)
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* The Windows registry is no longer used to initialize :data:`sys.path` when
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the ``-E`` option is used. This is significant when embedding Python on
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Windows.
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(Contributed by Zackery Spytz in :issue:`8901`.)
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* Add the functions :c:func:`PyObject_GC_IsTracked` and
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:c:func:`PyObject_GC_IsFinalized` to the public API to allow to query if
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Python objects are being currently tracked or have been already finalized by
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the garbage collector respectively. (Contributed by Pablo Galindo in
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:issue:`40241`.)
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* Remove the following functions from the C API. Call :c:func:`PyGC_Collect`
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explicitly to clear all free lists.
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(Contributed by Inada Naoki and Victor Stinner in :issue:`37340`,
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:issue:`38896` and :issue:`40428`.)
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* ``PyAsyncGen_ClearFreeLists()``
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* ``PyContext_ClearFreeList()``
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* ``PyDict_ClearFreeList()``
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* ``PyFloat_ClearFreeList()``
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* ``PyFrame_ClearFreeList()``
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* ``PyList_ClearFreeList()``
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* ``PyMethod_ClearFreeList()`` and ``PyCFunction_ClearFreeList()``:
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the free lists of bound method objects have been removed.
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* ``PySet_ClearFreeList()``: the set free list has been removed
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in Python 3.4.
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* ``PyTuple_ClearFreeList()``
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* ``PyUnicode_ClearFreeList()``: the Unicode free list has been removed in
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Python 3.3.
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Deprecated
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==========
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@ -729,7 +578,7 @@ Deprecated
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deprecated and will be removed in version 3.11.
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(Contributed by Yury Selivanov and Kyle Stanley in :issue:`34790`.)
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* binhex4 and hexbin4 standards are now deprecated. The :`binhex` module
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* binhex4 and hexbin4 standards are now deprecated. The :mod:`binhex` module
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and the following :mod:`binascii` functions are now deprecated:
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* :func:`~binascii.b2a_hqx`, :func:`~binascii.a2b_hqx`
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@ -934,3 +783,168 @@ CPython bytecode changes
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:keyword:`assert` statement. Previously, the assert statement would not work
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correctly if the :exc:`AssertionError` exception was being shadowed.
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(Contributed by Zackery Spytz in :issue:`34880`.)
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Build Changes
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=============
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* Add ``--with-platlibdir`` option to the ``configure`` script: name of the
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platform-specific library directory, stored in the new :attr:`sys.platlibdir`
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attribute. See :attr:`sys.platlibdir` attribute for more information.
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(Contributed by Jan Matějek, Matěj Cepl, Charalampos Stratakis
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and Victor Stinner in :issue:`1294959`.)
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* The ``COUNT_ALLOCS`` special build macro has been removed.
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(Contributed by Victor Stinner in :issue:`39489`.)
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* On non-Windows platforms, the :c:func:`setenv` and :c:func:`unsetenv`
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functions are now required to build Python.
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(Contributed by Victor Stinner in :issue:`39395`.)
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C API Changes
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=============
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New Features
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------------
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* Add :c:func:`PyFrame_GetCode` function: get a frame code.
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Add :c:func:`PyFrame_GetBack` function: get the frame next outer frame.
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(Contributed by Victor Stinner in :issue:`40421`.)
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* Add :c:func:`PyFrame_GetLineNumber` to the limited C API.
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(Contributed by Victor Stinner in :issue:`40421`.)
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* Add :c:func:`PyThreadState_GetInterpreter` and
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:c:func:`PyInterpreterState_Get` functions to get the interpreter.
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Add :c:func:`PyThreadState_GetFrame` function to get the current frame of a
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Python thread state.
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Add :c:func:`PyThreadState_GetID` function: get the unique identifier of a
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Python thread state.
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(Contributed by Victor Stinner in :issue:`39947`.)
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* Add a new public :c:func:`PyObject_CallNoArgs` function to the C API, which
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calls a callable Python object without any arguments. It is the most efficient
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way to call a callable Python object without any argument.
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(Contributed by Victor Stinner in :issue:`37194`.)
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* Changes in the limited C API (if ``Py_LIMITED_API`` macro is defined):
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* Provide :c:func:`Py_EnterRecursiveCall` and :c:func:`Py_LeaveRecursiveCall`
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as regular functions for the limited API. Previously, there were defined as
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macros, but these macros didn't compile with the limited C API which cannot
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access ``PyThreadState.recursion_depth`` field (the structure is opaque in
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the limited C API).
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* ``PyObject_INIT()`` and ``PyObject_INIT_VAR()`` become regular "opaque"
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function to hide implementation details.
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(Contributed by Victor Stinner in :issue:`38644` and :issue:`39542`.)
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* The :c:func:`PyModule_AddType` function is added to help adding a type
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to a module.
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(Contributed by Dong-hee Na in :issue:`40024`.)
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* Add the functions :c:func:`PyObject_GC_IsTracked` and
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:c:func:`PyObject_GC_IsFinalized` to the public API to allow to query if
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Python objects are being currently tracked or have been already finalized by
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the garbage collector respectively. (Contributed by Pablo Galindo in
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:issue:`40241`.)
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Porting to Python 3.9
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---------------------
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* ``PyInterpreterState.eval_frame`` (:pep:`523`) now requires a new mandatory
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*tstate* parameter (``PyThreadState*``).
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(Contributed by Victor Stinner in :issue:`38500`.)
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* Extension modules: :c:member:`~PyModuleDef.m_traverse`,
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:c:member:`~PyModuleDef.m_clear` and :c:member:`~PyModuleDef.m_free`
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functions of :c:type:`PyModuleDef` are no longer called if the module state
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was requested but is not allocated yet. This is the case immediately after
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the module is created and before the module is executed
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(:c:data:`Py_mod_exec` function). More precisely, these functions are not called
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if :c:member:`~PyModuleDef.m_size` is greater than 0 and the module state (as
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returned by :c:func:`PyModule_GetState`) is ``NULL``.
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Extension modules without module state (``m_size <= 0``) are not affected.
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* If :c:func:`Py_AddPendingCall` is called in a subinterpreter, the function is
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now scheduled to be called from the subinterpreter, rather than being called
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from the main interpreter. Each subinterpreter now has its own list of
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scheduled calls.
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(Contributed by Victor Stinner in :issue:`39984`.)
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* The Windows registry is no longer used to initialize :data:`sys.path` when
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the ``-E`` option is used (if :c:member:`PyConfig.use_environment` is set to
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``0``). This is significant when embedding Python on Windows.
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(Contributed by Zackery Spytz in :issue:`8901`.)
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* The global variable :c:data:`PyStructSequence_UnnamedField` is now a constant
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and refers to a constant string.
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(Contributed by Serhiy Storchaka in :issue:`38650`.)
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Removed
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-------
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* Exclude ``PyFPE_START_PROTECT()`` and ``PyFPE_END_PROTECT()`` macros of
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``pyfpe.h`` from the limited C API.
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(Contributed by Victor Stinner in :issue:`38835`.)
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* The ``tp_print`` slot of :ref:`PyTypeObject <type-structs>` has been removed.
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It was used for printing objects to files in Python 2.7 and before. Since
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Python 3.0, it has been ignored and unused.
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(Contributed by Jeroen Demeyer in :issue:`36974`.)
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* Changes in the limited C API (if ``Py_LIMITED_API`` macro is defined):
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* Exclude the following functions from the limited C API:
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* ``_Py_CheckRecursionLimit``
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* ``_Py_NewReference()``
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* ``_Py_ForgetReference()``
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* ``_PyTraceMalloc_NewReference()``
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* ``_Py_GetRefTotal()``
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* The trashcan mechanism which never worked in the limited C API.
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* ``PyTrash_UNWIND_LEVEL``
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* ``Py_TRASHCAN_BEGIN_CONDITION``
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* ``Py_TRASHCAN_BEGIN``
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* ``Py_TRASHCAN_END``
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* ``Py_TRASHCAN_SAFE_BEGIN``
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* ``Py_TRASHCAN_SAFE_END``
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* Move following functions and definitions to the internal C API:
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* ``_PyDebug_PrintTotalRefs()``
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* ``_Py_PrintReferences()``
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* ``_Py_PrintReferenceAddresses()``
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* ``_Py_tracemalloc_config``
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* ``_Py_AddToAllObjects()`` (specific to ``Py_TRACE_REFS`` build)
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(Contributed by Victor Stinner in :issue:`38644` and :issue:`39542`.)
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* Remove ``_PyRuntime.getframe`` hook and remove ``_PyThreadState_GetFrame``
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macro which was an alias to ``_PyRuntime.getframe``. They were only exposed
|
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by the internal C API. Remove also ``PyThreadFrameGetter`` type.
|
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(Contributed by Victor Stinner in :issue:`39946`.)
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|
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* Remove the following functions from the C API. Call :c:func:`PyGC_Collect`
|
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explicitly to clear all free lists.
|
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(Contributed by Inada Naoki and Victor Stinner in :issue:`37340`,
|
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:issue:`38896` and :issue:`40428`.)
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* ``PyAsyncGen_ClearFreeLists()``
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* ``PyContext_ClearFreeList()``
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* ``PyDict_ClearFreeList()``
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* ``PyFloat_ClearFreeList()``
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* ``PyFrame_ClearFreeList()``
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* ``PyList_ClearFreeList()``
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* ``PyMethod_ClearFreeList()`` and ``PyCFunction_ClearFreeList()``:
|
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the free lists of bound method objects have been removed.
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* ``PySet_ClearFreeList()``: the set free list has been removed
|
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in Python 3.4.
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* ``PyTuple_ClearFreeList()``
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* ``PyUnicode_ClearFreeList()``: the Unicode free list has been removed in
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Python 3.3.
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|
|
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