nntplib

:class:`~nntplib.NNTP` and :class:`~nntplib.NNTP_SSL` now raise a :class:`ValueError`

if the given timeout for their constructor is zero to prevent the creation of

a non-blocking socket. (Contributed by Dong-hee Na in :issue:`39259`.)

Build and C API Changes

* New :c:func:`PyFrame_GetCode` function: get a frame code.

New :c:func:`PyFrame_GetBack` function: get the frame next outer frame.

(Contributed by Victor Stinner in :issue:`40421`.)

* Add :c:func:`PyFrame_GetLineNumber` to the limited C API.

(Contributed by Victor Stinner in :issue:`40421`.)

* New :c:func:`PyThreadState_GetInterpreter` and

:c:func:`PyInterpreterState_Get` functions to get the interpreter.

New :c:func:`PyThreadState_GetFrame` function to get the current frame of a

Python thread state.

New :c:func:`PyThreadState_GetID` function: get the unique identifier of a

Python thread state.

(Contributed by Victor Stinner in :issue:`39947`.)

* Add ``--with-platlibdir`` option to the ``configure`` script: name of the

platform-specific library directory, stored in the new :attr:`sys.platlibdir`

attribute. See :attr:`sys.platlibdir` attribute for more information.

(Contributed by Jan Matějek, Matěj Cepl, Charalampos Stratakis and Victor Stinner in :issue:`1294959`.)

* Add a new public :c:func:`PyObject_CallNoArgs` function to the C API, which

calls a callable Python object without any arguments. It is the most efficient

way to call a callable Python object without any argument.

(Contributed by Victor Stinner in :issue:`37194`.)

* The global variable :c:data:`PyStructSequence_UnnamedField` is now a constant

and refers to a constant string.

(Contributed by Serhiy Storchaka in :issue:`38650`.)

* Exclude ``PyFPE_START_PROTECT()`` and ``PyFPE_END_PROTECT()`` macros of

``pyfpe.h`` from ``Py_LIMITED_API`` (stable API).

(Contributed by Victor Stinner in :issue:`38835`.)

* The ``tp_print`` slot of :ref:`PyTypeObject <type-structs>` has been removed.

It was used for printing objects to files in Python 2.7 and before. Since

Python 3.0, it has been ignored and unused.

(Contributed by Jeroen Demeyer in :issue:`36974`.)

* On non-Windows platforms, the :c:func:`setenv` and :c:func:`unsetenv`

functions are now required to build Python.

(Contributed by Victor Stinner in :issue:`39395`.)

* The ``COUNT_ALLOCS`` special build macro has been removed.

(Contributed by Victor Stinner in :issue:`39489`.)

* Changes in the limited C API (if ``Py_LIMITED_API`` macro is defined):

* Provide :c:func:`Py_EnterRecursiveCall` and :c:func:`Py_LeaveRecursiveCall`

as regular functions for the limited API. Previously, there were defined as

macros, but these macros didn't compile with the limited C API which cannot

access ``PyThreadState.recursion_depth`` field (the structure is opaque in

the limited C API).

* Exclude the following functions from the limited C API:

* ``_Py_CheckRecursionLimit``

* ``_Py_NewReference()``

* ``_Py_ForgetReference()``

* ``_PyTraceMalloc_NewReference()``

* ``_Py_GetRefTotal()``

* The trashcan mechanism which never worked in the limited C API.

* ``PyTrash_UNWIND_LEVEL``

* ``Py_TRASHCAN_BEGIN_CONDITION``

* ``Py_TRASHCAN_BEGIN``

* ``Py_TRASHCAN_END``

* ``Py_TRASHCAN_SAFE_BEGIN``

* ``Py_TRASHCAN_SAFE_END``

* The following static inline functions or macros become regular "opaque"

function to hide implementation details:

* ``_Py_NewReference()``

* ``PyObject_INIT()`` and ``PyObject_INIT_VAR()`` become aliases to

:c:func:`PyObject_Init` and :c:func:`PyObject_InitVar` in the limited C

API, but are overriden with static inline function otherwise. Thanks to

that, it was possible to exclude ``_Py_NewReference()`` from the limited

C API.

* Move following functions and definitions to the internal C API:

* ``_PyDebug_PrintTotalRefs()``

* ``_Py_PrintReferences()``

* ``_Py_PrintReferenceAddresses()``

* ``_Py_tracemalloc_config``

* ``_Py_AddToAllObjects()`` (specific to ``Py_TRACE_REFS`` build)

(Contributed by Victor Stinner in :issue:`38644` and :issue:`39542`.)

* ``PyInterpreterState.eval_frame`` (:pep:`523`) now requires a new mandatory

*tstate* parameter (``PyThreadState*``).

(Contributed by Victor Stinner in :issue:`38500`.)

* Extension modules: :c:member:`~PyModuleDef.m_traverse`,

:c:member:`~PyModuleDef.m_clear` and :c:member:`~PyModuleDef.m_free`

functions of :c:type:`PyModuleDef` are no longer called if the module state

was requested but is not allocated yet. This is the case immediately after

the module is created and before the module is executed

(:c:data:`Py_mod_exec` function). More precisely, these functions are not called

if :c:member:`~PyModuleDef.m_size` is greater than 0 and the module state (as

returned by :c:func:`PyModule_GetState`) is ``NULL``.

Extension modules without module state (``m_size <= 0``) are not affected.

* If :c:func:`Py_AddPendingCall` is called in a subinterpreter, the function is

now scheduled to be called from the subinterpreter, rather than being called

from the main interpreter. Each subinterpreter now has its own list of

scheduled calls.

(Contributed by Victor Stinner in :issue:`39984`.)

* Remove ``_PyRuntime.getframe`` hook and remove ``_PyThreadState_GetFrame``

macro which was an alias to ``_PyRuntime.getframe``. They were only exposed

by the internal C API. Remove also ``PyThreadFrameGetter`` type.

(Contributed by Victor Stinner in :issue:`39946`.)

* The :c:func:`PyModule_AddType` function is added to help adding a type to a module.

(Contributed by Dong-hee Na in :issue:`40024`.)

* The Windows registry is no longer used to initialize :data:`sys.path` when

the ``-E`` option is used. This is significant when embedding Python on

Windows.

(Contributed by Zackery Spytz in :issue:`8901`.)

* Add the functions :c:func:`PyObject_GC_IsTracked` and

:c:func:`PyObject_GC_IsFinalized` to the public API to allow to query if

Python objects are being currently tracked or have been already finalized by

the garbage collector respectively. (Contributed by Pablo Galindo in

:issue:`40241`.)

* Remove the following functions from the C API. Call :c:func:`PyGC_Collect`

explicitly to clear all free lists.

(Contributed by Inada Naoki and Victor Stinner in :issue:`37340`,

:issue:`38896` and :issue:`40428`.)

* ``PyAsyncGen_ClearFreeLists()``

* ``PyContext_ClearFreeList()``

* ``PyDict_ClearFreeList()``

* ``PyFloat_ClearFreeList()``

* ``PyFrame_ClearFreeList()``

* ``PyList_ClearFreeList()``

* ``PyMethod_ClearFreeList()`` and ``PyCFunction_ClearFreeList()``:

the free lists of bound method objects have been removed.

* ``PySet_ClearFreeList()``: the set free list has been removed

in Python 3.4.

* ``PyTuple_ClearFreeList()``

* ``PyUnicode_ClearFreeList()``: the Unicode free list has been removed in

Python 3.3.

* binhex4 and hexbin4 standards are now deprecated. The :`binhex` module