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Oct 24, 2022
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gh-95913: Edit, link and sort 3.11 WhatsNew Build section #98588

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be26e05
Fix and improve Sphinx syntax & grammar/phrasing in Build section
CAM-Gerlach Oct 24, 2022
8dd1575
Organize Build section by topic and consolidate duplicative entries
CAM-Gerlach Oct 24, 2022
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124 changes: 67 additions & 57 deletions Doc/whatsnew/3.11.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -1818,31 +1818,66 @@ Porting notes for the C API are
Build Changes
=============

* Building Python now requires a C11 compiler. Optional C11 features are not
required.
(Contributed by Victor Stinner in :issue:`46656`.)

* Building Python now requires support of IEEE 754 floating point numbers.
(Contributed by Victor Stinner in :issue:`46917`.)
* CPython now has :pep:`11` :pep:`Tier 3 support <11#tier-3>` for
cross compiling to the `WebAssembly <https://webassembly.org/>`_ platforms
`Emscripten <https://emscripten.org/>`_
(``wasm32-unknown-emscripten``, i.e. Python in the browser)
and `WebAssembly System Interface (WASI) <https://wasi.dev/>`_
(``wasm32-unknown-wasi``).
The effort is inspired by previous work like `Pyodide <https://pyodide.org/>`_.
These platforms provide a limited subset of POSIX APIs; Python standard
libraries features and modules related to networking, processes, threading,
signals, mmap, and users/groups are not available or don't work.
(Emscripten contributed by Christian Heimes and Ethan Smith in :gh:`84461`
and WASI contributed by Christian Heimes in :gh:`90473`;
platforms promoted in :gh:`95085`)

* Building Python now requires:

* A `C11 <https://en.cppreference.com/w/c/11>`_ compiler.
`Optional C11 features
<https://en.wikipedia.org/wiki/C11_(C_standard_revision)#Optional_features>`_
are not required.
(Contributed by Victor Stinner in :issue:`46656`.)

* Support for `IEEE 754 <https://en.wikipedia.org/wiki/IEEE_754>`_
floating point numbers.
(Contributed by Victor Stinner in :issue:`46917`.)

* Support for `floating point Not-a-Number (NaN)
<https://en.wikipedia.org/wiki/NaN#Floating_point>`_,
as the :c:macro:`!Py_NO_NAN` macro has been removed.
(Contributed by Victor Stinner in :issue:`46656`.)

* A `C99 <https://en.cppreference.com/w/c/99>`_
``<math.h>`` header file providing the
:c:func:`!copysign`, :c:func:`!hypot`, :c:func:`!isfinite`,
:c:func:`!isinf`, :c:func:`!isnan`, and :c:func:`!round` functions
(contributed by Victor Stinner in :issue:`45440`);
and a :c:data:`!NAN` constant or the :c:func:`!__builtin_nan` function
(Contributed by Victor Stinner in :issue:`46640`).
Comment on lines +1835 to +1858
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  • NaNs are part of IEEE 754, and the math functions are part of C11, so mentioning the earlier changes are redundant now.
  • This is specific to CPython.
Suggested change
* Building Python now requires:
* A `C11 <https://en.cppreference.com/w/c/11>`_ compiler.
`Optional C11 features
<https://en.wikipedia.org/wiki/C11_(C_standard_revision)#Optional_features>`_
are not required.
(Contributed by Victor Stinner in :issue:`46656`.)
* Support for `IEEE 754 <https://en.wikipedia.org/wiki/IEEE_754>`_
floating point numbers.
(Contributed by Victor Stinner in :issue:`46917`.)
* Support for `floating point Not-a-Number (NaN)
<https://en.wikipedia.org/wiki/NaN#Floating_point>`_,
as the :c:macro:`!Py_NO_NAN` macro has been removed.
(Contributed by Victor Stinner in :issue:`46656`.)
* A `C99 <https://en.cppreference.com/w/c/99>`_
``<math.h>`` header file providing the
:c:func:`!copysign`, :c:func:`!hypot`, :c:func:`!isfinite`,
:c:func:`!isinf`, :c:func:`!isnan`, and :c:func:`!round` functions
(contributed by Victor Stinner in :issue:`45440`);
and a :c:data:`!NAN` constant or the :c:func:`!__builtin_nan` function
(Contributed by Victor Stinner in :issue:`46640`).
* Building CPython now requires:
* A `C11 <https://en.cppreference.com/w/c/11>`_ compiler and standard library.
`Optional C11 features
<https://en.wikipedia.org/wiki/C11_(C_standard_revision)#Optional_features>`_
are not required.
(Contributed by Victor Stinner in :issue:`46656`,
:issue:`45440`, :issue:`46640`.)
* Support for `IEEE 754 <https://en.wikipedia.org/wiki/IEEE_754>`_
floating point numbers.
(Contributed by Victor Stinner in :issue:`46917`.)
* The :c:macro:`!Py_NO_NAN` macro has been removed.
Since CPython now requires IEEE 754 floats, NaN values are always available.
(Contributed by Victor Stinner in :issue:`46656`.)

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Ah, too late. No big deal.

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Sorry about that. I was wondering about it, but I wanted to be conservative with my initial changes since I wasn't 100% sure. I can submit a PR for you (with you co-authored on the commit) to apply it going forward, or you can if you prefer.

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Go ahead. I might get to it later, as my task list shrinks.

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Wait, your task list actually shrinks? It seems as if by invisible dark energy that my task list is perpetually expanding...

In any case, I went ahead and opened this as PR #98781, thanks.


* The :mod:`tkinter` package now requires `Tcl/Tk <https://www.tcl.tk>`_
version 8.5.12 or newer.
(Contributed by Serhiy Storchaka in :issue:`46996`.)

* CPython can now be built with the ThinLTO option via ``--with-lto=thin``.
(Contributed by Dong-hee Na and Brett Holman in :issue:`44340`.)
* Build dependencies, compiler flags, and linker flags for most stdlib
extension modules are now detected by :program:`configure`. libffi, libnsl,
libsqlite3, zlib, bzip2, liblzma, libcrypt, Tcl/Tk, and uuid flags
are detected by `pkg-config
<https://www.freedesktop.org/wiki/Software/pkg-config/>`_ (when available).
:mod:`tkinter` now requires a pkg-config command
to detect development settings for `Tcl/Tk`_ headers and libraries.
(Contributed by Christian Heimes and Erlend Egeberg Aasland in
:issue:`45847`, :issue:`45747`, and :issue:`45763`.)

* libpython is no longer linked against libcrypt.
(Contributed by Mike Gilbert in :issue:`45433`.)

* Building Python now requires a C99 ``<math.h>`` header file providing
the following functions: ``copysign()``, ``hypot()``, ``isfinite()``,
``isinf()``, ``isnan()``, ``round()``.
(Contributed by Victor Stinner in :issue:`45440`.)

* Building Python now requires a C99 ``<math.h>`` header file providing
a ``NAN`` constant, or the ``__builtin_nan()`` built-in function.
(Contributed by Victor Stinner in :issue:`46640`.)

* Building Python now requires support for floating point Not-a-Number (NaN):
remove the ``Py_NO_NAN`` macro.
(Contributed by Victor Stinner in :issue:`46656`.)
* CPython can now be built with the
`ThinLTO <https://clang.llvm.org/docs/ThinLTO.html>`_ option
via passing ``thin`` to :option:`--with-lto`, i.e. ``--with-lto=thin``.
(Contributed by Dong-hee Na and Brett Holman in :issue:`44340`.)

* Freelists for object structs can now be disabled. A new :program:`configure`
option :option:`!--without-freelists` can be used to disable all freelists
Expand All @@ -1851,55 +1886,30 @@ Build Changes

* ``Modules/Setup`` and ``Modules/makesetup`` have been improved and tied up.
Extension modules can now be built through ``makesetup``. All except some
test modules can be linked statically into main binary or library.
test modules can be linked statically into a main binary or library.
(Contributed by Brett Cannon and Christian Heimes in :issue:`45548`,
:issue:`45570`, :issue:`45571`, and :issue:`43974`.)

* Build dependencies, compiler flags, and linker flags for most stdlib
extension modules are now detected by :program:`configure`. libffi, libnsl,
libsqlite3, zlib, bzip2, liblzma, libcrypt, Tcl/Tk, and uuid flags
are detected by ``pkg-config`` (when available). :mod:`tkinter` now
requires ``pkg-config`` command to detect development settings for Tcl/Tk
headers and libraries.
(Contributed by Christian Heimes and Erlend Egeberg Aasland in
:issue:`45847`, :issue:`45747`, and :issue:`45763`.)

.. note::
Use the environment variables :envvar:`TCLTK_CFLAGS` and
:envvar:`TCLTK_LIBS` to manually specify the location of Tcl/Tk headers
and libraries. The :program:`configure` options ``--with-tcltk-includes``
and ``--with-tcltk-libs`` have been removed.
Use the environment variables :envvar:`!TCLTK_CFLAGS` and
:envvar:`!TCLTK_LIBS` to manually specify the location of Tcl/Tk headers
and libraries. The :program:`configure` options
:option:`!--with-tcltk-includes` and :option:`!--with-tcltk-libs`
have been removed.

On RHEL 7 and CentOS 7 the development packages do not provide ``tcl.pc``
and ``tk.pc``, use :envvar:`TCLTK_LIBS="-ltk8.5 -ltkstub8.5 -ltcl8.5"`.
and ``tk.pc``; use ``TCLTK_LIBS="-ltk8.5 -ltkstub8.5 -ltcl8.5"``.
The directory ``Misc/rhel7`` contains ``.pc`` files and instructions
how to build Python with RHEL 7's and CentOS 7's Tcl/Tk and OpenSSL.

* CPython now has :pep:`11` tier 3 support for cross compiling to WebAssembly
platform ``wasm32-unknown-emscripten`` (Python in the browser). The effort
is inspired by previous work like `Pyodide <https://pyodide.org/>`_.
Emscripten provides a limited subset of POSIX APIs. Python standard
libraries features and modules related to networking, processes, threading,
signals, mmap, and users/groups are not available or don't work.
(Contributed by Christian Heimes and Ethan Smith in :gh:`84461`,
promoted in :gh:`95085`)

* CPython now has :pep:`11` tier 3 support for cross compiling to WebAssembly
platform ``wasm32-unknown-wasi`` (WebAssembly System Interface). Like on
Emscripten, only a subset of Python's standard library is available on WASI.
(Contributed by Christian Heimes in :gh:`90473`, promoted in :gh:`95085`)
on how to build Python with RHEL 7's and CentOS 7's Tcl/Tk and OpenSSL.

* CPython will now use 30-bit digits by default for the Python :class:`int`
implementation. Previously, the default was to use 30-bit digits on platforms
with ``SIZEOF_VOID_P >= 8``, and 15-bit digits otherwise. It's still possible
to explicitly request use of 15-bit digits via either the
``--enable-big-digits`` option to the configure script or (for Windows) the
``PYLONG_BITS_IN_DIGIT`` variable in ``PC/pyconfig.h``, but this option may
be removed at some point in the future. (Contributed by Mark Dickinson in
:issue:`45569`.)

* The :mod:`tkinter` package now requires Tcl/Tk version 8.5.12 or newer.
(Contributed by Serhiy Storchaka in :issue:`46996`.)
:option:`--enable-big-digits` option to the configure script
or (for Windows) the ``PYLONG_BITS_IN_DIGIT`` variable in ``PC/pyconfig.h``,
but this option may be removed at some point in the future.
(Contributed by Mark Dickinson in :issue:`45569`.)


.. _whatsnew311-c-api:
Expand Down