mirror of https://github.com/python/cpython
1014 lines
28 KiB
ReStructuredText
1014 lines
28 KiB
ReStructuredText
****************
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Configure Python
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****************
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Build Requirements
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==================
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Features required to build CPython:
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* A `C11 <https://en.cppreference.com/w/c/11>`_ compiler. `Optional C11
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features
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<https://en.wikipedia.org/wiki/C11_(C_standard_revision)#Optional_features>`_
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are not required.
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* Support for `IEEE 754 <https://en.wikipedia.org/wiki/IEEE_754>`_ floating
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point numbers and `floating point Not-a-Number (NaN)
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<https://en.wikipedia.org/wiki/NaN#Floating_point>`_.
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* Support for threads.
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* OpenSSL 1.1.1 or newer for the :mod:`ssl` and :mod:`hashlib` modules.
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* On Windows, Microsoft Visual Studio 2017 or later is required.
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.. versionchanged:: 3.11
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C11 compiler, IEEE 754 and NaN support are now required.
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On Windows, Visual Studio 2017 or later is required.
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.. versionchanged:: 3.10
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OpenSSL 1.1.1 is now required.
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.. versionchanged:: 3.7
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Thread support and OpenSSL 1.0.2 are now required.
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.. versionchanged:: 3.6
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Selected C99 features are now required, like ``<stdint.h>`` and ``static
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inline`` functions.
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.. versionchanged:: 3.5
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On Windows, Visual Studio 2015 or later is required.
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See also :pep:`7` "Style Guide for C Code" and :pep:`11` "CPython platform
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support".
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.. _configure-options:
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Configure Options
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=================
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List all ``./configure`` script options using::
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./configure --help
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See also the :file:`Misc/SpecialBuilds.txt` in the Python source distribution.
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General Options
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---------------
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.. cmdoption:: --enable-loadable-sqlite-extensions
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Support loadable extensions in the :mod:`_sqlite` extension module (default
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is no).
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See the :meth:`sqlite3.Connection.enable_load_extension` method of the
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:mod:`sqlite3` module.
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.. versionadded:: 3.6
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.. cmdoption:: --disable-ipv6
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Disable IPv6 support (enabled by default if supported), see the
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:mod:`socket` module.
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.. cmdoption:: --enable-big-digits=[15|30]
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Define the size in bits of Python :class:`int` digits: 15 or 30 bits.
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By default, the digit size is 30.
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Define the ``PYLONG_BITS_IN_DIGIT`` to ``15`` or ``30``.
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See :data:`sys.int_info.bits_per_digit <sys.int_info>`.
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.. cmdoption:: --with-suffix=SUFFIX
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Set the Python executable suffix to *SUFFIX*.
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The default suffix is ``.exe`` on Windows and macOS (``python.exe``
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executable), ``.js`` on Emscripten node, ``.html`` on Emscripten browser,
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``.wasm`` on WASI, and an empty string on other platforms (``python``
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executable).
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.. versionchanged:: 3.11
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The default suffix on WASM platform is one of ``.js``, ``.html``
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or ``.wasm``.
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.. cmdoption:: --with-tzpath=<list of absolute paths separated by pathsep>
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Select the default time zone search path for :data:`zoneinfo.TZPATH`.
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See the :ref:`Compile-time configuration
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<zoneinfo_data_compile_time_config>` of the :mod:`zoneinfo` module.
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Default: ``/usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo``.
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See :data:`os.pathsep` path separator.
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.. versionadded:: 3.9
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.. cmdoption:: --without-decimal-contextvar
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Build the ``_decimal`` extension module using a thread-local context rather
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than a coroutine-local context (default), see the :mod:`decimal` module.
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See :data:`decimal.HAVE_CONTEXTVAR` and the :mod:`contextvars` module.
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.. versionadded:: 3.9
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.. cmdoption:: --with-dbmliborder=<list of backend names>
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Override order to check db backends for the :mod:`dbm` module
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A valid value is a colon (``:``) separated string with the backend names:
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* ``ndbm``;
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* ``gdbm``;
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* ``bdb``.
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.. cmdoption:: --without-c-locale-coercion
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Disable C locale coercion to a UTF-8 based locale (enabled by default).
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Don't define the ``PY_COERCE_C_LOCALE`` macro.
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See :envvar:`PYTHONCOERCECLOCALE` and the :pep:`538`.
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.. cmdoption:: --without-freelists
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Disable all freelists except the empty tuple singleton.
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.. versionadded:: 3.11
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.. cmdoption:: --with-platlibdir=DIRNAME
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Python library directory name (default is ``lib``).
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Fedora and SuSE use ``lib64`` on 64-bit platforms.
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See :data:`sys.platlibdir`.
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.. versionadded:: 3.9
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.. cmdoption:: --with-wheel-pkg-dir=PATH
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Directory of wheel packages used by the :mod:`ensurepip` module
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(none by default).
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Some Linux distribution packaging policies recommend against bundling
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dependencies. For example, Fedora installs wheel packages in the
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``/usr/share/python-wheels/`` directory and don't install the
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:mod:`ensurepip._bundled` package.
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.. versionadded:: 3.10
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.. cmdoption:: --with-pkg-config=[check|yes|no]
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Whether configure should use :program:`pkg-config` to detect build
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dependencies.
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* ``check`` (default): :program:`pkg-config` is optional
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* ``yes``: :program:`pkg-config` is mandatory
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* ``no``: configure does not use :program:`pkg-config` even when present
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.. versionadded:: 3.11
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.. cmdoption:: --enable-pystats
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Turn on internal statistics gathering.
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The statistics will be dumped to a arbitrary (probably unique) file in
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``/tmp/py_stats/``, or ``C:\temp\py_stats\`` on Windows. If that directory
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does not exist, results will be printed on stdout.
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Use ``Tools/scripts/summarize_stats.py`` to read the stats.
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.. versionadded:: 3.11
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WebAssembly Options
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-------------------
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.. cmdoption:: --with-emscripten-target=[browser|node]
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Set build flavor for ``wasm32-emscripten``.
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* ``browser`` (default): preload minimal stdlib, default MEMFS.
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* ``node``: NODERAWFS and pthread support.
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.. versionadded:: 3.11
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.. cmdoption:: --enable-wasm-dynamic-linking
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Turn on dynamic linking support for WASM.
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Dynamic linking enables ``dlopen``. File size of the executable
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increases due to limited dead code elimination and additional features.
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.. versionadded:: 3.11
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.. cmdoption:: --enable-wasm-pthreads
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Turn on pthreads support for WASM.
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.. versionadded:: 3.11
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Install Options
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---------------
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.. cmdoption:: --prefix=PREFIX
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Install architecture-independent files in PREFIX. On Unix, it
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defaults to :file:`/usr/local`.
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This value can be retrived at runtime using :data:`sys.prefix`.
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As an example, one can use ``--prefix="$HOME/.local/"`` to install
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a Python in its home directory.
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.. cmdoption:: --exec-prefix=EPREFIX
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Install architecture-dependent files in EPREFIX, defaults to :option:`--prefix`.
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This value can be retrived at runtime using :data:`sys.exec_prefix`.
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.. cmdoption:: --disable-test-modules
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Don't build nor install test modules, like the :mod:`test` package or the
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:mod:`_testcapi` extension module (built and installed by default).
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.. versionadded:: 3.10
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.. cmdoption:: --with-ensurepip=[upgrade|install|no]
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Select the :mod:`ensurepip` command run on Python installation:
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* ``upgrade`` (default): run ``python -m ensurepip --altinstall --upgrade``
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command.
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* ``install``: run ``python -m ensurepip --altinstall`` command;
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* ``no``: don't run ensurepip;
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.. versionadded:: 3.6
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Performance options
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-------------------
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Configuring Python using ``--enable-optimizations --with-lto`` (PGO + LTO) is
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recommended for best performance. The experimental ``--enable-bolt`` flag can
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also be used to improve performance.
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.. cmdoption:: --enable-optimizations
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Enable Profile Guided Optimization (PGO) using :envvar:`PROFILE_TASK`
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(disabled by default).
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The C compiler Clang requires ``llvm-profdata`` program for PGO. On
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macOS, GCC also requires it: GCC is just an alias to Clang on macOS.
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Disable also semantic interposition in libpython if ``--enable-shared`` and
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GCC is used: add ``-fno-semantic-interposition`` to the compiler and linker
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flags.
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.. versionadded:: 3.6
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.. versionchanged:: 3.10
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Use ``-fno-semantic-interposition`` on GCC.
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.. envvar:: PROFILE_TASK
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Environment variable used in the Makefile: Python command line arguments for
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the PGO generation task.
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Default: ``-m test --pgo --timeout=$(TESTTIMEOUT)``.
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.. versionadded:: 3.8
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.. cmdoption:: --with-lto=[full|thin|no|yes]
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Enable Link Time Optimization (LTO) in any build (disabled by default).
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The C compiler Clang requires ``llvm-ar`` for LTO (``ar`` on macOS), as well
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as an LTO-aware linker (``ld.gold`` or ``lld``).
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.. versionadded:: 3.6
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.. versionadded:: 3.11
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To use ThinLTO feature, use ``--with-lto=thin`` on Clang.
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.. versionchanged:: 3.12
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Use ThinLTO as the default optimization policy on Clang if the compiler accepts the flag.
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.. cmdoption:: --enable-bolt
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Enable usage of the `BOLT post-link binary optimizer
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<https://github.com/llvm/llvm-project/tree/main/bolt>`_ (disabled by
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default).
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BOLT is part of the LLVM project but is not always included in their binary
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distributions. This flag requires that ``llvm-bolt`` and ``merge-fdata``
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are available.
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BOLT is still a fairly new project so this flag should be considered
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experimental for now. Because this tool operates on machine code its success
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is dependent on a combination of the build environment + the other
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optimization configure args + the CPU architecture, and not all combinations
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are supported.
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BOLT versions before LLVM 16 are known to crash BOLT under some scenarios.
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Use of LLVM 16 or newer for BOLT optimization is strongly encouraged.
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The :envvar:`!BOLT_INSTRUMENT_FLAGS` and :envvar:`!BOLT_APPLY_FLAGS`
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:program:`configure` variables can be defined to override the default set of
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arguments for :program:`llvm-bolt` to instrument and apply BOLT data to
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binaries, respectively.
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.. versionadded:: 3.12
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.. cmdoption:: --with-computed-gotos
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Enable computed gotos in evaluation loop (enabled by default on supported
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compilers).
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.. cmdoption:: --without-pymalloc
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Disable the specialized Python memory allocator :ref:`pymalloc <pymalloc>`
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(enabled by default).
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See also :envvar:`PYTHONMALLOC` environment variable.
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.. cmdoption:: --without-doc-strings
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Disable static documentation strings to reduce the memory footprint (enabled
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by default). Documentation strings defined in Python are not affected.
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Don't define the ``WITH_DOC_STRINGS`` macro.
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See the ``PyDoc_STRVAR()`` macro.
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.. cmdoption:: --enable-profiling
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Enable C-level code profiling with ``gprof`` (disabled by default).
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.. cmdoption:: --with-strict-overflow
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Add ``-fstrict-overflow`` to the C compiler flags (by default we add
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``-fno-strict-overflow`` instead).
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.. _debug-build:
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Python Debug Build
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------------------
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A debug build is Python built with the :option:`--with-pydebug` configure
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option.
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Effects of a debug build:
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* Display all warnings by default: the list of default warning filters is empty
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in the :mod:`warnings` module.
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* Add ``d`` to :data:`sys.abiflags`.
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* Add :func:`sys.gettotalrefcount` function.
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* Add :option:`-X showrefcount <-X>` command line option.
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* Add :option:`-d` command line option and :envvar:`PYTHONDEBUG` environment
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variable to debug the parser.
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* Add support for the ``__lltrace__`` variable: enable low-level tracing in the
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bytecode evaluation loop if the variable is defined.
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* Install :ref:`debug hooks on memory allocators <default-memory-allocators>`
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to detect buffer overflow and other memory errors.
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* Define ``Py_DEBUG`` and ``Py_REF_DEBUG`` macros.
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* Add runtime checks: code surrounded by ``#ifdef Py_DEBUG`` and ``#endif``.
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Enable ``assert(...)`` and ``_PyObject_ASSERT(...)`` assertions: don't set
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the ``NDEBUG`` macro (see also the :option:`--with-assertions` configure
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option). Main runtime checks:
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* Add sanity checks on the function arguments.
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* Unicode and int objects are created with their memory filled with a pattern
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to detect usage of uninitialized objects.
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* Ensure that functions which can clear or replace the current exception are
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not called with an exception raised.
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* Check that deallocator functions don't change the current exception.
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* The garbage collector (:func:`gc.collect` function) runs some basic checks
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on objects consistency.
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* The :c:macro:`Py_SAFE_DOWNCAST()` macro checks for integer underflow and
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overflow when downcasting from wide types to narrow types.
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See also the :ref:`Python Development Mode <devmode>` and the
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:option:`--with-trace-refs` configure option.
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.. versionchanged:: 3.8
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Release builds and debug builds are now ABI compatible: defining the
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``Py_DEBUG`` macro no longer implies the ``Py_TRACE_REFS`` macro (see the
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:option:`--with-trace-refs` option), which introduces the only ABI
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incompatibility.
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Debug options
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-------------
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.. cmdoption:: --with-pydebug
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:ref:`Build Python in debug mode <debug-build>`: define the ``Py_DEBUG``
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macro (disabled by default).
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.. cmdoption:: --with-trace-refs
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Enable tracing references for debugging purpose (disabled by default).
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Effects:
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* Define the ``Py_TRACE_REFS`` macro.
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* Add :func:`sys.getobjects` function.
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* Add :envvar:`PYTHONDUMPREFS` environment variable.
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This build is not ABI compatible with release build (default build) or debug
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build (``Py_DEBUG`` and ``Py_REF_DEBUG`` macros).
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.. versionadded:: 3.8
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.. cmdoption:: --with-assertions
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Build with C assertions enabled (default is no): ``assert(...);`` and
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``_PyObject_ASSERT(...);``.
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If set, the ``NDEBUG`` macro is not defined in the :envvar:`OPT` compiler
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variable.
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See also the :option:`--with-pydebug` option (:ref:`debug build
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<debug-build>`) which also enables assertions.
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.. versionadded:: 3.6
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.. cmdoption:: --with-valgrind
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Enable Valgrind support (default is no).
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.. cmdoption:: --with-dtrace
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Enable DTrace support (default is no).
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See :ref:`Instrumenting CPython with DTrace and SystemTap
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<instrumentation>`.
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.. versionadded:: 3.6
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.. cmdoption:: --with-address-sanitizer
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Enable AddressSanitizer memory error detector, ``asan`` (default is no).
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.. versionadded:: 3.6
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.. cmdoption:: --with-memory-sanitizer
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Enable MemorySanitizer allocation error detector, ``msan`` (default is no).
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.. versionadded:: 3.6
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.. cmdoption:: --with-undefined-behavior-sanitizer
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Enable UndefinedBehaviorSanitizer undefined behaviour detector, ``ubsan``
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(default is no).
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.. versionadded:: 3.6
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Linker options
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--------------
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.. cmdoption:: --enable-shared
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Enable building a shared Python library: ``libpython`` (default is no).
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.. cmdoption:: --without-static-libpython
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Do not build ``libpythonMAJOR.MINOR.a`` and do not install ``python.o``
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(built and enabled by default).
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.. versionadded:: 3.10
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Libraries options
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-----------------
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.. cmdoption:: --with-libs='lib1 ...'
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Link against additional libraries (default is no).
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.. cmdoption:: --with-system-expat
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Build the :mod:`pyexpat` module using an installed ``expat`` library
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(default is no).
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.. cmdoption:: --with-system-libmpdec
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Build the ``_decimal`` extension module using an installed ``mpdec``
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library, see the :mod:`decimal` module (default is no).
|
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.. versionadded:: 3.3
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.. cmdoption:: --with-readline=editline
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Use ``editline`` library for backend of the :mod:`readline` module.
|
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Define the ``WITH_EDITLINE`` macro.
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.. versionadded:: 3.10
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.. cmdoption:: --without-readline
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Don't build the :mod:`readline` module (built by default).
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Don't define the ``HAVE_LIBREADLINE`` macro.
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.. versionadded:: 3.10
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.. cmdoption:: --with-libm=STRING
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Override ``libm`` math library to *STRING* (default is system-dependent).
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.. cmdoption:: --with-libc=STRING
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Override ``libc`` C library to *STRING* (default is system-dependent).
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.. cmdoption:: --with-openssl=DIR
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Root of the OpenSSL directory.
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.. versionadded:: 3.7
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.. cmdoption:: --with-openssl-rpath=[no|auto|DIR]
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Set runtime library directory (rpath) for OpenSSL libraries:
|
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* ``no`` (default): don't set rpath;
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* ``auto``: auto-detect rpath from :option:`--with-openssl` and
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``pkg-config``;
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* *DIR*: set an explicit rpath.
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.. versionadded:: 3.10
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Security Options
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|
----------------
|
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.. cmdoption:: --with-hash-algorithm=[fnv|siphash13|siphash24]
|
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Select hash algorithm for use in ``Python/pyhash.c``:
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* ``siphash13`` (default);
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* ``siphash24``;
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* ``fnv``.
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.. versionadded:: 3.4
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|
|
.. versionadded:: 3.11
|
|
``siphash13`` is added and it is the new default.
|
|
|
|
.. cmdoption:: --with-builtin-hashlib-hashes=md5,sha1,sha256,sha512,sha3,blake2
|
|
|
|
Built-in hash modules:
|
|
|
|
* ``md5``;
|
|
* ``sha1``;
|
|
* ``sha256``;
|
|
* ``sha512``;
|
|
* ``sha3`` (with shake);
|
|
* ``blake2``.
|
|
|
|
.. versionadded:: 3.9
|
|
|
|
.. cmdoption:: --with-ssl-default-suites=[python|openssl|STRING]
|
|
|
|
Override the OpenSSL default cipher suites string:
|
|
|
|
* ``python`` (default): use Python's preferred selection;
|
|
* ``openssl``: leave OpenSSL's defaults untouched;
|
|
* *STRING*: use a custom string
|
|
|
|
See the :mod:`ssl` module.
|
|
|
|
.. versionadded:: 3.7
|
|
|
|
.. versionchanged:: 3.10
|
|
|
|
The settings ``python`` and *STRING* also set TLS 1.2 as minimum
|
|
protocol version.
|
|
|
|
macOS Options
|
|
-------------
|
|
|
|
See ``Mac/README.rst``.
|
|
|
|
.. cmdoption:: --enable-universalsdk
|
|
.. cmdoption:: --enable-universalsdk=SDKDIR
|
|
|
|
Create a universal binary build. *SDKDIR* specifies which macOS SDK should
|
|
be used to perform the build (default is no).
|
|
|
|
.. cmdoption:: --enable-framework
|
|
.. cmdoption:: --enable-framework=INSTALLDIR
|
|
|
|
Create a Python.framework rather than a traditional Unix install. Optional
|
|
*INSTALLDIR* specifies the installation path (default is no).
|
|
|
|
.. cmdoption:: --with-universal-archs=ARCH
|
|
|
|
Specify the kind of universal binary that should be created. This option is
|
|
only valid when :option:`--enable-universalsdk` is set.
|
|
|
|
Options:
|
|
|
|
* ``universal2``;
|
|
* ``32-bit``;
|
|
* ``64-bit``;
|
|
* ``3-way``;
|
|
* ``intel``;
|
|
* ``intel-32``;
|
|
* ``intel-64``;
|
|
* ``all``.
|
|
|
|
.. cmdoption:: --with-framework-name=FRAMEWORK
|
|
|
|
Specify the name for the python framework on macOS only valid when
|
|
:option:`--enable-framework` is set (default: ``Python``).
|
|
|
|
|
|
Cross Compiling Options
|
|
-----------------------
|
|
|
|
Cross compiling, also known as cross building, can be used to build Python
|
|
for another CPU architecture or platform. Cross compiling requires a Python
|
|
interpreter for the build platform. The version of the build Python must match
|
|
the version of the cross compiled host Python.
|
|
|
|
.. cmdoption:: --build=BUILD
|
|
|
|
configure for building on BUILD, usually guessed by :program:`config.guess`.
|
|
|
|
.. cmdoption:: --host=HOST
|
|
|
|
cross-compile to build programs to run on HOST (target platform)
|
|
|
|
.. cmdoption:: --with-build-python=path/to/python
|
|
|
|
path to build ``python`` binary for cross compiling
|
|
|
|
.. versionadded:: 3.11
|
|
|
|
.. cmdoption:: CONFIG_SITE=file
|
|
|
|
An environment variable that points to a file with configure overrides.
|
|
|
|
Example *config.site* file::
|
|
|
|
# config.site-aarch64
|
|
ac_cv_buggy_getaddrinfo=no
|
|
ac_cv_file__dev_ptmx=yes
|
|
ac_cv_file__dev_ptc=no
|
|
|
|
|
|
Cross compiling example::
|
|
|
|
CONFIG_SITE=config.site-aarch64 ../configure \
|
|
--build=x86_64-pc-linux-gnu \
|
|
--host=aarch64-unknown-linux-gnu \
|
|
--with-build-python=../x86_64/python
|
|
|
|
|
|
Python Build System
|
|
===================
|
|
|
|
Main files of the build system
|
|
------------------------------
|
|
|
|
* :file:`configure.ac` => :file:`configure`;
|
|
* :file:`Makefile.pre.in` => :file:`Makefile` (created by :file:`configure`);
|
|
* :file:`pyconfig.h` (created by :file:`configure`);
|
|
* :file:`Modules/Setup`: C extensions built by the Makefile using
|
|
:file:`Module/makesetup` shell script;
|
|
* :file:`setup.py`: C extensions built using the ``setuptools`` package.
|
|
|
|
Main build steps
|
|
----------------
|
|
|
|
* C files (``.c``) are built as object files (``.o``).
|
|
* A static ``libpython`` library (``.a``) is created from objects files.
|
|
* ``python.o`` and the static ``libpython`` library are linked into the
|
|
final ``python`` program.
|
|
* C extensions are built by the Makefile (see :file:`Modules/Setup`)
|
|
and ``python setup.py build``.
|
|
|
|
Main Makefile targets
|
|
---------------------
|
|
|
|
* ``make``: Build Python with the standard library.
|
|
* ``make platform:``: build the ``python`` program, but don't build the
|
|
standard library extension modules.
|
|
* ``make profile-opt``: build Python using Profile Guided Optimization (PGO).
|
|
You can use the configure :option:`--enable-optimizations` option to make
|
|
this the default target of the ``make`` command (``make all`` or just
|
|
``make``).
|
|
* ``make buildbottest``: Build Python and run the Python test suite, the same
|
|
way than buildbots test Python. Set ``TESTTIMEOUT`` variable (in seconds)
|
|
to change the test timeout (1200 by default: 20 minutes).
|
|
* ``make install``: Build and install Python.
|
|
* ``make regen-all``: Regenerate (almost) all generated files;
|
|
``make regen-stdlib-module-names`` and ``autoconf`` must be run separately
|
|
for the remaining generated files.
|
|
* ``make clean``: Remove built files.
|
|
* ``make distclean``: Same than ``make clean``, but remove also files created
|
|
by the configure script.
|
|
|
|
C extensions
|
|
------------
|
|
|
|
Some C extensions are built as built-in modules, like the ``sys`` module.
|
|
They are built with the ``Py_BUILD_CORE_BUILTIN`` macro defined.
|
|
Built-in modules have no ``__file__`` attribute::
|
|
|
|
>>> import sys
|
|
>>> sys
|
|
<module 'sys' (built-in)>
|
|
>>> sys.__file__
|
|
Traceback (most recent call last):
|
|
File "<stdin>", line 1, in <module>
|
|
AttributeError: module 'sys' has no attribute '__file__'
|
|
|
|
Other C extensions are built as dynamic libraries, like the ``_asyncio`` module.
|
|
They are built with the ``Py_BUILD_CORE_MODULE`` macro defined.
|
|
Example on Linux x86-64::
|
|
|
|
>>> import _asyncio
|
|
>>> _asyncio
|
|
<module '_asyncio' from '/usr/lib64/python3.9/lib-dynload/_asyncio.cpython-39-x86_64-linux-gnu.so'>
|
|
>>> _asyncio.__file__
|
|
'/usr/lib64/python3.9/lib-dynload/_asyncio.cpython-39-x86_64-linux-gnu.so'
|
|
|
|
:file:`Modules/Setup` is used to generate Makefile targets to build C extensions.
|
|
At the beginning of the files, C extensions are built as built-in modules.
|
|
Extensions defined after the ``*shared*`` marker are built as dynamic libraries.
|
|
|
|
The :file:`setup.py` script only builds C extensions as shared libraries using
|
|
the :mod:`distutils` module.
|
|
|
|
The :c:macro:`PyAPI_FUNC()`, :c:macro:`PyAPI_API()` and
|
|
:c:macro:`PyMODINIT_FUNC()` macros of :file:`Include/pyport.h` are defined
|
|
differently depending if the ``Py_BUILD_CORE_MODULE`` macro is defined:
|
|
|
|
* Use ``Py_EXPORTED_SYMBOL`` if the ``Py_BUILD_CORE_MODULE`` is defined
|
|
* Use ``Py_IMPORTED_SYMBOL`` otherwise.
|
|
|
|
If the ``Py_BUILD_CORE_BUILTIN`` macro is used by mistake on a C extension
|
|
built as a shared library, its ``PyInit_xxx()`` function is not exported,
|
|
causing an :exc:`ImportError` on import.
|
|
|
|
|
|
Compiler and linker flags
|
|
=========================
|
|
|
|
Options set by the ``./configure`` script and environment variables and used by
|
|
``Makefile``.
|
|
|
|
Preprocessor flags
|
|
------------------
|
|
|
|
.. envvar:: CONFIGURE_CPPFLAGS
|
|
|
|
Value of :envvar:`CPPFLAGS` variable passed to the ``./configure`` script.
|
|
|
|
.. versionadded:: 3.6
|
|
|
|
.. envvar:: CPPFLAGS
|
|
|
|
(Objective) C/C++ preprocessor flags, e.g. ``-I<include dir>`` if you have
|
|
headers in a nonstandard directory ``<include dir>``.
|
|
|
|
Both :envvar:`CPPFLAGS` and :envvar:`LDFLAGS` need to contain the shell's
|
|
value for setup.py to be able to build extension modules using the
|
|
directories specified in the environment variables.
|
|
|
|
.. envvar:: BASECPPFLAGS
|
|
|
|
.. versionadded:: 3.4
|
|
|
|
.. envvar:: PY_CPPFLAGS
|
|
|
|
Extra preprocessor flags added for building the interpreter object files.
|
|
|
|
Default: ``$(BASECPPFLAGS) -I. -I$(srcdir)/Include $(CONFIGURE_CPPFLAGS) $(CPPFLAGS)``.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
Compiler flags
|
|
--------------
|
|
|
|
.. envvar:: CC
|
|
|
|
C compiler command.
|
|
|
|
Example: ``gcc -pthread``.
|
|
|
|
.. envvar:: CXX
|
|
|
|
C++ compiler command.
|
|
|
|
Example: ``g++ -pthread``.
|
|
|
|
.. envvar:: CFLAGS
|
|
|
|
C compiler flags.
|
|
|
|
.. envvar:: CFLAGS_NODIST
|
|
|
|
:envvar:`CFLAGS_NODIST` is used for building the interpreter and stdlib C
|
|
extensions. Use it when a compiler flag should *not* be part of the
|
|
distutils :envvar:`CFLAGS` once Python is installed (:issue:`21121`).
|
|
|
|
In particular, :envvar:`CFLAGS` should not contain:
|
|
|
|
* the compiler flag ``-I`` (for setting the search path for include files).
|
|
The ``-I`` flags are processed from left to right, and any flags in
|
|
:envvar:`CFLAGS` would take precedence over user- and package-supplied ``-I``
|
|
flags.
|
|
|
|
* hardening flags such as ``-Werror`` because distributions cannot control
|
|
whether packages installed by users conform to such heightened
|
|
standards.
|
|
|
|
.. versionadded:: 3.5
|
|
|
|
.. envvar:: COMPILEALL_OPTS
|
|
|
|
Options passed to the :mod:`compileall` command line when building PYC files
|
|
in ``make install``. Default: ``-j0``.
|
|
|
|
.. versionadded:: 3.12
|
|
|
|
.. envvar:: EXTRA_CFLAGS
|
|
|
|
Extra C compiler flags.
|
|
|
|
.. envvar:: CONFIGURE_CFLAGS
|
|
|
|
Value of :envvar:`CFLAGS` variable passed to the ``./configure``
|
|
script.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
.. envvar:: CONFIGURE_CFLAGS_NODIST
|
|
|
|
Value of :envvar:`CFLAGS_NODIST` variable passed to the ``./configure``
|
|
script.
|
|
|
|
.. versionadded:: 3.5
|
|
|
|
.. envvar:: BASECFLAGS
|
|
|
|
Base compiler flags.
|
|
|
|
.. envvar:: OPT
|
|
|
|
Optimization flags.
|
|
|
|
.. envvar:: CFLAGS_ALIASING
|
|
|
|
Strict or non-strict aliasing flags used to compile ``Python/dtoa.c``.
|
|
|
|
.. versionadded:: 3.7
|
|
|
|
.. envvar:: CCSHARED
|
|
|
|
Compiler flags used to build a shared library.
|
|
|
|
For example, ``-fPIC`` is used on Linux and on BSD.
|
|
|
|
.. envvar:: CFLAGSFORSHARED
|
|
|
|
Extra C flags added for building the interpreter object files.
|
|
|
|
Default: ``$(CCSHARED)`` when :option:`--enable-shared` is used, or an empty
|
|
string otherwise.
|
|
|
|
.. envvar:: PY_CFLAGS
|
|
|
|
Default: ``$(BASECFLAGS) $(OPT) $(CONFIGURE_CFLAGS) $(CFLAGS) $(EXTRA_CFLAGS)``.
|
|
|
|
.. envvar:: PY_CFLAGS_NODIST
|
|
|
|
Default: ``$(CONFIGURE_CFLAGS_NODIST) $(CFLAGS_NODIST) -I$(srcdir)/Include/internal``.
|
|
|
|
.. versionadded:: 3.5
|
|
|
|
.. envvar:: PY_STDMODULE_CFLAGS
|
|
|
|
C flags used for building the interpreter object files.
|
|
|
|
Default: ``$(PY_CFLAGS) $(PY_CFLAGS_NODIST) $(PY_CPPFLAGS) $(CFLAGSFORSHARED)``.
|
|
|
|
.. versionadded:: 3.7
|
|
|
|
.. envvar:: PY_CORE_CFLAGS
|
|
|
|
Default: ``$(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE``.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
.. envvar:: PY_BUILTIN_MODULE_CFLAGS
|
|
|
|
Compiler flags to build a standard library extension module as a built-in
|
|
module, like the :mod:`posix` module.
|
|
|
|
Default: ``$(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE_BUILTIN``.
|
|
|
|
.. versionadded:: 3.8
|
|
|
|
.. envvar:: PURIFY
|
|
|
|
Purify command. Purify is a memory debugger program.
|
|
|
|
Default: empty string (not used).
|
|
|
|
|
|
Linker flags
|
|
------------
|
|
|
|
.. envvar:: LINKCC
|
|
|
|
Linker command used to build programs like ``python`` and ``_testembed``.
|
|
|
|
Default: ``$(PURIFY) $(CC)``.
|
|
|
|
.. envvar:: CONFIGURE_LDFLAGS
|
|
|
|
Value of :envvar:`LDFLAGS` variable passed to the ``./configure`` script.
|
|
|
|
Avoid assigning :envvar:`CFLAGS`, :envvar:`LDFLAGS`, etc. so users can use
|
|
them on the command line to append to these values without stomping the
|
|
pre-set values.
|
|
|
|
.. versionadded:: 3.2
|
|
|
|
.. envvar:: LDFLAGS_NODIST
|
|
|
|
:envvar:`LDFLAGS_NODIST` is used in the same manner as
|
|
:envvar:`CFLAGS_NODIST`. Use it when a linker flag should *not* be part of
|
|
the distutils :envvar:`LDFLAGS` once Python is installed (:issue:`35257`).
|
|
|
|
In particular, :envvar:`LDFLAGS` should not contain:
|
|
|
|
* the compiler flag ``-L`` (for setting the search path for libraries).
|
|
The ``-L`` flags are processed from left to right, and any flags in
|
|
:envvar:`LDFLAGS` would take precedence over user- and package-supplied ``-L``
|
|
flags.
|
|
|
|
.. envvar:: CONFIGURE_LDFLAGS_NODIST
|
|
|
|
Value of :envvar:`LDFLAGS_NODIST` variable passed to the ``./configure``
|
|
script.
|
|
|
|
.. versionadded:: 3.8
|
|
|
|
.. envvar:: LDFLAGS
|
|
|
|
Linker flags, e.g. ``-L<lib dir>`` if you have libraries in a nonstandard
|
|
directory ``<lib dir>``.
|
|
|
|
Both :envvar:`CPPFLAGS` and :envvar:`LDFLAGS` need to contain the shell's
|
|
value for setup.py to be able to build extension modules using the
|
|
directories specified in the environment variables.
|
|
|
|
.. envvar:: LIBS
|
|
|
|
Linker flags to pass libraries to the linker when linking the Python
|
|
executable.
|
|
|
|
Example: ``-lrt``.
|
|
|
|
.. envvar:: LDSHARED
|
|
|
|
Command to build a shared library.
|
|
|
|
Default: ``@LDSHARED@ $(PY_LDFLAGS)``.
|
|
|
|
.. envvar:: BLDSHARED
|
|
|
|
Command to build ``libpython`` shared library.
|
|
|
|
Default: ``@BLDSHARED@ $(PY_CORE_LDFLAGS)``.
|
|
|
|
.. envvar:: PY_LDFLAGS
|
|
|
|
Default: ``$(CONFIGURE_LDFLAGS) $(LDFLAGS)``.
|
|
|
|
.. envvar:: PY_LDFLAGS_NODIST
|
|
|
|
Default: ``$(CONFIGURE_LDFLAGS_NODIST) $(LDFLAGS_NODIST)``.
|
|
|
|
.. versionadded:: 3.8
|
|
|
|
.. envvar:: PY_CORE_LDFLAGS
|
|
|
|
Linker flags used for building the interpreter object files.
|
|
|
|
.. versionadded:: 3.8
|