3. Configurer Python

3.1. Build Requirements

Features and minimum versions required to build CPython:

• A C11 compiler. Optional C11 features are not required.

• On Windows, Microsoft Visual Studio 2017 or later is required.

• Support for IEEE 754 floating-point numbers and floating-point Not-a-Number (NaN).

• Support for threads.

• OpenSSL 1.1.1 is the minimum version and OpenSSL 3.0.9 is the recommended minimum version for the ssl and hashlib extension modules.

• SQLite 3.15.2 for the sqlite3 extension module.

• Tcl/Tk 8.5.12 for the tkinter module.

• Autoconf 2.71 and aclocal 1.16.5 are required to regenerate the configure script.

Modifié dans la version 3.1: Tcl/Tk version 8.3.1 is now required.

Modifié dans la version 3.5: On Windows, Visual Studio 2015 or later is now required. Tcl/Tk version 8.4 is now required.

Modifié dans la version 3.6: Selected C99 features are now required, like <stdint.h> and static inline functions.

Modifié dans la version 3.7: Thread support and OpenSSL 1.0.2 are now required.

Modifié dans la version 3.10: OpenSSL 1.1.1 is now required. Require SQLite 3.7.15.

Modifié dans la version 3.11: C11 compiler, IEEE 754 and NaN support are now required. On Windows, Visual Studio 2017 or later is required. Tcl/Tk version 8.5.12 is now required for the tkinter module.

Modifié dans la version 3.13: Autoconf 2.71, aclocal 1.16.5 and SQLite 3.15.2 are now required.

See also PEP 7 "Style Guide for C Code" and PEP 11 "CPython platform support".

3.2. Generated files

To reduce build dependencies, Python source code contains multiple generated files. Commands to regenerate all generated files:

make regen-all
make regen-stdlib-module-names
make regen-limited-abi
make regen-configure

The Makefile.pre.in file documents generated files, their inputs, and tools used to regenerate them. Search for regen-* make targets.

3.2.1. configure script

The make regen-configure command regenerates the aclocal.m4 file and the configure script using the Tools/build/regen-configure.sh shell script which uses an Ubuntu container to get the same tools versions and have a reproducible output.

The container is optional, the following command can be run locally:

autoreconf -ivf -Werror

The generated files can change depending on the exact autoconf-archive, aclocal and pkg-config versions.

3.3. Options de configuration

List all configure script options using:

./configure --help

Voir aussi le fichier Misc/SpecialBuilds.txt dans la distribution des sources Python.

3.3.1. Options générales

--enable-loadable-sqlite-extensions

Support loadable extensions in the _sqlite extension module (default is no) of the sqlite3 module.

Voir la méthode sqlite3.Connection.enable_load_extension() du module sqlite3.

Ajouté dans la version 3.6.

--disable-ipv6

Désactive la prise en charge d'IPv6 (activé par défaut si géré), voir le module socket.

--enable-big-digits=[15|30]

Définit la taille en bits des chiffres Python int : 15 ou 30 bits.

La valeur par défaut est 30 bits.

Définit PYLONG_BITS_IN_DIGIT à 15 ou 30.

Voir sys.int_info.bits_per_digit.

--with-suffix=SUFFIX

Définit à SUFFIX le suffixe de l'exécutable Python.

Le suffixe par défaut est .exe sur Windows et macOS (exécutable python.exe), .js pour Emscripten (node), .html pour Emscripten (navigateur), .wasm pour WASI, et une chaîne vide sur les autres plateformes (exécutable python).

Modifié dans la version 3.11: les suffixes par défaut pour la plateforme WASM sont maintenant .js, .html et .wasm.

--with-tzpath=<list of absolute paths separated by pathsep>

Select the default time zone search path for zoneinfo.TZPATH. See the Compile-time configuration of the zoneinfo module.

Par défaut : /usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo.

Voir le séparateur de chemins os.pathsep.

Ajouté dans la version 3.9.

--without-decimal-contextvar

Compile le module d'extension _decimal en utilisant un contexte local au fil d'exécution plutôt qu'un contexte local de coroutine (défaut). Voir le module decimal.

See decimal.HAVE_CONTEXTVAR and the contextvars module.

Ajouté dans la version 3.9.

--with-dbmliborder=<list of backend names>

Change l'ordre de détection des implémentations de base de données pour le module dbm.

Une valeur valide est une chaîne de noms d'implémentations séparés par des deux-points (:) :

• ndbm ;

• gdbm ;

• bdb.

--without-c-locale-coercion

Désactive le forçage des paramètres régionaux C pour un paramètre régional basé sur UTF-8 (activé par défaut).

Ne pas définir la macro PY_COERCE_C_LOCALE.

Voir PYTHONCOERCECLOCALE et la PEP 538.

--without-freelists

Disable all freelists except the empty tuple singleton.

Ajouté dans la version 3.11.

--with-platlibdir=DIRNAME

Nom du dossier de bibliothèques Python (par défaut : lib).

Fedora et SuSE utilisent lib64 sur les systèmes 64-bit.

Voir sys.platlibdir.

Ajouté dans la version 3.9.

--with-wheel-pkg-dir=PATH

Dossier de paquets wheel utilisé par le module ensurepip (par défaut : aucun).

Some Linux distribution packaging policies recommend against bundling dependencies. For example, Fedora installs wheel packages in the /usr/share/python-wheels/ directory and don't install the ensurepip._bundled package.

Ajouté dans la version 3.10.

--with-pkg-config=[check|yes|no]

Est-ce que configure doit utiliser pkg-config pour détecter les dépendances de construction.

• check (par défaut) : pkg-config est optionnel

• yes : pkg-config est obligatoire

• no : configure n'utilise pas pkg-config même s'il est présent

Ajouté dans la version 3.11.

--enable-pystats

Turn on internal Python performance statistics gathering.

By default, statistics gathering is off. Use python3 -X pystats command or set PYTHONSTATS=1 environment variable to turn on statistics gathering at Python startup.

At Python exit, dump statistics if statistics gathering was on and not cleared.

Effects:

• Add -X pystats command line option.

• Add PYTHONSTATS environment variable.

• Define the Py_STATS macro.

• Add functions to the sys module:

  • sys._stats_on(): Turns on statistics gathering.

  • sys._stats_off(): Turns off statistics gathering.

  • sys._stats_clear(): Clears the statistics.

  • sys._stats_dump(): Dump statistics to file, and clears the statistics.

The statistics will be dumped to a arbitrary (probably unique) file in /tmp/py_stats/ (Unix) or C:\temp\py_stats\ (Windows). If that directory does not exist, results will be printed on stderr.

Utilisez Tools/scripts/summarize_stats.py pour lire les statistiques.

Statistics:

• Opcode:

  • Specialization: success, failure, hit, deferred, miss, deopt, failures;

  • Execution count;

  • Pair count.

• Call:

  • Inlined Python calls;

  • PyEval calls;

  • Frames pushed;

  • Frame object created;

  • Eval calls: vector, generator, legacy, function VECTORCALL, build class, slot, function "ex", API, method.

• Object:

  • incref and decref;

  • interpreter incref and decref;

  • allocations: all, 512 bytes, 4 kiB, big;

  • free;

  • to/from free lists;

  • dictionary materialized/dematerialized;

  • type cache;

  • optimization attempts;

  • optimization traces created/executed;

  • uops executed.

• Garbage collector:

  • Garbage collections;

  • Objects visited;

  • Objects collected.

Ajouté dans la version 3.11.

--disable-gil

Enables experimental support for running Python without the global interpreter lock (GIL): free threading build.

Defines the Py_GIL_DISABLED macro and adds "t" to sys.abiflags.

See Free-threaded CPython for more detail.

Ajouté dans la version 3.13.

--enable-experimental-jit=[no|yes|yes-off|interpreter]

Indicate how to integrate the JIT compiler.

• no - build the interpreter without the JIT.

• yes - build the interpreter with the JIT.

• yes-off - build the interpreter with the JIT but disable it by default.

• interpreter - build the interpreter without the JIT, but with the tier 2 enabled interpreter.

By convention, --enable-experimental-jit is a shorthand for --enable-experimental-jit=yes.

Ajouté dans la version 3.13.

PKG_CONFIG

Path to pkg-config utility.

PKG_CONFIG_LIBDIR

PKG_CONFIG_PATH

pkg-config options.

3.3.2. C compiler options

CC

C compiler command.

CFLAGS

C compiler flags.

CPP

C preprocessor command.

CPPFLAGS

C preprocessor flags, e.g. -Iinclude_dir.

3.3.3. Linker options

LDFLAGS

Linker flags, e.g. -Llibrary_directory.

LIBS

Libraries to pass to the linker, e.g. -llibrary.

MACHDEP

Name for machine-dependent library files.

3.3.4. Options for third-party dependencies

Ajouté dans la version 3.11.

BZIP2_CFLAGS

BZIP2_LIBS

C compiler and linker flags to link Python to libbz2, used by bz2 module, overriding pkg-config.

CURSES_CFLAGS

CURSES_LIBS

C compiler and linker flags for libncurses or libncursesw, used by curses module, overriding pkg-config.

GDBM_CFLAGS

GDBM_LIBS

C compiler and linker flags for gdbm.

LIBB2_CFLAGS

LIBB2_LIBS

C compiler and linker flags for libb2 (BLAKE2), used by hashlib module, overriding pkg-config.

LIBEDIT_CFLAGS

LIBEDIT_LIBS

C compiler and linker flags for libedit, used by readline module, overriding pkg-config.

LIBFFI_CFLAGS

LIBFFI_LIBS

C compiler and linker flags for libffi, used by ctypes module, overriding pkg-config.

LIBMPDEC_CFLAGS

LIBMPDEC_LIBS

C compiler and linker flags for libmpdec, used by decimal module, overriding pkg-config.

Note

These environment variables have no effect unless --with-system-libmpdec is specified.

LIBLZMA_CFLAGS

LIBLZMA_LIBS

C compiler and linker flags for liblzma, used by lzma module, overriding pkg-config.

LIBREADLINE_CFLAGS

LIBREADLINE_LIBS

C compiler and linker flags for libreadline, used by readline module, overriding pkg-config.

LIBSQLITE3_CFLAGS

LIBSQLITE3_LIBS

C compiler and linker flags for libsqlite3, used by sqlite3 module, overriding pkg-config.

LIBUUID_CFLAGS

LIBUUID_LIBS

C compiler and linker flags for libuuid, used by uuid module, overriding pkg-config.

PANEL_CFLAGS

PANEL_LIBS

C compiler and linker flags for PANEL, overriding pkg-config.

C compiler and linker flags for libpanel or libpanelw, used by curses.panel module, overriding pkg-config.

TCLTK_CFLAGS

TCLTK_LIBS

C compiler and linker flags for TCLTK, overriding pkg-config.

ZLIB_CFLAGS

ZLIB_LIBS

C compiler and linker flags for libzlib, used by gzip module, overriding pkg-config.

3.3.5. Options de WebAssembly

--with-emscripten-target=[browser|node]

Définit la version de construction pour wasm32-emscripten.

• browser (par défaut) : précharge une version minimale de la stdlib, par défaut MEMFS.

• node: NODERAWFS et la gestion des pthread.

Ajouté dans la version 3.11.

--enable-wasm-dynamic-linking

Active la gestion d'édition de liens dynamique pour WASM

L'édition de liens dynamique autorise dlopen. La taille du fichier exécutable augmente en raison de l'élimination moindre du code mort et des fonctionnalités supplémentaires.

Ajouté dans la version 3.11.

--enable-wasm-pthreads

Active la gestion des pthreads pour WASM.

Ajouté dans la version 3.11.

3.3.6. Options d'installation

--prefix=PREFIX

Install architecture-independent files in PREFIX. On Unix, it defaults to /usr/local.

This value can be retrieved at runtime using sys.prefix.

As an example, one can use --prefix="$HOME/.local/" to install a Python in its home directory.

--exec-prefix=EPREFIX

Install architecture-dependent files in EPREFIX, defaults to --prefix.

This value can be retrieved at runtime using sys.exec_prefix.

--disable-test-modules

Don't build nor install test modules, like the test package or the _testcapi extension module (built and installed by default).

Ajouté dans la version 3.10.

--with-ensurepip=[upgrade|install|no]

Sélectionne la commande ensurepip exécutée à l'installation de Python :

• upgrade (défaut) : exécute la commande python -m ensurepip --altinstall --upgrade ;

• install : exécute la commande python -m ensurepip --altinstall ;

• no : n'exécute pas ensurepip.

Ajouté dans la version 3.6.

3.3.7. Options de performance

Configuring Python using --enable-optimizations --with-lto (PGO + LTO) is recommended for best performance. The experimental --enable-bolt flag can also be used to improve performance.

--enable-optimizations

Active l'optimisation guidée par profilage (Profile Guided Optimization, PGO) en utilisant PROFILE_TASK (désactivé par défaut).

L'utilisation de PGO avec le compilateur C Clang nécessite llvm-profdata. Sur macOS, GCC est juste un alias vers Clang et partage donc cette contrainte.

Désactive également l'interposition sémantique dans libpython si GCC est utilisé avec --enable-shared : ajoute l'option -fno-semantic-interposition à la compilation et à l'édition des liens.

Note

During the build, you may encounter compiler warnings about profile data not being available for some source files. These warnings are harmless, as only a subset of the code is exercised during profile data acquisition. To disable these warnings on Clang, manually suppress them by adding -Wno-profile-instr-unprofiled to CFLAGS.

Ajouté dans la version 3.6.

Modifié dans la version 3.10: Utilisation de -fno-semantic-interposition avec GCC.

PROFILE_TASK

Variable d'environnement utilisée dans le Makefile : arguments Python utilisés pour la tâche de préparation de la PGO.

Par défaut : -m test --pgo --timeout=$(TESTTIMEOUT).

Ajouté dans la version 3.8.

Modifié dans la version 3.13: Task failure is no longer ignored silently.

--with-lto=[full|thin|no|yes]

Active l'optimisation à l'édition des liens (Link Time Optimization, LTO) à la compilation (désactivé par défaut).

Le compilateur C Clang nécessite llvm-ar pour la LTO (ar sur macOS), ainsi qu'un éditeur de liens implémentant la LTO (ld.gold ou lld).

Ajouté dans la version 3.6.

Ajouté dans la version 3.11: Pour avoir la fonctionnalité ThinLTO, utilisez --with-lto=thin avec Clang.

Modifié dans la version 3.12: Use ThinLTO as the default optimization policy on Clang if the compiler accepts the flag.

--enable-bolt

Enable usage of the BOLT post-link binary optimizer (disabled by default).

BOLT is part of the LLVM project but is not always included in their binary distributions. This flag requires that llvm-bolt and merge-fdata are available.

BOLT is still a fairly new project so this flag should be considered experimental for now. Because this tool operates on machine code its success is dependent on a combination of the build environment + the other optimization configure args + the CPU architecture, and not all combinations are supported. BOLT versions before LLVM 16 are known to crash BOLT under some scenarios. Use of LLVM 16 or newer for BOLT optimization is strongly encouraged.

The BOLT_INSTRUMENT_FLAGS and BOLT_APPLY_FLAGS configure variables can be defined to override the default set of arguments for llvm-bolt to instrument and apply BOLT data to binaries, respectively.

Ajouté dans la version 3.12.

BOLT_APPLY_FLAGS

Arguments to llvm-bolt when creating a BOLT optimized binary.

Ajouté dans la version 3.12.

BOLT_INSTRUMENT_FLAGS

Arguments to llvm-bolt when instrumenting binaries.

Ajouté dans la version 3.12.

--with-computed-gotos

Autorise les gotos calculés dans les boucles (activé par défaut pour les compilateurs qui le gèrent).

--without-mimalloc

Disable the fast mimalloc allocator (enabled by default).

Voir aussi la variable d'environnement PYTHONMALLOC.

--without-pymalloc

Désactive l'allocateur spécialisé de mémoire de Python pymalloc (activé par défaut).

Voir aussi la variable d'environnement PYTHONMALLOC.

--without-doc-strings

Désactive les chaînes de documentation statiques pour réduire l'empreinte mémoire (activé par défaut). Les chaînes définies dans Python ne sont pas affectées.

Ne définit pas la macro WITH_DOC_STRINGS.

Voir la macro PyDoc_STRVAR().

--enable-profiling

Active le profilage du code C avec gprof (désactivé par défaut).

--with-strict-overflow

Add -fstrict-overflow to the C compiler flags (by default we add -fno-strict-overflow instead).

3.3.8. Compilation de Python en mode débogage

Une compilation de Python en mode débogage se fait avec l'option de configuration --with-pydebug.

Effets du mode débogage :

• Affichage de tous les avertissements par défaut : le filtre par défaut des avertissements est vide dans le module warnings.

• Ajout de d à sys.abiflags.

• Add sys.gettotalrefcount() function.

• Ajout de l'option de ligne de commande -X showrefcount.

• Add -d command line option and PYTHONDEBUG environment variable to debug the parser.

• Prise en charge de la variable __ltrace__ : si la variable est définie, active le traçage de bas niveau dans la boucle d'évaluation du code intermédiaire.

• Installation des debug hooks on memory allocators pour détecter les débordements de mémoire tampon et autres erreurs de mémoire.

• Définition des macros Py_DEBUG et Py_REF_DEBUG.

• Ajout de vérifications à l'exécution : codes entourés de #ifdef Py_DEBUG et #endif. Active les assertions assert(...) et _PyObject_ASSERT(...) : ne définit pas la macro NDEBUG (voir aussi l'option de configuration --with-assertions). Les principales vérifications à l'exécution :

  • Ajout des contrôles d'intégrité sur les arguments de fonction.

  • Les objets unicode et int sont créés avec un motif particulier à l'initialisation de leur mémoire afin de détecter l'usage d'objets non initialisés.

  • S'assurer que les fonctions qui peuvent effacer ou remplacer l'exception courante ne sont pas appelées avec une exception levée.

  • S'assurer que les fonctions qui désallouent ne changent pas l'exception en cours.

  • Le ramasse-miettes (la fonction gc.collect()) effectue quelques tests basiques relatifs à la cohérence des objets.

  • The Py_SAFE_DOWNCAST() macro checks for integer underflow and overflow when downcasting from wide types to narrow types.

Voir aussi le mode de développement Python et l'option de configuration --with-trace-refs.

Modifié dans la version 3.8: Release builds and debug builds are now ABI compatible: defining the Py_DEBUG macro no longer implies the Py_TRACE_REFS macro (see the --with-trace-refs option).

3.3.9. Debug options

--with-pydebug

Build Python in debug mode: define the Py_DEBUG macro (disabled by default).

--with-trace-refs

Enable tracing references for debugging purpose (disabled by default).

Effects:

• Define the Py_TRACE_REFS macro.

• Add sys.getobjects() function.

• Add PYTHONDUMPREFS environment variable.

The PYTHONDUMPREFS environment variable can be used to dump objects and reference counts still alive at Python exit.

Statically allocated objects are not traced.

Ajouté dans la version 3.8.

Modifié dans la version 3.13: This build is now ABI compatible with release build and debug build.

--with-assertions

Build with C assertions enabled (default is no): assert(...); and _PyObject_ASSERT(...);.

If set, the NDEBUG macro is not defined in the OPT compiler variable.

See also the --with-pydebug option (debug build) which also enables assertions.

Ajouté dans la version 3.6.

--with-valgrind

Enable Valgrind support (default is no).

--with-dtrace

Enable DTrace support (default is no).

See Instrumenting CPython with DTrace and SystemTap.

Ajouté dans la version 3.6.

--with-address-sanitizer

Enable AddressSanitizer memory error detector, asan (default is no).

Ajouté dans la version 3.6.

--with-memory-sanitizer

Enable MemorySanitizer allocation error detector, msan (default is no).

Ajouté dans la version 3.6.

--with-undefined-behavior-sanitizer

Enable UndefinedBehaviorSanitizer undefined behaviour detector, ubsan (default is no).

Ajouté dans la version 3.6.

--with-thread-sanitizer

Enable ThreadSanitizer data race detector, tsan (default is no).

Ajouté dans la version 3.13.

3.3.10. Linker options

--enable-shared

Enable building a shared Python library: libpython (default is no).

--without-static-libpython

Do not build libpythonMAJOR.MINOR.a and do not install python.o (built and enabled by default).

Ajouté dans la version 3.10.

3.3.11. Libraries options

--with-libs='lib1 ...'

Link against additional libraries (default is no).

--with-system-expat

Build the pyexpat module using an installed expat library (default is no).

--with-system-libmpdec

Build the _decimal extension module using an installed mpdecimal library, see the decimal module (default is yes).

Ajouté dans la version 3.3.

Modifié dans la version 3.13: Default to using the installed mpdecimal library.

Deprecated since version 3.13, will be removed in version 3.15: A copy of the mpdecimal library sources will no longer be distributed with Python 3.15.

Voir aussi

LIBMPDEC_CFLAGS and LIBMPDEC_LIBS.

--with-readline=readline|editline

Designate a backend library for the readline module.

• readline: Use readline as the backend.

• editline: Use editline as the backend.

Ajouté dans la version 3.10.

--without-readline

Don't build the readline module (built by default).

Don't define the HAVE_LIBREADLINE macro.

Ajouté dans la version 3.10.

--with-libm=STRING

Override libm math library to STRING (default is system-dependent).

--with-libc=STRING

Override libc C library to STRING (default is system-dependent).

--with-openssl=DIR

Root of the OpenSSL directory.

Ajouté dans la version 3.7.

--with-openssl-rpath=[no|auto|DIR]

Set runtime library directory (rpath) for OpenSSL libraries:

• no (default): don't set rpath;

• auto: auto-detect rpath from --with-openssl and pkg-config;

• DIR: set an explicit rpath.

Ajouté dans la version 3.10.

3.3.12. Security Options

--with-hash-algorithm=[fnv|siphash13|siphash24]

Select hash algorithm for use in Python/pyhash.c:

• siphash13 (default);

• siphash24;

• fnv.

Ajouté dans la version 3.4.

Ajouté dans la version 3.11: siphash13 is added and it is the new default.

--with-builtin-hashlib-hashes=md5,sha1,sha256,sha512,sha3,blake2

Built-in hash modules:

• md5;

• sha1;

• sha256;

• sha512;

• sha3 (with shake);

• blake2.

Ajouté dans la version 3.9.

--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 ssl module.

Ajouté dans la version 3.7.

Modifié dans la version 3.10: The settings python and STRING also set TLS 1.2 as minimum protocol version.

3.3.13. macOS Options

See Mac/README.rst.

--enable-universalsdk

--enable-universalsdk=SDKDIR

Create a universal binary build. SDKDIR specifies which macOS SDK should be used to perform the build (default is no).

--enable-framework

--enable-framework=INSTALLDIR

Create a Python.framework rather than a traditional Unix install. Optional INSTALLDIR specifies the installation path (default is no).

--with-universal-archs=ARCH

Specify the kind of universal binary that should be created. This option is only valid when --enable-universalsdk is set.

Options:

• universal2;

• 32-bit;

• 64-bit;

• 3-way;

• intel;

• intel-32;

• intel-64;

• all.

--with-framework-name=FRAMEWORK

Specify the name for the python framework on macOS only valid when --enable-framework is set (default: Python).

--with-app-store-compliance

--with-app-store-compliance=PATCH-FILE

The Python standard library contains strings that are known to trigger automated inspection tool errors when submitted for distribution by the macOS and iOS App Stores. If enabled, this option will apply the list of patches that are known to correct app store compliance. A custom patch file can also be specified. This option is disabled by default.

Ajouté dans la version 3.13.

3.3.14. iOS Options

See iOS/README.rst.

--enable-framework=INSTALLDIR

Create a Python.framework. Unlike macOS, the INSTALLDIR argument specifying the installation path is mandatory.

--with-framework-name=FRAMEWORK

Specify the name for the framework (default: Python).

3.3.15. 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.

--build=BUILD

configure for building on BUILD, usually guessed by config.guess.

--host=HOST

cross-compile to build programs to run on HOST (target platform)

--with-build-python=path/to/python

path to build python binary for cross compiling

Ajouté dans la version 3.11.

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

HOSTRUNNER

Program to run CPython for the host platform for cross-compilation.

Ajouté dans la version 3.11.

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

3.4. Python Build System

3.4.1. Main files of the build system

• configure.ac => configure;

• Makefile.pre.in => Makefile (created by configure);

• pyconfig.h (created by configure);

• Modules/Setup: C extensions built by the Makefile using Module/makesetup shell script;

3.4.2. 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 Modules/Setup).

3.4.3. Main Makefile targets

3.4.3.1. make

For the most part, when rebuilding after editing some code or refreshing your checkout from upstream, all you need to do is execute make, which (per Make's semantics) builds the default target, the first one defined in the Makefile. By tradition (including in the CPython project) this is usually the all target. The configure script expands an autoconf variable, @DEF_MAKE_ALL_RULE@ to describe precisely which targets make all will build. The three choices are:

• profile-opt (configured with --enable-optimizations)

• build_wasm (configured with --with-emscripten-target)

• build_all (configured without explicitly using either of the others)

Depending on the most recent source file changes, Make will rebuild any targets (object files and executables) deemed out-of-date, including running configure again if necessary. Source/target dependencies are many and maintained manually however, so Make sometimes doesn't have all the information necessary to correctly detect all targets which need to be rebuilt. Depending on which targets aren't rebuilt, you might experience a number of problems. If you have build or test problems which you can't otherwise explain, make clean && make should work around most dependency problems, at the expense of longer build times.

3.4.3.2. make platform

Build the python program, but don't build the standard library extension modules. This generates a file named platform which contains a single line describing the details of the build platform, e.g., macosx-14.3-arm64-3.12 or linux-x86_64-3.13.

3.4.3.3. make profile-opt

Build Python using profile-guided optimization (PGO). You can use the configure --enable-optimizations option to make this the default target of the make command (make all or just make).

3.4.3.4. make clean

Remove built files.

3.4.3.5. make distclean

In addition to the work done by make clean, remove files created by the configure script. configure will have to be run before building again. [1]

3.4.3.6. make install

Build the all target and install Python.

3.4.3.7. make test

Build the all target and run the Python test suite with the --fast-ci option. Variables:

• TESTOPTS: additional regrtest command-line options.

• TESTPYTHONOPTS: additional Python command-line options.

• TESTTIMEOUT: timeout in seconds (default: 10 minutes).

3.4.3.8. make buildbottest

This is similar to make test, but uses the --slow-ci option and default timeout of 20 minutes, instead of --fast-ci option.

3.4.3.9. make regen-all

Regenerate (almost) all generated files. These include (but are not limited to) bytecode cases, and parser generator file. make regen-stdlib-module-names and autoconf must be run separately for the remaining generated files.

3.4.4. 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'

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 PyAPI_FUNC(), PyAPI_DATA() and PyMODINIT_FUNC macros of Include/exports.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 ImportError on import.

3.5. Compiler and linker flags

Options set by the ./configure script and environment variables and used by Makefile.

3.5.1. Preprocessor flags

CONFIGURE_CPPFLAGS

Value of CPPFLAGS variable passed to the ./configure script.

Ajouté dans la version 3.6.

CPPFLAGS

(Objective) C/C++ preprocessor flags, e.g. -Iinclude_dir if you have headers in a nonstandard directory include_dir.

Both CPPFLAGS and LDFLAGS need to contain the shell's value to be able to build extension modules using the directories specified in the environment variables.

BASECPPFLAGS

Ajouté dans la version 3.4.

PY_CPPFLAGS

Extra preprocessor flags added for building the interpreter object files.

Default: $(BASECPPFLAGS) -I. -I$(srcdir)/Include $(CONFIGURE_CPPFLAGS) $(CPPFLAGS).

Ajouté dans la version 3.2.

3.5.2. Compiler flags

CC

C compiler command.

Example: gcc -pthread.

CXX

C++ compiler command.

Example: g++ -pthread.

CFLAGS

C compiler flags.

CFLAGS_NODIST

CFLAGS_NODIST is used for building the interpreter and stdlib C extensions. Use it when a compiler flag should not be part of CFLAGS once Python is installed (gh-65320).

In particular, 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 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.

Ajouté dans la version 3.5.

COMPILEALL_OPTS

Options passed to the compileall command line when building PYC files in make install. Default: -j0.

Ajouté dans la version 3.12.

EXTRA_CFLAGS

Extra C compiler flags.

CONFIGURE_CFLAGS

Value of CFLAGS variable passed to the ./configure script.

Ajouté dans la version 3.2.

CONFIGURE_CFLAGS_NODIST

Value of CFLAGS_NODIST variable passed to the ./configure script.

Ajouté dans la version 3.5.

BASECFLAGS

Base compiler flags.

OPT

Optimization flags.

CFLAGS_ALIASING

Strict or non-strict aliasing flags used to compile Python/dtoa.c.

Ajouté dans la version 3.7.

CCSHARED

Compiler flags used to build a shared library.

For example, -fPIC is used on Linux and on BSD.

CFLAGSFORSHARED

Extra C flags added for building the interpreter object files.

Default: $(CCSHARED) when --enable-shared is used, or an empty string otherwise.

PY_CFLAGS

Default: $(BASECFLAGS) $(OPT) $(CONFIGURE_CFLAGS) $(CFLAGS) $(EXTRA_CFLAGS).

PY_CFLAGS_NODIST

Default: $(CONFIGURE_CFLAGS_NODIST) $(CFLAGS_NODIST) -I$(srcdir)/Include/internal.

Ajouté dans la version 3.5.

PY_STDMODULE_CFLAGS

C flags used for building the interpreter object files.

Default: $(PY_CFLAGS) $(PY_CFLAGS_NODIST) $(PY_CPPFLAGS) $(CFLAGSFORSHARED).

Ajouté dans la version 3.7.

PY_CORE_CFLAGS

Default: $(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE.

Ajouté dans la version 3.2.

PY_BUILTIN_MODULE_CFLAGS

Compiler flags to build a standard library extension module as a built-in module, like the posix module.

Default: $(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE_BUILTIN.

Ajouté dans la version 3.8.

PURIFY

Purify command. Purify is a memory debugger program.

Default: empty string (not used).

3.5.3. Linker flags

LINKCC

Linker command used to build programs like python and _testembed.

Default: $(PURIFY) $(CC).

CONFIGURE_LDFLAGS

Value of LDFLAGS variable passed to the ./configure script.

Avoid assigning CFLAGS, LDFLAGS, etc. so users can use them on the command line to append to these values without stomping the pre-set values.

Ajouté dans la version 3.2.

LDFLAGS_NODIST

LDFLAGS_NODIST is used in the same manner as CFLAGS_NODIST. Use it when a linker flag should not be part of LDFLAGS once Python is installed (gh-65320).

In particular, 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 LDFLAGS would take precedence over user- and package-supplied -L flags.

CONFIGURE_LDFLAGS_NODIST

Value of LDFLAGS_NODIST variable passed to the ./configure script.

Ajouté dans la version 3.8.

LDFLAGS

Linker flags, e.g. -Llib_dir if you have libraries in a nonstandard directory lib_dir.

Both CPPFLAGS and LDFLAGS need to contain the shell's value to be able to build extension modules using the directories specified in the environment variables.

LIBS

Linker flags to pass libraries to the linker when linking the Python executable.

Example: -lrt.

LDSHARED

Command to build a shared library.

Default: @LDSHARED@ $(PY_LDFLAGS).

BLDSHARED

Command to build libpython shared library.

Default: @BLDSHARED@ $(PY_CORE_LDFLAGS).

PY_LDFLAGS

Default: $(CONFIGURE_LDFLAGS) $(LDFLAGS).

PY_LDFLAGS_NODIST

Default: $(CONFIGURE_LDFLAGS_NODIST) $(LDFLAGS_NODIST).

Ajouté dans la version 3.8.

PY_CORE_LDFLAGS

Linker flags used for building the interpreter object files.

Ajouté dans la version 3.8.

Notes

[1]

git clean -fdx is an even more extreme way to "clean" your checkout. It removes all files not known to Git. When bug hunting using git bisect, this is recommended between probes to guarantee a completely clean build. Use with care, as it will delete all files not checked into Git, including your new, uncommitted work.