# 3. Configurer Python

## 3.1. Build Requirements

Features required to build CPython:

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

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

- Support for threads.

- OpenSSL 1.1.1 or newer for the `ssl` and `hashlib` modules.

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

Modifié dans la version 3.5: On Windows, Visual Studio 2015 or later is 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.

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.

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

Il est possible d'obtenir toutes les options de `./configure` avec :

    ./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`.

  Added in 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`.

  Added in 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.

  Added in 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.

  Added in 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`.

  Added in 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.

  Added in 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

  Added in version 3.11.

--enable-pystats

  Active la collecte des statistiques internes.

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

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

  Added in version 3.11.

### 3.3.2. 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.

  Added in 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.

  Added in version 3.11.

--enable-wasm-pthreads

  Active la gestion des pthreads pour WASM.

  Added in version 3.11.

### 3.3.3. 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).

  Added in 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.

  Added in version 3.6.

### 3.3.4. 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`.

  Added in 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)`.

  Added in version 3.8.

--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`).

  Added in version 3.6.

  Added in 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.

  Added in version 3.12.

--with-computed-gotos

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

--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).

### 3.3.5. 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), which introduces the only ABI incompatibility.

### 3.3.6. 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.

  This build is not ABI compatible with release build (default build) or debug build (`Py_DEBUG` and `Py_REF_DEBUG` macros).

  Added in version 3.8.

--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.

  Added in 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.

  Added in version 3.6.

--with-address-sanitizer

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

  Added in version 3.6.

--with-memory-sanitizer

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

  Added in version 3.6.

--with-undefined-behavior-sanitizer

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

  Added in version 3.6.

### 3.3.7. 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).

  Added in version 3.10.

### 3.3.8. 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 `mpdec` library, see the `decimal` module (default is no).

  Added in version 3.3.

--with-readline=editline

  Use `editline` library for backend of the `readline` module.

  Define the `WITH_EDITLINE` macro.

  Added in version 3.10.

--without-readline

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

  Don't define the `HAVE_LIBREADLINE` macro.

  Added in 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.

  Added in 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.

  Added in version 3.10.

### 3.3.9. Security Options

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

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

  - `siphash13` (default);

  - `siphash24`;

  - `fnv`.

  Added in version 3.4.

  Added in 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`.

  Added in 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.

  Added in version 3.7.

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

### 3.3.10. 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`).

### 3.3.11. 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

  Added in 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

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

- `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 `--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.

### 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.

  Added in 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

  Added in version 3.4.

PY_CPPFLAGS

  Extra preprocessor flags added for building the interpreter object files.

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

  Added in 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.

  Added in version 3.5.

COMPILEALL_OPTS

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

  Added in version 3.12.

EXTRA_CFLAGS

  Extra C compiler flags.

CONFIGURE_CFLAGS

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

  Added in version 3.2.

CONFIGURE_CFLAGS_NODIST

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

  Added in version 3.5.

BASECFLAGS

  Base compiler flags.

OPT

  Optimization flags.

CFLAGS_ALIASING

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

  Added in 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`.

  Added in version 3.5.

PY_STDMODULE_CFLAGS

  C flags used for building the interpreter object files.

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

  Added in version 3.7.

PY_CORE_CFLAGS

  Default: `$(PY_STDMODULE_CFLAGS) -DPy_BUILD_CORE`.

  Added in 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`.

  Added in 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.

  Added in 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.

  Added in 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)`.

  Added in version 3.8.

PY_CORE_LDFLAGS

  Linker flags used for building the interpreter object files.

  Added in version 3.8.