3. Python を構成する

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 1.16.4 are required to regenerate the configure script.

バージョン 3.1 で変更: Tcl/Tk version 8.3.1 is now required.

バージョン 3.5 で変更: On Windows, Visual Studio 2015 or later is now required. Tcl/Tk version 8.4 is now required.

バージョン 3.6 で変更: Selected C99 features are now required, like <stdint.h> and static inline functions.

バージョン 3.7 で変更: Thread support and OpenSSL 1.0.2 are now required.

バージョン 3.10 で変更: OpenSSL 1.1.1 is now required. Require SQLite 3.7.15.

バージョン 3.11 で変更: 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.

バージョン 3.13 で変更: Autoconf 2.71, aclocal 1.16.4 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. 生成されるファイル

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. 構成スクリプト

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. Configureオプション

List all configure script options using:

./configure --help

Pythonのソース配布の中の Misc/SpecialBuilds.txt も参照してください。

3.3.1. 一般的なオプション


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

sqlite3 モジュールの sqlite3.Connection.enable_load_extension() メソッドを参照してください。

Added in version 3.6.


IPv6サポートを無効にします(サポートされている場合はデフォルトで有効)、 socket モジュールを参照してください。


Python int の桁の大きさをビット単位で定義します: 15ビットまたは30ビットです。


PYLONG_BITS_IN_DIGIT15 または 30 に定義します。

sys.int_info.bits_per_digit を参照してください。


Python の実行ファイルの接頭辞を SUFFIX に設定します。

デフォルトの接尾辞は、 Windows と macOS では .exe ( python.exe 実行ファイル)、 Emscripten node では .js 、 Emscripten browser では .html 、 WASI では .wasm 、その他のプラットフォームでは空文字列になります ( python 実行ファイル)。

バージョン 3.11 で変更: WASM プラットフォームのデフォルトの接頭辞は、 .js.html.wasm のうちの1つです。

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

デフォルトのタイムゾーン検索パスを zoneinfo.TZPATH に設定します。zoneinfo モジュールの Compile-time configuration を参照してください。

デフォルト: /usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo

os.pathsep パスセパレータを参照してください。

Added in version 3.9.


コルーチンローカルコンテキスト(デフォルト)ではなく、スレッドローカルコンテキストを使用して _decimal 拡張モジュールをビルドします。 decimal モジュールを参照してください。

decimal.HAVE_CONTEXTVAR および contextvars モジュールを参照してください。

Added in version 3.9.

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

dbm モジュールの DB バックエンドをチェックする順序をオーバーライドします。

有効な値は、バックエンド名をコロン( : )で区切った文字列です:

  • ndbm;

  • gdbm;

  • bdb


UTF-8 ベースのロケールへの C ロケールの強制を無効にします(デフォルトで有効)。

PY_COERCE_C_LOCALE マクロは定義しないでください。



Disable all freelists except the empty tuple singleton.

Added in version 3.11.


Python のライブラリディレクトリ名(デフォルトは lib )。

Fedora と SuSE は64ビットプラットフォームで lib64 を使用します。

sys.platlibdir を参照してください。

Added in version 3.9.


ensurepip モジュールが使用する wheel パッケージのディレクトリです(デフォルトはなし)。

Linux ディストリビューションのパッケージングポリシーの中には、依存関係をバンドルすることを推奨しているものがあります。例えば、 Fedora は wheel パッケージを /usr/share/python-wheels/ ディレクトリにインストールし、 ensurepip._bundled パッケージはインストールしません。

Added in version 3.10.


configure がビルドの依存関係を検出するために pkg-config を使用するかどうかを設定します。

  • check (デフォルト): pkg-config はオプションです。

  • yes : pkg-config は必須です。

  • no : pkg-config が存在しても、 configure は使用しません。

Added in version 3.11.


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.


  • 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.

統計情報を読むには Tools/scripts/summarize_stats.py を使用してください。


  • 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.

Added in version 3.11.


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.

Added in version 3.13.


Path to pkg-config utility.


pkg-config options.

3.3.2. C compiler options


C compiler command.


C compiler flags.


C preprocessor command.


C preprocessor flags, e.g. -Iinclude_dir.

3.3.3. Linker options


Linker flags, e.g. -Llibrary_directory.


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


Name for machine-dependent library files.

3.3.4. Options for third-party dependencies

Added in version 3.11.


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


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


C compiler and linker flags for gdbm.


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


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


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


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


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


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


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


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


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


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.


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


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

3.3.5. WebAssembly オプション


wasm32-emscripten のビルドフレーバーを設定します。

  • browser (デフォルト): 最小限の stdlib 、デフォルトの MEMFS をプリロードします。

  • node: NODERAWFS と pthread をサポートします。

Added in version 3.11.


WASM のダイナミックリンクサポートをオンにします。

ダイナミックリンクにより dlopen が可能になります。デッドコードの排除や機能追加に制限があるため、実行ファイルのファイルサイズが大きくなります。

Added in version 3.11.


WASM の pthreads サポートをオンにします。

Added in version 3.11.

3.3.6. インストールオプション


アーキテクチャに依存しないファイルを PREFIX にインストールします。Unix の場合、デフォルトは /usr/local です。

この値は、実行時に sys.prefix を使って取得することができます。

例として、 --prefix="$HOME/.local/" を使用すると、 Python をそのホームディレクトリにインストールすることができます。


アーキテクチャ依存のファイルを EPREFIX にインストールします。デフォルトは --prefix です。

この値は、実行時に sys.exec_prefix を使って取得することができます。


test パッケージや _testcapi 拡張モジュール(デフォルトでビルド、インストールされます)のようなテストモジュールをビルド、インストールしないようにします。

Added in version 3.10.


Python のインストール時に実行される ensurepip コマンドを選択します:

  • upgrade (デフォルト): python -m ensurepip --altinstall --upgrade コマンドを実行します。

  • install: python -m ensurepip --altinstall コマンドを実行します。

  • no: ensurepip を実行しない;

Added in version 3.6.

3.3.7. パフォーマンスに関するオプション

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.


PROFILE_TASK を使用して Profile Guided Optimization (PGO) を有効にします(デフォルトでは無効です)。

Cコンパイラの Clang では、 PGO のために llvm-profdata プログラムが必要です。macOS では、 GCC もこれを必要とします: GCC は macOS の Clang のエイリアスにすぎません。

Disable also semantic interposition in libpython if --enable-shared and GCC is used: add -fno-semantic-interposition to the compiler and linker flags.


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.

バージョン 3.10 で変更: GCC で -fno-semantic-interposition を使用する。


Environment variable used in the Makefile: Python command line arguments for the PGO generation task.

デフォルト: -m test --pgo --timeout=$(TESTTIMEOUT)

Added in version 3.8.

バージョン 3.13 で変更: Task failure is no longer ignored silently.


Enable Link Time Optimization (LTO) in any build (disabled by default).

The C compiler Clang requires llvm-ar for LTO (ar on macOS), as well as an LTO-aware linker (ld.gold or lld).

Added in version 3.6.

Added in version 3.11: To use ThinLTO feature, use --with-lto=thin on Clang.

バージョン 3.12 で変更: Use ThinLTO as the default optimization policy on Clang if the compiler accepts the flag.


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.


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

Added in version 3.12.


Arguments to llvm-bolt when instrumenting binaries.

Added in version 3.12.


Enable computed gotos in evaluation loop (enabled by default on supported compilers).


Disable the fast mimalloc allocator (enabled by default).

See also PYTHONMALLOC environment variable.


Disable the specialized Python memory allocator pymalloc (enabled by default).

See also PYTHONMALLOC environment variable.


Disable static documentation strings to reduce the memory footprint (enabled by default). Documentation strings defined in Python are not affected.

Don't define the WITH_DOC_STRINGS macro.

See the PyDoc_STRVAR() macro.


Enable C-level code profiling with gprof (disabled by default).


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

3.3.8. Python Debug Build

A debug build is Python built with the --with-pydebug configure option.

Effects of a debug build:

  • Display all warnings by default: the list of default warning filters is empty in the warnings module.

  • Add d to sys.abiflags.

  • Add sys.gettotalrefcount() function.

  • Add -X showrefcount command line option.

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

  • Add support for the __lltrace__ variable: enable low-level tracing in the bytecode evaluation loop if the variable is defined.

  • Install debug hooks on memory allocators to detect buffer overflow and other memory errors.

  • Define Py_DEBUG and Py_REF_DEBUG macros.

  • Add runtime checks: code surrounded by #ifdef Py_DEBUG and #endif. Enable assert(...) and _PyObject_ASSERT(...) assertions: don't set the NDEBUG macro (see also the --with-assertions configure option). Main runtime checks:

    • Add sanity checks on the function arguments.

    • Unicode and int objects are created with their memory filled with a pattern to detect usage of uninitialized objects.

    • Ensure that functions which can clear or replace the current exception are not called with an exception raised.

    • Check that deallocator functions don't change the current exception.

    • The garbage collector (gc.collect() function) runs some basic checks on objects consistency.

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

See also the Python Development Mode and the --with-trace-refs configure option.

バージョン 3.8 で変更: 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


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


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


  • 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.

Added in version 3.8.

バージョン 3.13 で変更: This build is now ABI compatible with release build and debug build.


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.


Enable Valgrind support (default is no).


Enable DTrace support (default is no).

See Instrumenting CPython with DTrace and SystemTap.

Added in version 3.6.


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

Added in version 3.6.


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

Added in version 3.6.


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

Added in version 3.6.


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

Added in version 3.13.

3.3.10. Linker options


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


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

Added in version 3.10.

3.3.11. Libraries options

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

Link against additional libraries (default is no).


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


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

Added in version 3.3.

バージョン 3.13 で変更: Default to using the installed mpdecimal library.

バージョン 3.13 で非推奨、バージョン 3.15 で削除予定: A copy of the mpdecimal library sources will no longer be distributed with Python 3.15.


Designate a backend library for the readline module.

  • readline: Use readline as the backend.

  • editline: Use editline as the backend.

Added in version 3.10.


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

Don't define the HAVE_LIBREADLINE macro.

Added in version 3.10.


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


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


Root of the OpenSSL directory.

Added in version 3.7.


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.

3.3.12. Security Options


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.


Built-in hash modules:

  • md5;

  • sha1;

  • sha256;

  • sha512;

  • sha3 (with shake);

  • blake2.

Added in version 3.9.


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.

バージョン 3.10 で変更: The settings python and STRING also set TLS 1.2 as minimum protocol version.

3.3.13. macOS のオプション

See Mac/README.rst.


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


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


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


  • universal2;

  • 32-bit;

  • 64-bit;

  • 3-way;

  • intel;

  • intel-32;

  • intel-64;

  • all


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


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.

Added in version 3.13.

3.3.14. iOS のオプション

iOS/README.rst を参照。


Python.framework を作成します。 macOS とは違い、インストールパスを指定する INSTALLDIR 引数は必須です。


フレームワークの名前を指定します (デフォルト: Python) 。

3.3.15. クロスコンパイルのオプション

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.


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


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


path to build python binary for cross compiling

Added in version 3.11.


An environment variable that points to a file with configure overrides.

Example config.site file:

# config.site-aarch64

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

Added in version 3.11.


CONFIG_SITE=config.site-aarch64 ../configure \
    --build=x86_64-pc-linux-gnu \
    --host=aarch64-unknown-linux-gnu \

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

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. 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. 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 clean

Remove built files. make distclean

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

Build the all target and install Python. 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). 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. 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__

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


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

Added in version 3.6.


(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.


Added in version 3.4.


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


C compiler command.

Example: gcc -pthread.


C++ compiler command.

Example: g++ -pthread.


C compiler flags.


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.


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

Added in version 3.12.


Extra C compiler flags.


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

Added in version 3.2.


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

Added in version 3.5.


Base compiler flags.


Optimization flags.


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

Added in version 3.7.


Compiler flags used to build a shared library.

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


Extra C flags added for building the interpreter object files.

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




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

Added in version 3.5.


C flags used for building the interpreter object files.


Added in version 3.7.



Added in version 3.2.


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


Added in version 3.8.


Purify command. Purify is a memory debugger program.

Default: empty string (not used).

3.5.3. Linker flags


Linker command used to build programs like python and _testembed.

Default: $(PURIFY) $(CC).


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 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.


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

Added in version 3.8.


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.


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

Example: -lrt.


Command to build a shared library.



Command to build libpython shared library.






Added in version 3.8.


Linker flags used for building the interpreter object files.

Added in version 3.8.