# 3. Python を構成する

## 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.

バージョン 3.5 で変更: On Windows, Visual Studio 2015 or later is 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.

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.

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

--enable-loadable-sqlite-extensions

  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.

--disable-ipv6

  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。

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

  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。

  デフォルトでは、桁の大きさは30です。

  `PYLONG_BITS_IN_DIGIT` を `15` 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。

--with-suffix=SUFFIX

  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.

--without-decimal-contextvar

  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`。

--without-c-locale-coercion

  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。

  `PYTHONCOERCECLOCALE` および PEP 538 を参照してください。

--without-freelists

  Disable all freelists except the empty tuple singleton.

  Added in version 3.11.

--with-platlibdir=DIRNAME

  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.

--with-wheel-pkg-dir=PATH

  `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.

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

  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.

--enable-pystats

  Turn on internal statistics gathering.

  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.

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

  Added in version 3.11.

### 3.3.2. WebAssembly オプション

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

  `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.

--enable-wasm-dynamic-linking

  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.

--enable-wasm-pthreads

  WASM の pthreads サポートをオンにします。

  Added in version 3.11.

### 3.3.3. インストールオプション

--prefix=PREFIX

  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。

--exec-prefix=EPREFIX

  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。

--disable-test-modules

  `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.

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

  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.

### 3.3.4. 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.

--enable-optimizations

  `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.

  注釈

  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。

PROFILE_TASK

  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.

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

  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-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

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

--without-pymalloc

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

  See also `PYTHONMALLOC` environment variable.

--without-doc-strings

  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-profiling

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

--with-strict-overflow

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

### 3.3.5. 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), 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.

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

### 3.3.10. macOS のオプション

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.

  オプション:

  - `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. 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.

--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

クロスコンパイルの例:

    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.