3. Configure Python (original) (raw)
3.1. Build Requirements¶
Features and minimum versions required to build CPython:
- A C11 compiler. Optional C11 featuresare not required.
- On Windows, Microsoft Visual Studio 2017 or later is required.
- Support for IEEE 754floating-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.
Changed in version 3.1: Tcl/Tk version 8.3.1 is now required.
Changed in version 3.5: On Windows, Visual Studio 2015 or later is now required. Tcl/Tk version 8.4 is now required.
Changed in version 3.6: Selected C99 features are now required, like <stdint.h>
and static inline
functions.
Changed in version 3.7: Thread support and OpenSSL 1.0.2 are now required.
Changed in version 3.10: OpenSSL 1.1.1 is now required. Require SQLite 3.7.15.
Changed in 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.
Changed in 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:
The generated files can change depending on the exact autoconf-archive
,aclocal
and pkg-config
versions.
3.3. Configure Options¶
List all configure
script options using:
See also the Misc/SpecialBuilds.txt
in the Python source distribution.
3.3.1. General Options¶
--enable-loadable-sqlite-extensions¶
Support loadable extensions in the _sqlite
extension module (default is no) of the sqlite3 module.
See the sqlite3.Connection.enable_load_extension() method of thesqlite3 module.
Added in version 3.6.
--disable-ipv6¶
Disable IPv6 support (enabled by default if supported), see thesocket module.
--enable-big-digits=[15|30]¶
Define the size in bits of Python int digits: 15 or 30 bits.
By default, the digit size is 30.
Define the PYLONG_BITS_IN_DIGIT
to 15
or 30
.
See sys.int_info.bits_per_digit.
--with-suffix=SUFFIX¶
Set the Python executable suffix to SUFFIX.
The default suffix is .exe
on Windows and macOS (python.exe
executable), .js
on Emscripten node, .html
on Emscripten browser,.wasm
on WASI, and an empty string on other platforms (python
executable).
Changed in version 3.11: The default suffix on WASM platform is one of .js
, .html
or .wasm
.
--with-tzpath=¶
Select the default time zone search path for zoneinfo.TZPATH. See the Compile-time configuration of the zoneinfo module.
Default: /usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo
.
See os.pathsep path separator.
Added in version 3.9.
--without-decimal-contextvar¶
Build the _decimal
extension module using a thread-local context rather than a coroutine-local context (default), see the decimal module.
See decimal.HAVE_CONTEXTVAR and the contextvars module.
Added in version 3.9.
--with-dbmliborder=¶
Override order to check db backends for the [dbm](../library/dbm.html#module-dbm "dbm: Interfaces to various Unix "database" formats.") module
A valid value is a colon (:
) separated string with the backend names:
ndbm
;gdbm
;bdb
.
--without-c-locale-coercion¶
Disable C locale coercion to a UTF-8 based locale (enabled by default).
Don’t define the PY_COERCE_C_LOCALE
macro.
See PYTHONCOERCECLOCALE and the PEP 538.
--without-freelists¶
Disable all freelists except the empty tuple singleton.
Added in version 3.11.
--with-platlibdir=DIRNAME¶
Python library directory name (default is lib
).
Fedora and SuSE use lib64
on 64-bit platforms.
See sys.platlibdir.
Added in version 3.9.
--with-wheel-pkg-dir=PATH¶
Directory of wheel packages used by the [ensurepip](../library/ensurepip.html#module-ensurepip "ensurepip: Bootstrapping the "pip" installer into an existing Python installation or virtual environment.") module (none by default).
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 theensurepip._bundled
package.
Added in version 3.10.
--with-pkg-config=[check|yes|no]¶
Whether configure should use pkg-config to detect build dependencies.
check
(default): pkg-config is optionalyes
: pkg-config is mandatoryno
: configure does not use pkg-config even when present
Added in 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.
Use Tools/scripts/summarize_stats.py
to read the stats.
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.
Added in version 3.11.
--disable-gil¶
Enables experimental support for running Python without theglobal interpreter lock (GIL): free threading build.
Defines the Py_GIL_DISABLED
macro and adds "t"
tosys.abiflags.
See Free-threaded CPython for more detail.
Added in 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
.
Note
When building CPython with JIT enabled, ensure that your system has Python 3.11 or later installed.
Added in 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. -I_includedir_
.
3.3.3. Linker options¶
LDFLAGS¶
Linker flags, e.g. -L_librarydirectory_
.
LIBS¶
Libraries to pass to the linker, e.g. -l_library_
.
MACHDEP¶
Name for machine-dependent library files.
3.3.4. Options for third-party dependencies¶
Added in version 3.11.
BZIP2_CFLAGS¶
BZIP2_LIBS¶
C compiler and linker flags to link Python to libbz2
, used by bz2module, overriding pkg-config
.
CURSES_CFLAGS¶
CURSES_LIBS¶
C compiler and linker flags for libncurses
or libncursesw
, used bycurses 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 readlinemodule, overriding pkg-config
.
LIBSQLITE3_CFLAGS¶
LIBSQLITE3_LIBS¶
C compiler and linker flags for libsqlite3
, used by sqlite3module, 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 bycurses.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. WebAssembly Options¶
--with-emscripten-target=[browser|node]¶
Set build flavor for wasm32-emscripten
.
browser
(default): preload minimal stdlib, default MEMFS.node
: NODERAWFS and pthread support.
Added in version 3.11.
--enable-wasm-dynamic-linking¶
Turn on dynamic linking support for WASM.
Dynamic linking enables dlopen
. File size of the executable increases due to limited dead code elimination and additional features.
Added in version 3.11.
--enable-wasm-pthreads¶
Turn on pthreads support for WASM.
Added in version 3.11.
3.3.6. Install Options¶
--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="$HOME/.local/"
to install a Python in its home directory.
--exec-prefix=EPREFIX¶
Install architecture-dependent files in EPREFIX, defaults to --prefix.
This value can be retrieved at runtime using sys.exec_prefix.
--disable-test-modules¶
Don’t build nor install test modules, like the test package or the_testcapi
extension module (built and installed by default).
Added in version 3.10.
--with-ensurepip=[upgrade|install|no]¶
Select the [ensurepip](../library/ensurepip.html#module-ensurepip "ensurepip: Bootstrapping the "pip" installer into an existing Python installation or virtual environment.") command run on Python installation:
upgrade
(default): runpython -m ensurepip --altinstall --upgrade
command.install
: runpython -m ensurepip --altinstall
command;no
: don’t run ensurepip;
Added in version 3.6.
3.3.7. Performance options¶
Configuring Python using --enable-optimizations --with-lto
(PGO + LTO) is recommended for best performance. The experimental --enable-bolt
flag can also be used to improve performance.
--enable-optimizations¶
Enable Profile Guided Optimization (PGO) using PROFILE_TASK(disabled by default).
The C compiler Clang requires llvm-profdata
program for PGO. On macOS, GCC also requires it: GCC is just an alias to Clang on macOS.
Disable also semantic interposition in libpython if --enable-shared
and GCC is used: add -fno-semantic-interposition
to the compiler and linker flags.
Note
During the build, you may encounter compiler warnings about profile data not being available for some source files. These warnings are harmless, as only a subset of the code is exercised during profile data acquisition. To disable these warnings on Clang, manually suppress them by adding-Wno-profile-instr-unprofiled
to CFLAGS.
Added in version 3.6.
Changed in version 3.10: Use -fno-semantic-interposition
on GCC.
PROFILE_TASK¶
Environment variable used in the Makefile: Python command line arguments for the PGO generation task.
Default: -m test --pgo --timeout=$(TESTTIMEOUT)
.
Added in version 3.8.
Changed in version 3.13: Task failure is no longer ignored silently.
--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.
Changed in 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.
BOLT_APPLY_FLAGS¶
Arguments to llvm-bolt
when creating a BOLT optimized binary.
Added in version 3.12.
BOLT_INSTRUMENT_FLAGS¶
Arguments to llvm-bolt
when instrumenting binaries.
Added in version 3.12.
--with-computed-gotos¶
Enable computed gotos in evaluation loop (enabled by default on supported compilers).
--without-mimalloc¶
Disable the fast mimalloc allocator (enabled by default).
See also PYTHONMALLOC environment variable.
--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).
3.3.8. 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 allocatorsto detect buffer overflow and other memory errors.
- Define
Py_DEBUG
andPy_REF_DEBUG
macros. - Add runtime checks: code surrounded by
#ifdef Py_DEBUG
and#endif
. Enableassert(...)
and_PyObject_ASSERT(...)
assertions: don’t set theNDEBUG
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.
Changed in version 3.8: Release builds and debug builds are now ABI compatible: defining thePy_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.
Added in version 3.8.
Changed in 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.
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.
--with-thread-sanitizer¶
Enable ThreadSanitizer data race detector, tsan
(default is no).
Added in 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).
Added in 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).
Added in version 3.3.
Changed in 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.
See also
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.
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 andpkg-config
;- DIR: set an explicit rpath.
Added in 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
.
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.
Changed in 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
(x86-64 and arm64);32-bit
(PPC and i386);64-bit
(PPC64 and x86-64);3-way
(i386, PPC and x86-64);intel
(i386 and x86-64);intel-32
(i386);intel-64
(x86-64);all
(PPC, i386, PPC64 and x86-64).
Note that values for this configuration item are not the same as the identifiers used for universal binary wheels on macOS. See the Python Packaging User Guide for details on the packaging platform compatibility tags used on macOS
--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.
Added in 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
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
HOSTRUNNER¶
Program to run CPython for the host platform for cross-compilation.
Added in 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 byconfigure
);pyconfig.h
(created byconfigure
);Modules/Setup
: C extensions built by the Makefile usingModule/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 staticlibpython
library are linked into the finalpython
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 executemake
, 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. Theconfigure
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 justmake
).
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 "", line 1, in 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()
andPyMODINIT_FUNC macros of Include/exports.h
are defined differently depending if the Py_BUILD_CORE_MODULE
macro is defined:
- Use
Py_EXPORTED_SYMBOL
if thePy_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 byMakefile
.
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. -I_includedir_
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 <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mo stretchy="false">(</mo><mi>C</mi><mi>O</mi><mi>N</mi><mi>F</mi><mi>I</mi><mi>G</mi><mi>U</mi><mi>R</mi><msub><mi>E</mi><mi>C</mi></msub><mi>P</mi><mi>P</mi><mi>F</mi><mi>L</mi><mi>A</mi><mi>G</mi><mi>S</mi><mo stretchy="false">)</mo></mrow><annotation encoding="application/x-tex">(CONFIGURE_CPPFLAGS) </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mopen">(</span><span class="mord mathnormal" style="margin-right:0.13889em;">CONF</span><span class="mord mathnormal" style="margin-right:0.07847em;">I</span><span class="mord mathnormal">G</span><span class="mord mathnormal" style="margin-right:0.10903em;">U</span><span class="mord mathnormal" style="margin-right:0.00773em;">R</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.05764em;">E</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3283em;"><span style="top:-2.55em;margin-left:-0.0576em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.07153em;">C</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.13889em;">PPF</span><span class="mord mathnormal">L</span><span class="mord mathnormal">A</span><span class="mord mathnormal" style="margin-right:0.05764em;">GS</span><span class="mclose">)</span></span></span></span>(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 ofCFLAGS 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 inCFLAGS 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 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) <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mo stretchy="false">(</mo><mi>O</mi><mi>P</mi><mi>T</mi><mo stretchy="false">)</mo></mrow><annotation encoding="application/x-tex">(OPT) </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mopen">(</span><span class="mord mathnormal" style="margin-right:0.13889em;">OPT</span><span class="mclose">)</span></span></span></span>(CONFIGURE_CFLAGS) <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mo stretchy="false">(</mo><mi>C</mi><mi>F</mi><mi>L</mi><mi>A</mi><mi>G</mi><mi>S</mi><mo stretchy="false">)</mo></mrow><annotation encoding="application/x-tex">(CFLAGS) </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mopen">(</span><span class="mord mathnormal" style="margin-right:0.13889em;">CF</span><span class="mord mathnormal">L</span><span class="mord mathnormal">A</span><span class="mord mathnormal" style="margin-right:0.05764em;">GS</span><span class="mclose">)</span></span></span></span>(EXTRA_CFLAGS)
.
PY_CFLAGS_NODIST¶
Default: $(CONFIGURE_CFLAGS_NODIST) <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mo stretchy="false">(</mo><mi>C</mi><mi>F</mi><mi>L</mi><mi>A</mi><mi>G</mi><msub><mi>S</mi><mi>N</mi></msub><mi>O</mi><mi>D</mi><mi>I</mi><mi>S</mi><mi>T</mi><mo stretchy="false">)</mo><mo>−</mo><mi>I</mi></mrow><annotation encoding="application/x-tex">(CFLAGS_NODIST) -I</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mopen">(</span><span class="mord mathnormal" style="margin-right:0.13889em;">CF</span><span class="mord mathnormal">L</span><span class="mord mathnormal">A</span><span class="mord mathnormal">G</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.05764em;">S</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3283em;"><span style="top:-2.55em;margin-left:-0.0576em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.10903em;">N</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.02778em;">O</span><span class="mord mathnormal" style="margin-right:0.02778em;">D</span><span class="mord mathnormal" style="margin-right:0.07847em;">I</span><span class="mord mathnormal" style="margin-right:0.13889em;">ST</span><span class="mclose">)</span><span class="mspace" style="margin-right:0.2222em;"></span><span class="mbin">−</span><span class="mspace" style="margin-right:0.2222em;"></span></span><span class="base"><span class="strut" style="height:0.6833em;"></span><span class="mord mathnormal" style="margin-right:0.07847em;">I</span></span></span></span>(srcdir)/Include/internal
.
Added in version 3.5.
PY_STDMODULE_CFLAGS¶
C flags used for building the interpreter object files.
Default: $(PY_CFLAGS) <span class="katex"><span class="katex-mathml"><math xmlns="http://www.w3.org/1998/Math/MathML"><semantics><mrow><mo stretchy="false">(</mo><mi>P</mi><msub><mi>Y</mi><mi>C</mi></msub><mi>F</mi><mi>L</mi><mi>A</mi><mi>G</mi><msub><mi>S</mi><mi>N</mi></msub><mi>O</mi><mi>D</mi><mi>I</mi><mi>S</mi><mi>T</mi><mo stretchy="false">)</mo></mrow><annotation encoding="application/x-tex">(PY_CFLAGS_NODIST) </annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:1em;vertical-align:-0.25em;"></span><span class="mopen">(</span><span class="mord mathnormal" style="margin-right:0.13889em;">P</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.22222em;">Y</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3283em;"><span style="top:-2.55em;margin-left:-0.2222em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.07153em;">C</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.13889em;">F</span><span class="mord mathnormal">L</span><span class="mord mathnormal">A</span><span class="mord mathnormal">G</span><span class="mord"><span class="mord mathnormal" style="margin-right:0.05764em;">S</span><span class="msupsub"><span class="vlist-t vlist-t2"><span class="vlist-r"><span class="vlist" style="height:0.3283em;"><span style="top:-2.55em;margin-left:-0.0576em;margin-right:0.05em;"><span class="pstrut" style="height:2.7em;"></span><span class="sizing reset-size6 size3 mtight"><span class="mord mathnormal mtight" style="margin-right:0.10903em;">N</span></span></span></span><span class="vlist-s"></span></span><span class="vlist-r"><span class="vlist" style="height:0.15em;"><span></span></span></span></span></span></span><span class="mord mathnormal" style="margin-right:0.02778em;">O</span><span class="mord mathnormal" style="margin-right:0.02778em;">D</span><span class="mord mathnormal" style="margin-right:0.07847em;">I</span><span class="mord mathnormal" style="margin-right:0.13889em;">ST</span><span class="mclose">)</span></span></span></span>(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 asCFLAGS_NODIST. Use it when a linker flag should not be part ofLDFLAGS 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 inLDFLAGS 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. -L_libdir_
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.
Footnotes