3.1. Build Requirements
To build CPython, you will need:
A
compiler.
are not required.
On Windows, Microsoft Visual Studio 2017 or later is required.
Support for
floating-point numbers and
floating-point Not-a-Number (NaN)
.
Support for threads.
Changed in version 3.5: On Windows, Visual Studio 2015 or later is now required.
Changed in version 3.6: Selected C99 features, like <stdint.h> and staticinline functions, are now required.
Changed in version 3.7: Thread support is now required.
Changed in version 3.11: C11 compiler, IEEE 754 and NaN support are now required. On Windows, Visual Studio 2017 or later is required.
See also
“Style Guide for C Code” and
“CPython platform support”.
3.1.1. Requirements for optional modules
Some
of the standard library require third-party libraries installed for development (for example, header files must be available).
Missing requirements are reported in the configure output. Modules that are missing due to missing dependencies are listed near the end of the make output, sometimes using an internal name, for example, _ctypes for
module.
If you distribute a CPython interpreter without optional modules, it’s best practice to advise users, who generally expect that standard library modules are available.
Dependencies to build optional modules are:
Dependency
Minimum version
Python module
or
3.3.0 recommended
2.5.0
or
_uuid
3.0.18 recommended
(1.1.1 minimum)
,
3.15.2
8.5.12
,
,
,
, or
1.2.2.1 (zlib, zlib-ng)
0.6.0 (zlib-rs)
,
,
1.4.5
Note that the table does not include all optional modules; in particular, platform-specific modules like
are not listed here.
See also
The
includes a full list of dependencies required to build all modules and instructions on how to install them on common platforms.
allows building with an external
library.
Options for third-party dependencies
Changed in version 3.1: Tcl/Tk version 8.3.1 is now required for
.
Changed in version 3.5: Tcl/Tk version 8.4 is now required for
.
Changed in version 3.7: OpenSSL 1.0.2 is now required for
and
.
Changed in version 3.10: OpenSSL 1.1.1 is now required for
and
. SQLite 3.7.15 is now required for
.
Changed in version 3.11: Tcl/Tk version 8.5.12 is now required for
.
Changed in version 3.13: SQLite 3.15.2 is now required for
.
3.2. Generated files
To reduce build dependencies, Python source code contains multiple generated files. Commands to regenerate all generated files:
makeregen-all makeregen-stdlib-module-names makeregen-limited-abi makeregen-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 makeregen-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 versions of the tools used. The container that CPython uses has
2.72, aclocal from
1.16.5, and
1.8.1.
Changed in version 3.13: Autoconf 2.71 and aclocal 1.16.5 and are now used to regenerate configure.
Changed in version 3.14: Autoconf 2.72 is now used to regenerate configure.
3.3. Configure Options
List all configure script options using:
./configure--help 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
module.
See the
sqlite3.Connection.enable_load_extension()
method of the
module.
Added in version 3.6.
--disable-ipv6
Disable IPv6 support (enabled by default if supported), see the
module.
--enable-big-digits=[15|30]
Define the size in bits of Python
digits: 15 or 30 bits.
By default, the digit size is 30.
Define the PYLONG_BITS_IN_DIGIT to 15 or 30.
See
.
--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=<listofabsolutepathsseparatedbypathsep>
Select the default time zone search path for
. See the
of the
module.
Default: /usr/share/zoneinfo:/usr/lib/zoneinfo:/usr/share/lib/zoneinfo:/etc/zoneinfo.
See
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
module.
See
and the
module.
Added in version 3.9.
--with-dbmliborder=<listofbackendnames>
Override order to check db backends for the
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
and the
.
--with-platlibdir=DIRNAME
Python library directory name (default is lib).
Fedora and SuSE use lib64 on 64-bit platforms.
See
.
Added in version 3.9.
--with-wheel-pkg-dir=PATH
Directory of wheel packages used by the
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 the ensurepip._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 optional
yes: pkg-config is mandatory
no: configure does not use pkg-config even when present
Added in version 3.11.
--with-missing-stdlib-config=FILE
Path to a
configuration file containing custom error messages for missing
modules.
This option is intended for Python distributors who wish to provide distribution-specific guidance when users encounter standard library modules that are missing or packaged separately.
The JSON file should map missing module names to custom error message strings. For example, if your distribution packages
and
separately and excludes _gdbm for legal reasons, the configuration could contain:
{"_gdbm":"The '_gdbm' module is not available in this distribution","tkinter":"Install the python-tk package to use tkinter","_tkinter":"Install the python-tk package to use tkinter",}Added in version 3.15.
--enable-pystats
Turn on internal Python performance statistics gathering.
By default, statistics gathering is off. Use python3-Xpystats 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
command line option.
Add PYTHONSTATS environment variable.
Define the Py_STATS macro.
Add functions to the
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 support for running Python without the
(GIL):
.
Defines the Py_GIL_DISABLED macro and adds "t" to
.
See
for more detail.
Added in version 3.13.
--enable-experimental-jit=[no|yes|yes-off|interpreter]
Indicate how to integrate the
experimental just-in-time compiler
.
no: Don’t build the JIT.
yes: Enable the JIT. To disable it at runtime, set the environment variable
.
yes-off: Build the JIT, but disable it by default. To enable it at runtime, set the environment variable
.
interpreter: Enable the “JIT interpreter” (only useful for those debugging the JIT itself). To disable it at runtime, set the environment variable
.
--enable-experimental-jit=no is the default behavior if the option is not provided, and --enable-experimental-jit is shorthand for --enable-experimental-jit=yes. See Tools/jit/README.md for more information, including how to install the necessary build-time dependencies.
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.
--disable-epoll
Build without epoll, meaning that
will not be present even if the system provides an
function. This may be used on systems where epoll_create or
is available but incompatible with Linux semantics.
Added in version 3.15.
--with-build-details-suffix=[yes|SUFFIX]
Rename build-details.json to permit multiple co-located Python installs. If a custom SUFFIX is supplied it is used verbatim, otherwise one will be generated from the MULTIARCH tag with -free-threading and -debug, as appropriate.
Added in version 3.16.
3.3.2. C compiler options
CC
C compiler command.
CFLAGS
C compiler flags.
CPP
C preprocessor command.
CPPFLAGS
C preprocessor flags, e.g. -Iinclude_dir.
3.3.3. Linker options
LDFLAGS
Linker flags, e.g. -Llibrary_directory.
LIBS
Libraries to pass to the linker, e.g. -llibrary.
MACHDEP
Name for machine-dependent library files.
3.3.4. Options for third-party dependencies
Added in version 3.11.
BZIP2_CFLAGS
BZIP2_LIBS
C compiler and linker flags to link Python to libbz2, used by
module, overriding pkg-config.
CURSES_CFLAGS
CURSES_LIBS
C compiler and linker flags for libncurses or libncursesw, used by
module, overriding pkg-config.
GDBM_CFLAGS
GDBM_LIBS
C compiler and linker flags for gdbm.
LIBEDIT_CFLAGS
LIBEDIT_LIBS
C compiler and linker flags for libedit, used by
module, overriding pkg-config.
LIBFFI_CFLAGS
LIBFFI_LIBS
C compiler and linker flags for libffi, used by
module, overriding pkg-config.
LIBMPDEC_CFLAGS
LIBMPDEC_LIBS
C compiler and linker flags for libmpdec, used by
module, overriding pkg-config.
LIBLZMA_CFLAGS
LIBLZMA_LIBS
C compiler and linker flags for liblzma, used by
module, overriding pkg-config.
LIBREADLINE_CFLAGS
LIBREADLINE_LIBS
C compiler and linker flags for libreadline, used by
module, overriding pkg-config.
LIBSQLITE3_CFLAGS
LIBSQLITE3_LIBS
C compiler and linker flags for libsqlite3, used by
module, overriding pkg-config.
LIBUUID_CFLAGS
LIBUUID_LIBS
C compiler and linker flags for libuuid, used by
module, overriding pkg-config.
LIBZSTD_CFLAGS
LIBZSTD_LIBS
C compiler and linker flags for libzstd, used by
module, overriding pkg-config.
Added in version 3.14.
PANEL_CFLAGS
PANEL_LIBS
C compiler and linker flags for PANEL, overriding pkg-config.
C compiler and linker flags for libpanel or libpanelw, used by
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
module, overriding pkg-config.
3.3.5. WebAssembly Options
--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
.
As an example, one can use --prefix="$HOME/.local/" to install a Python in its home directory.
--exec-prefix=EPREFIX
Install architecture-dependent files in EPREFIX, defaults to
.
This value can be retrieved at runtime using
.
--disable-test-modules
Don’t build nor install test modules, like the
package or the _testcapi extension module (built and installed by default).
Added in version 3.10.
--with-ensurepip=[upgrade|install|no]
Select the
command run on Python installation:
upgrade (default): run python-mensurepip--altinstall--upgrade command.
install: run python-mensurepip--altinstall command;
no: don’t run ensurepip;
Added in version 3.6.
3.3.7. Performance options
Configuring Python using --enable-optimizations--with-lto (PGO + LTO) is recommended for best performance. The experimental --enable-bolt flag can also be used to improve performance.
--enable-optimizations
Enable Profile Guided Optimization (PGO) using
(disabled by default).
The C compiler Clang requires llvm-profdata program for PGO. On macOS, GCC also requires it: GCC is just an alias to Clang on macOS.
Disable also semantic interposition in libpython if --enable-shared and GCC is used: add -fno-semantic-interposition to the compiler and linker flags.
Note
During the build, you may encounter compiler warnings about profile data not being available for some source files. These warnings are harmless, as only a subset of the code is exercised during profile data acquisition. To disable these warnings on Clang, manually suppress them by adding -Wno-profile-instr-unprofiled to
.
Added in version 3.6.
Changed in version 3.10: Use -fno-semantic-interposition on GCC.
PROFILE_TASK
Environment variable used in the Makefile: Python command line arguments for the PGO generation task.
Default: -mtest--pgo--timeout=$(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_FLAGSconfigure 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
.
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).
--with-tail-call-interp
Enable interpreters using tail calls in CPython. If enabled, enabling PGO (
) is highly recommended. This option specifically requires a C compiler with proper tail call support, and the
calling convention. For example, Clang 19 and newer supports this feature.
Added in version 3.14.
--without-frame-pointers
Disable frame pointers, which are enabled by default (see
).
By default, the build appends flags to generate frame or backchain pointers to BASECFLAGS:
-fno-omit-frame-pointer and/or -mno-omit-leaf-frame-pointer are added when the compiler supports them.
-marm and/or -mno-thumb is added on 32-bit ARM when supported,
on s390x platforms, when supported, -mbackchain is added instead. of the above frame pointer flags.
on ppc64le platforms, no compiler flags is needed since the power ABI requires that compilers maintain a back chain by default.
Frame pointers enable profilers, debuggers, and system tracing tools (perf, eBPF, dtrace, gdb) to walk the C call stack without DWARF metadata. The flags propagate to third-party C extensions through
. On compilers that do not understand them, the build silently skips them.
Downstream packagers and authors of native libraries built with custom build systems should set the same flags so the unwind chain stays unbroken across all native frames.
Added in version 3.15.
--without-mimalloc
Disable the fast
allocator (enabled by default).
This option cannot be used together with
because the
build requires mimalloc.
See also
environment variable.
--without-pymalloc
Disable the specialized Python memory allocator
(enabled by default).
See also
environment variable.
--with-pymalloc-hugepages
Enable huge page support for
arenas (disabled by default). When enabled, the arena size on 64-bit platforms is increased to 2 MiB and arena allocation uses MAP_HUGETLB (Linux) or MEM_LARGE_PAGES (Windows) with automatic fallback to regular pages.
Even when compiled with this option, huge pages are not used at runtime unless the
environment variable is set to 1. This opt-in is required because huge pages
carry risks on Linux: if the huge-page pool is exhausted, page faults (including copy-on-write faults after
) deliver SIGBUS and kill the process.
need a special privilege on Windows. See the
Windows documentation for large pages
for details. Python will fail on startup if the required privilege
is not held by the user.
The configure script checks that the platform supports MAP_HUGETLB and emits a warning if it is not available.
On Windows, use the --pymalloc-hugepages flag with build.bat or set the UsePymallocHugepages MSBuild property.
Added in version 3.15.
--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).
--without-remote-debug
Deactivate remote debugging support described in
(enabled by default). When this flag is provided the code that allows the interpreter to schedule the execution of a Python file in a separate process as described in
is not compiled. This includes both the functionality to schedule code to be executed and the functionality to receive code to be executed.
Py_REMOTE_DEBUG
This macro is defined by default, unless Python is configured with
.
Note that even if the macro is defined, remote debugging may not be available (for example, on an incompatible platform).
Added in version 3.14.
3.3.8. Python Debug Build
A debug build is Python built with the
configure option.
Effects of a debug build:
Display all warnings by default: the list of default warning filters is empty in the
module.
Add d to
.
Add sys.gettotalrefcount() function.
Add
command line option.
Add
command line option and
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 #ifdefPy_DEBUG and #endif. Enable assert(...) and _PyObject_ASSERT(...) assertions: don’t set the NDEBUG macro (see also the
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 (
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
and the
configure option.
Changed in version 3.8: Release builds are now ABI compatible with debug builds: defining the Py_DEBUG macro no longer implies the Py_TRACE_REFS macro (see the
option). However, debug builds still expose more symbols than release builds and code built against a debug build is not necessarily compatible with a release build.
3.3.9. Debug options
--with-pydebug
: 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
function.
Add
environment variable.
The
environment variable can be used to dump objects and reference counts still alive at Python exit.
are not traced.
Added in version 3.8.
Changed in version 3.13: This build is now ABI compatible with release build and
.
--with-assertions
Build with C assertions enabled (default is no): assert(...); and _PyObject_ASSERT(...);.
If set, the NDEBUG macro is not defined in the
compiler variable.
See also the
option (
) 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). To improve ASan detection capabilities you may also want to combine this with
to disable the specialized small-object allocator whose allocations are not tracked by ASan.
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.
--enable-static-libpython-for-interpreter
Do not link the Python interpreter binary (python3) against the shared Python library; instead, statically link the interpreter against libpython as if --enable-shared had not been used, but continue to build the shared libpython (for use by other programs).
This option does nothing if --enable-shared is not used.
The default (when -enable-shared is used) is to link the Python interpreter against the built shared library.
Added in version 3.15.
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-readline=readline|editline
Designate a backend library for the
module.
readline: Use readline as the backend.
editline: Use editline as the backend.
Added in version 3.10.
--without-readline
Don’t build the
module (built by default).
Don’t define the HAVE_LIBREADLINE macro.
Added in version 3.10.
--with-curses=ncursesw|ncurses|curses
Designate a backend library for the
and
modules.
ncursesw: Use the wide-character libncursesw (and libpanelw), found via pkg-config.
ncurses: Use libncurses (and libpanel), found via pkg-config.
curses: Use the system’s native libcurses (and libpanel), such as on NetBSD or Solaris. It is built with wide-character support when the library provides it.
Without this option (or with --with-curses=auto, the default), Python tries ncursesw and then ncurses; the native curses is used only when requested explicitly.
Added in version 3.16.0a0 (unreleased).
--without-curses
Don’t build the
and
modules, even when a curses library is present (built by default when one is found).
Added in version 3.16.0a0 (unreleased).
--with-zlib=zlib|zlib-ng|zlib-rs
Designate the zlib implementation to build the
module against.
zlib: Use the system zlib library, found via pkg-config or as libz.
zlib-ng: Same detection as zlib, but fail unless the detected library is
.
zlib-rs: Use
, found via pkg-config as libz_rs.
Without this option (or with --with-zlib=auto, the default), the system zlib is used when found; configure only fails when an implementation was requested explicitly but cannot be found.
Added in version 3.16.0a0 (unreleased).
--without-zlib
Don’t build the
module, even when a zlib library is present (built by default when one is found).
Added in version 3.16.0a0 (unreleased).
--with-bzip2=bzip2|bzip2-rs
Designate the bzip2 implementation to build the
module against.
bzip2: Use the system bzip2 library, found via pkg-config or as libbz2.
bzip2-rs: Use
, found via pkg-config as libbz2_rs.
Without this option (or with --with-bzip2=auto, the default), the system bzip2 is used when found; configure only fails when an implementation was requested explicitly but cannot be found.
Added in version 3.16.0a0 (unreleased).
--without-bzip2
Don’t build the
module, even when a bzip2 library is present (built by default when one is found).
Added in version 3.16.0a0 (unreleased).
--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
and pkg-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
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.
--disable-safety
Disable compiler options that are
for security reasons with no performance overhead. If this option is not enabled, CPython will be built based on safety compiler options with no slow down. When this option is enabled, CPython will not be built with the compiler options listed below.
The following compiler options are disabled with --disable-safety:
: Enable run-time checks for stack-based buffer overflows.
: Enable warnings about trampolines that require executable stacks.
Added in version 3.14.
--enable-slower-safety
Enable compiler options that are
for security reasons which require overhead. If this option is not enabled, CPython will not be built based on safety compiler options which performance impact. When this option is enabled, CPython will be built with the compiler options listed below.
The following compiler options are enabled with --enable-slower-safety:
: Fortify sources with compile- and run-time checks for unsafe libc usage and buffer overflows.
Added in version 3.14.
3.3.13. macOS Options
See
.
--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
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
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
.
--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).
An iOS build configured without --enable-framework produces a static libpython, for embedding directly in an app binary. Such a build cannot load extension modules at runtime, and so does not support binary wheels; it requires MODULE_BUILDTYPE=static and
, and rejects
. See
for the full list of limitations.
Added in version 3.16: iOS builds may be configured without a framework.
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-aarch64ac_cv_buggy_getaddrinfo=noac_cv_file__dev_ptmx=yesac_cv_file__dev_ptc=noHOSTRUNNER
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 by configure);
pyconfig.h (created by configure);
Modules/Setup: C extensions built by the Makefile using Module/makesetup shell script;
3.4.2. Main build steps
C files (.c) are built as object files (.o).
A static libpython library (.a) is created from objects files.
python.o and the static libpython library are linked into the final python program.
C extensions are built by the Makefile (see Modules/Setup).
3.4.3. Main Makefile targets
3.4.3.1. make
For the most part, when rebuilding after editing some code or refreshing your checkout from upstream, all you need to do is execute make, which (per Make’s semantics) builds the default target, the first one defined in the Makefile. By tradition (including in the CPython project) this is usually the all target. The configure script expands an autoconf variable, @DEF_MAKE_ALL_RULE@ to describe precisely which targets makeall will build. The three choices are:
profile-opt (configured with --enable-optimizations)
build_wasm (chosen if the host platform matches wasm32-wasi* or wasm32-emscripten)
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, makeclean&&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
option to make this the default target of the make command (makeall or just make).
3.4.3.4. make clean
Remove built files.
3.4.3.5. make distclean
In addition to the work done by makeclean, remove files created by the configure script. configure will have to be run before building again.
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 without GUI tests. 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 ci
This is similar to maketest, but uses the -ugui to also run GUI tests.
Added in version 3.14.
3.4.3.9. make buildbottest
This is similar to maketest, but uses the --slow-ci option and default timeout of 20 minutes, instead of --fast-ci option.
3.4.3.10. make regen-all
Regenerate (almost) all generated files. These include (but are not limited to) bytecode cases, and parser generator file. makeregen-stdlib-module-names and autoconf must be run separately for the remaining
.
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:
>>> importsys>>> 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
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
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
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
and
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
is used for building the interpreter and stdlib C extensions. Use it when a compiler flag should not be part of
once Python is installed (
).
In particular,
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
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
command line when building PYC files in makeinstall. Default: -j0.
Added in version 3.12.
Extra C compiler flags.
CONFIGURE_CFLAGS
Value of
variable passed to the ./configure script.
Added in version 3.2.
CONFIGURE_CFLAGS_NODIST
Value of
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.
CFLAGS_CEVAL
Flags used to compile Python/ceval.c.
Added in version 3.14.5.
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
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
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
variable passed to the ./configure script.
Avoid assigning
,
, 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
. Use it when a linker flag should not be part of
once Python is installed (
).
In particular,
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
would take precedence over user- and package-supplied -L flags.
CONFIGURE_LDFLAGS_NODIST
Value of
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
and
need to contain the shell’s value to be able to build extension modules using the directories specified in the environment variables.
Please consider using EXE_LDFLAGS if the supplied linker flags are executable specific, e.g. GCC’s -pie flag.
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.
EXE_LDFLAGS
Linker flags used for building executable targets such as the interpreter. If supplied,
will be used in replacement of
.
Added in version 3.15.
CONFIGURE_EXE_LDFLAGS
Value of
variable passed to the ./configure script.
Added in version 3.15.
PY_CORE_EXE_LDFLAGS
Linker flags used for building the interpreter and executable targets.
Default: $(PY_CORE_LDFLAGS)
Added in version 3.15.
Footnotes