Tree [dbb703] legacy-trunk /

File Date Author Commit
 Demo 2001-12-27 Guido van Rossum Guido van Rossum [455407] Updated -- all Demo subdirectories are once aga...
 Doc 2002-01-17 Fred Drake Fred Drake [0eff96] Updated GNU info dir segment from Milan Zamazal.
 Grammar 2001-10-15 Guido van Rossum Guido van Rossum [56141b] Very subtle syntax change: in a list comprehens...
 Include 2002-01-17 Martin v. Löwis Martin v. Löwis [d60350] Patch #477752: Drop old-style getargs from curses.
 Lib 2002-01-18 Thomas Heller Thomas Heller [dbb703] SWIGing a source file <name>.i silently overwri...
 Mac 2002-01-18 Jack Jansen Jack Jansen [7233b8] Added as_pathname() method to FSRef objects.
 Misc 2002-01-12 Martin v. Löwis Martin v. Löwis [630293] Patch #414775: Add --skip-build option to bdist...
 Modules 2002-01-17 Martin v. Löwis Martin v. Löwis [40631a] Patch #477750: Use METH_ constants in Modules.
 Objects 2002-01-16 Martin v. Löwis Martin v. Löwis [30a817] Updated patch #487906: Revise inline docs.
 PC 2002-01-12 Martin v. Löwis Martin v. Löwis [c64fc5] Include <unistd.h> in Python.h. Fixes #500924.
 PCbuild 2002-01-15 Tim Peters Tim Peters [dccbd7] Update master Windows buildno list for 2.1.2final.
 Parser 2002-01-12 Martin v. Löwis Martin v. Löwis [c64fc5] Include <unistd.h> in Python.h. Fixes #500924.
 Python 2002-01-15 Guido van Rossum Guido van Rossum [5d2bfb] A tentative fix for SF bug #503837 (Roeland Ren...
 RISCOS 2001-12-15 Tim Peters Tim Peters [f54662] SF patch 493739 2 Bugfixes for 2.2c1 (RISC OS s...
 Tools 2002-01-01 Jack Jansen Jack Jansen [8dfbfb] Added some support for Uicode arguments. Still ...
 .cvsignore 2001-08-09 Thomas Wouters Thomas Wouters [c4b31b] Michael Hudson correctly pointed out we should ...
 .hgtags 2001-09-08 cvs2svn cvs2svn [08796a] This commit was manufactured by cvs2svn to crea...
 LICENSE 2001-07-17 Guido van Rossum Guido van Rossum [cfb57d] A new attempt at rationalizing the "history of ... 2002-01-17 Martin v. Löwis Martin v. Löwis [74246a] Use BLDLIBRARY to build extension modules. Fixe...
 PLAN.txt 2001-11-01 Guido van Rossum Guido van Rossum [def2a1] The GC issues with __del__ are now dealt with.
 README 2002-01-04 Jack Jansen Jack Jansen [586188] Rephrased the OSX stack limit problem, after a ...
 acconfig.h 2002-01-01 Martin v. Löwis Martin v. Löwis [67da11] Patch #497098: build support for GNU/Hurd.
 configure 2002-01-01 Martin v. Löwis Martin v. Löwis [67da11] Patch #497098: build support for GNU/Hurd. 2002-01-01 Martin v. Löwis Martin v. Löwis [67da11] Patch #497098: build support for GNU/Hurd.
 install-sh 2001-02-10 Neil Schemenauer Neil Schemenauer [9a9579] Update install-sh using version from automake 1... 2002-01-01 Martin v. Löwis Martin v. Löwis [67da11] Patch #497098: build support for GNU/Hurd. 2002-01-16 Michael W. Hudson Michael W. Hudson [9d5adf] Apply a variant of patch

Read Me

This is Python version 2.2

Copyright (c) 2001 Python Software Foundation.
All rights reserved.

Copyright (c) 2000
All rights reserved.

Copyright (c) 1995-2001 Corporation for National Research Initiatives.
All rights reserved.

Copyright (c) 1991-1995 Stichting Mathematisch Centrum.
All rights reserved.

License information

See the file "LICENSE" for information on the history of this
software, terms & conditions for usage, and a DISCLAIMER OF ALL

This Python distribution contains no GNU General Public Licensed
(GPLed) code so it may be used in proprietary projects just like prior
Python distributions.  There are interfaces to some GNU code but these
are entirely optional.

All trademarks referenced herein are property of their respective

What's new in this release?

See the file "Misc/NEWS".

If you don't read instructions

Congratulations on getting this far. :-)

To start building right away (on UNIX): type "./configure" in the
current directory and when it finishes, type "make".  The section
`Build Instructions' below is still recommended reading, especially
the part on customizing Modules/Setup.

What is Python anyway?

Python is an interpreted object-oriented programming language suitable
(amongst other uses) for distributed application development,
scripting, numeric computing and system testing.  Python is often
compared to Tcl, Perl, Java, JavaScript, Visual Basic or Scheme.  To
find out more about what Python can do for you, point your browser to

How do I learn Python?

The official tutorial is still a good place to start; see for online and downloadable versions, as
well as a list of other introductions, and reference documentation.

There's a quickly growing set of books on Python.  See for a list.


All documentation is provided online in a variety of formats.  In
order of importance for new users: Tutorial, Library Reference,
Language Reference, Extending & Embedding, and the Python/C API.  The
Library Reference is especially of immense value since much of
Python's power is described there, including the built-in data types
and functions!

All documentation is also available online at the Python web site
(, see below).  It is available online for
occasional reference, or can be downloaded in many formats for faster
access.  The documentation is available in HTML, PostScript, PDF, and
LaTeX formats; the LaTeX version is primarily for documentation
authors, translators, and people with special formatting requirements.

The best documentation for the new (in Python 2.2) type/class unification
features is Guido's tutorial introduction, at

Web sites

New Python releases and related technologies are published at  Come visit us!

There's also a Python community web site at

Newsgroups and Mailing Lists

Read comp.lang.python, a high-volume discussion newsgroup about
Python, or comp.lang.python.announce, a low-volume moderated newsgroup
for Python-related announcements.  These are also accessible as
mailing lists: see for an
overview of the many Python-related mailing lists.

Archives are accessible via Usenet News: see  The mailing lists are also archived, see for details.

Bug reports

To report or search for bugs, please use the Python Bug
Tracker at

Patches and contributions

To submit a patch or other contribution, please use the Python Patch
Manager at  Guidelines
for patch submission may be found at

If you have a proposal to change Python, it's best to submit a Python
Enhancement Proposal (PEP) first.  All current PEPs, as well as
guidelines for submitting a new PEP, are list at


For help, if you can't find it in the manuals or on the web site, it's
best to post to the comp.lang.python or the Python mailing list (see
above).  If you specifically don't want to involve the newsgroup or
mailing list, send questions to (a group of volunteers
who answer questions as they can).  The newsgroup is the most
efficient way to ask public questions.

Build instructions

Before you can build Python, you must first configure it.  Fortunately,
the configuration and build process has been streamlined for most Unix
installations, so all you have to do is type a few commands,
optionally edit one file, and sit back.  There are some platforms
where things are not quite as smooth; see the platform specific notes
below.  If you want to build for multiple platforms sharing the same
source tree, see the section on VPATH below.

Start by running the script "./configure", which determines your system
configuration and creates the Makefile.  (It takes a minute or two --
please be patient!)  You may want to pass options to the configure
script or edit the Modules/Setup file after running configure -- see the
section below on configuration options and variables.  When it's done,
you are ready to run make.

To build Python, you normally type "make" in the toplevel directory.  If
you have changed the configuration or have modified Modules/Setup, the
Makefile may have to be rebuilt.  In this case you may have to run make
again to correctly build your desired target.  The interpreter
executable is built in the top level directory.

Once you have built a Python interpreter, see the subsections below on
testing, configuring additional modules, and installation.  If you run
into trouble, see the next section.  Editing the Modules/Setup file
after running make is supported; just run "make" again after making
the desired changes.


See also the platform specific notes in the next section.

If you run into other trouble, see section 3 of the FAQ
( or for hints on what can go wrong,
and how to fix it.

If you rerun the configure script with different options, remove all
object files by running "make clean" before rebuilding.  Believe it or
not, "make clean" sometimes helps to clean up other inexplicable
problems as well.  Try it before sending in a bug report!

If the configure script fails or doesn't seem to find things that
should be there, inspect the config.log file.  When you fix a
configure problem, be sure to remove config.cache!

If you get a warning for every file about the -Olimit option being no
longer supported, you can ignore it.  There's no foolproof way to know
whether this option is needed; all we can do is test whether it is
accepted without error.  On some systems, e.g. older SGI compilers, it
is essential for performance (specifically when compiling ceval.c,
which has more basic blocks than the default limit of 1000).  If the
warning bothers you, edit the Makefile to remove "-Olimit 1500" from
the OPT variable.

If you get failures in test_long, or sys.maxint gets set to -1, you
are probably experiencing compiler bugs, usually related to
optimization.  This is a common problem with some versions of gcc and
egcs, and some vendor-supplied compilers, which can sometimes be
worked around by turning off optimization.  Consider switching to
stable versions (gcc, egcs 1.1.2, or contact your vendor.)

From Python 2.0 onward, all Python C code is ANSI C.  Compiling using
old K&R-C-only compilers is no longer possible.  ANSI C compilers are
available for all modern systems, either in the form of updated
compilers from the vendor, or one of the free compilers (gcc, egcs).

Platform specific notes

(Some of these may no longer apply.  If you find you can build Python
on these platforms without the special directions mentioned here,
submit a documentation bug report to SourceForge (see Bug Reports
above) so we can remove them!)

64-bit platforms: The modules audioop, imageop and rgbimg don't work.
	Don't try to enable them in the Modules/Setup file.  They
	contain code that is quite wordsize sensitive.  (If you have a
	fix, let us know!)

Solaris: When using Sun's C compiler with threads, at least on Solaris
	2.5.1, you need to add the "-mt" compiler option (the simplest
	way is probably to specify the compiler with this option as
	the "CC" environment variable when running the configure

Linux:  A problem with threads and fork() was tracked down to a bug in
	the pthreads code in glibc version 2.0.5; glibc version 2.0.7
	solves the problem.  This causes the popen2 test to fail;
	problem and solution reported by Pablo Bleyer.

	Under Linux systems using GNU libc 2 (aka libc6), the crypt
	module now needs the -lcrypt option.  Uncomment this flag in
	Modules/Setup, or comment out the crypt module in the same
	file. Most modern Linux systems use glibc2.

FreeBSD 3.x and probably platforms with NCurses that use libmytinfo or
	similar: When using cursesmodule, the linking is not done in
	the correct order with the defaults.  Remove "-ltermcap" from
	the readline entry in Setup, and use as curses entry: "curses
	cursesmodule.c -lmytinfo -lncurses -ltermcap" - "mytinfo" (so
	called on FreeBSD) should be the name of the auxiliary library
	required on your platform.  Normally, it would be linked
	automatically, but not necessarily in the correct order.

BSDI:	BSDI versions before 4.1 have known problems with threads,
	which can cause strange errors in a number of modules (for
	instance, the 'test_signal' test script will hang forever.)
	Turning off threads (with --with-threads=no) or upgrading to
	BSDI 4.1 solves this problem.

DEC Unix: Run configure with --with-dec-threads, or with
	--with-threads=no if no threads are desired (threads are on by
	default).  When using GCC, it is possible to get an internal
	compiler error if optimization is used.  This was reported for
	GCC on selectmodule.c.  Manually compile the affected
	file without optimization to solve the problem.

DEC Ultrix: compile with GCC to avoid bugs in the native compiler,
	and pass SHELL=/bin/sh5 to Make when installing.

AIX:	A complete overhaul of the shared library support is now in
	place.  See Misc/AIX-NOTES for some notes on how it's done.
	(The optimizer bug reported at this place in previous releases
	has been worked around by a minimal code change.) If you get
	errors about ptread_* functions, during compile or during
	testing, try setting CC to a thread-safe (reentrant) compiler,
	like "cc_r".  For full C++ module support, set CC="xlC_r" (or
	CC="xlC" without thread support).

HP-UX:	Please read the file Misc/HPUX-NOTES for shared libraries.
	When using threading, you may have to add -D_REENTRANT to the
	OPT variable in the top-level Makefile; reported by Pat Knight,
	this seems to make a difference (at least for HP-UX 10.20)
	even though config.h defines it.

Minix:  When using ack, use "CC=cc AR=aal RANLIB=: ./configure"!

SCO:	The following apply to SCO 3 only; Python builds out of the box
	on SCO 5 (or so we've heard).

	1) Everything works much better if you add -U__STDC__ to the
	defs.  This is because all the SCO header files are broken.
	Anything that isn't mentioned in the C standard is
	conditionally excluded when __STDC__ is defined.

	2) Due to the U.S. export restrictions, SCO broke the crypt
	stuff out into a separate library, libcrypt_i.a so the LIBS
	needed be set to:

		LIBS=' -lsocket -lcrypt_i'

UnixWare: There are known bugs in the math library of the system, as well as
        problems in the handling of threads (calling fork in one
        thread may interrupt system calls in others). Therefore, test_math and
        tests involving threads will fail until those problems are fixed.

SunOS 4.x: When using the SunPro C compiler, you may want to use the
	'-Xa' option instead of '-Xc', to enable some needed non-ANSI

NeXT:   Not supported anymore. Start with the MacOSX/Darwin code if you
	want to revive it.

QNX:	Chris Herborth ( writes:
	configure works best if you use GNU bash; a port is available on in /usr/free.  I used the following process to build,
	test and install Python 1.5.x under QNX:

	1) CONFIG_SHELL=/usr/local/bin/bash CC=cc RANLIB=: \
	    ./configure --verbose --without-gcc --with-libm=""

	2) edit Modules/Setup to activate everything that makes sense for
	   your system... tested here at QNX with the following modules:

		array, audioop, binascii, cPickle, cStringIO, cmath,
		crypt, curses, errno, fcntl, gdbm, grp, imageop,
		_locale, math, md5, new, operator, parser, pcre,
		posix, pwd, readline, regex, reop, rgbimg, rotor,
		select, signal, socket, soundex, strop, struct,
		syslog, termios, time, timing, zlib, audioop, imageop, rgbimg

	3) make SHELL=/usr/local/bin/bash

	   or, if you feel the need for speed:

	   make SHELL=/usr/local/bin/bash OPT="-5 -Oil+nrt"

	4) make SHELL=/usr/local/bin/bash test

	   Using GNU readline 2.2 seems to behave strangely, but I
	   think that's a problem with my readline 2.2 port.  :-\

	5) make SHELL=/usr/local/bin/bash install

	If you get SIGSEGVs while running Python (I haven't yet, but
	I've only run small programs and the test cases), you're
	probably running out of stack; the default 32k could be a
	little tight.  To increase the stack size, edit the Makefile
	to read: LDFLAGS = -N 48k

BeOS:	Chris Herborth ( writes:
	See BeOS/README for notes about compiling/installing Python on
	BeOS R3 or later.  Note that only the PowerPC platform is
	supported for R3; both PowerPC and x86 are supported for R4.

Cray T3E: Konrad Hinsen writes:
	1) Don't use gcc. It compiles Python/graminit.c into something
	   that the Cray assembler doesn't like. Cray's cc seems to work
	2) Comment out modules md5 (won't compile) and audioop (will
	   crash the interpreter during the test suite).
	If you run the test suite, two tests will fail (rotate and
	binascii), but these are not the modules you'd expect to need
	on a Cray.

SGI:	SGI's standard "make" utility (/bin/make or /usr/bin/make)
	does not check whether a command actually changed the file it
	is supposed to build.  This means that whenever you say "make"
	it will redo the link step.  The remedy is to use SGI's much
	smarter "smake" utility (/usr/sbin/smake), or GNU make.  If
	you set the first line of the Makefile to #!/usr/sbin/smake
	smake will be invoked by make (likewise for GNU make).

	WARNING: There are bugs in the optimizer of some versions of
	SGI's compilers that can cause bus errors or other strange
	behavior, especially on numerical operations.  To avoid this,
	try building with "make OPT=".

OS/2:   If you are running Warp3 or Warp4 and have IBM's VisualAge C/C++
        compiler installed, just change into the pc\os2vacpp directory
        and type NMAKE.  Threading and sockets are supported by default
        in the resulting binaries of PYTHON15.DLL and PYTHON.EXE.

Monterey (64-bit AIX): The current Monterey C compiler (Visual Age)
        uses the OBJECT_MODE={32|64} environment variable to set the
        compilation mode to either 32-bit or 64-bit (32-bit mode is
        the default).  Presumably you want 64-bit compilation mode for
        this 64-bit OS.  As a result you must first set OBJECT_MODE=64
        in your environment before configuring (./configure) or
        building (make) Python on Monterey.

Reliant UNIX: The thread support does not compile on Reliant UNIX, and
        there is a (minor) problem in the configure script for that
        platform as well.  This should be resolved in time for a
        future release.

Mac OS X 10: One of the regular expression tests fails with a segmentation 
        violation (SIGSEGV) due to the small stack size used by default,
        if you give the command "limit stacksize 2048" before "make test"
        it should work.

        On naked Darwin you may want to add the configure option
        "--disable-toolbox-glue" to disable the glue code for the Carbon
        interface modules. The modules themselves are currently only built
        if you add the --enable-framework option, see below.

        On a clean OSX /usr/local does not exist. Do a
        "sudo mkdir -m 775 /usr/local"
        before you do a make install. Alternatively, do "sudo make install"
        which installs everything as superuser.

        You may want to try the configure option "--enable-framework"
        which installs Python as a framework. The location can be set
        as argument to the --enable-framework option (default
        /Library/Frameworks). You may also want to check out ./Mac/OSX
        for building a You may also want to manually
        install a symlink in /usr/local/bin/python to the executable
        deep down in the framework.

Cygwin: With recent (relative to the time of writing, 2001-12-19)
        Cygwin installations, there are problems with the interaction
        of dynamic linking and fork().  This manifests itself in build
        failures during the execution of

        There are two workarounds that both enable Python (albeit
        without threading support) to build and pass all tests on
        NT/2000 (and most likely XP as well, though reports of testing
        on XP would be appreciated).

        The workarounds:

        (a) the band-aid fix is to link the _socket module statically
        rather than dynamically (which is the default).

        To do this, run "./configure --with-threads=no" including any
        other options you need (--prefix, etc.).  Then in Modules/Setup
         uncomment the lines:

        #_socket socketmodule.c \
        #	-DUSE_SSL -I$(SSL)/include -I$(SSL)/include/openssl \
        #	-L$(SSL)/lib -lssl -lcrypto

        and remove "local/" from the SSL variable.  Finally, just run

        (b) The "proper" fix is to rebase the Cygwin DLLs to prevent
        base address conflicts.  Details on how to do this can be
        found in the following mail:


        It is hoped that a version of this solution will be
        incorporated into the Cygwin distribution fairly soon.

        Two additional problems:

        (1) Threading support should still be disabled due to a known
        bug in Cygwin pthreads that causes test_threadedtempfile to

        (2) The _curses module does not build.  This is a known
        Cygwin ncurses problem that should be resolved the next time
        that this package is released.

        On older versions of Cygwin, test_poll may hang and test_strftime
        may fail.

        The situation on 9X/Me is not accurately known at present.
        Some time ago, there were reports that the following
        regression tests failed:

            test_select (hang)

        Due to the test_select hang on 9X/Me, one should run the
        regression test using the following:

            make TESTOPTS='-l -x test_select' test

        News regarding these platforms with more recent Cygwin
        versions would be appreciated!

Configuring threads

As of Python 2.0, threads are enabled by default.  If you wish to
compile without threads, or if your thread support is broken, pass the
--with-threads=no switch to configure.  Unfortunately, on some
platforms, additional compiler and/or linker options are required for
threads to work properly.  Below is a table of those options,
collected by Bill Janssen.  We would love to automate this process
more, but the information below is not enough to write a patch for the file, so manual intervention is required.  If you patch
the file and are confident that the patch works, please
send in the patch.  (Don't bother patching the configure script itself
-- it is regenerated each the file changes.)

Compiler switches for threads

The definition of _REENTRANT should be configured automatically, if
that does not work on your system, or if _REENTRANT is defined
incorrectly, please report that as a bug.

    OS/Compiler/threads                     Switches for use with threads
    (POSIX is draft 10, DCE is draft 4)     compile & link

    SunOS 5.{1-5}/{gcc,SunPro cc}/solaris   -mt
    SunOS 5.5/{gcc,SunPro cc}/POSIX         (nothing)
    DEC OSF/1 3.x/cc/DCE                    -threads
    Digital UNIX 4.x/cc/DCE                 -threads
    Digital UNIX 4.x/cc/POSIX               -pthread
    AIX 4.1.4/cc_r/d7                       (nothing)
    AIX 4.1.4/cc_r4/DCE                     (nothing)
    IRIX 6.2/cc/POSIX                       (nothing)

Linker (ld) libraries and flags for threads

    OS/threads                          Libraries/switches for use with threads

    SunOS 5.{1-5}/solaris               -lthread
    SunOS 5.5/POSIX                     -lpthread
    DEC OSF/1 3.x/DCE                   -lpthreads -lmach -lc_r -lc
    Digital UNIX 4.x/DCE                -lpthreads -lpthread -lmach -lexc -lc
    Digital UNIX 4.x/POSIX              -lpthread -lmach -lexc -lc
    AIX 4.1.4/{draft7,DCE}              (nothing)
    IRIX 6.2/POSIX                      -lpthread

Configuring additional built-in modules

Starting with Python 2.1, the script at the top of the source
distribution attempts to detect which modules can be built and
automatically compiles them.  Autodetection doesn't always work, so
you can customize the configuration by editing the Modules/Setup file.
This file is initially copied from Setup.dist by the configure script;
if it does not exist yet, create it by copying Modules/Setup.dist
yourself (configure will never overwrite it).  Never edit Setup.dist
-- always edit Setup or Setup.local (see below).  Read the comments in
the file for information on what kind of edits are allowed.  When you
have edited Setup in the Modules directory, the interpreter will
automatically be rebuilt the next time you run make (in the toplevel

Many useful modules can be built on any Unix system, but some optional
modules can't be reliably autodetected.  Often the quickest way to
determine whether a particular module works or not is to see if it
will build: enable it in Setup, then if you get compilation or link
errors, disable it -- you're either missing support or need to adjust
the compilation and linking parameters for that module.

On SGI IRIX, there are modules that interface to many SGI specific
system libraries, e.g. the GL library and the audio hardware.  These
modules will not be built by the script.

In addition to the file Setup, you can also edit the file Setup.local.
(the makesetup script processes both).  You may find it more
convenient to edit Setup.local and leave Setup alone.  Then, when
installing a new Python version, you can copy your old Setup.local

Setting the optimization/debugging options

If you want or need to change the optimization/debugging options for
the C compiler, assign to the OPT variable on the toplevel make
command; e.g. "make OPT=-g" will build a debugging version of Python
on most platforms.  The default is OPT=-O; a value for OPT in the
environment when the configure script is run overrides this default
(likewise for CC; and the initial value for LIBS is used as the base
set of libraries to link with).

When compiling with GCC, the default value of OPT will also include
the -Wall and -Wstrict-prototypes options.

Additional debugging code to help debug memory management problems can
be enabled by using the --with-pydebug option to the configure script.


If you want C profiling turned on, the easiest way is to run configure
with the CC environment variable to the necessary compiler
invocation.  For example, on Linux, this works for profiling using

    CC="gcc -pg" ./configure

Note that on Linux, gprof apparently does not work for shared
libraries.  The Makefile/Setup mechanism can be used to compile and
link most extension module statically.


To test the interpreter, type "make test" in the top-level directory.
This runs the test set twice (once with no compiled files, once with
the compiled files left by the previous test run).  The test set
produces some output.  You can generally ignore the messages about
skipped tests due to optional features which can't be imported.  (If
you want to test those modules, edit Modules/Setup to configure them.)
If a message is printed about a failed test or a traceback or core
dump is produced, something is wrong.  On some Linux systems (those
that are not yet using glibc 6), test_strftime fails due to a
non-standard implementation of strftime() in the C library. Please
ignore this, or upgrade to glibc version 6.

IMPORTANT: If the tests fail and you decide to mail a bug report,
*don't* include the output of "make test".  It is useless.  Run the
failing test manually, as follows:

	python ../Lib/test/

(substituting the top of the source tree for .. if you built in a
different directory).  This runs the test in verbose mode.


To install the Python binary, library modules, shared library modules
(see below), include files, configuration files, and the manual page,
just type

	make install

This will install all platform-independent files in subdirectories of
the directory given with the --prefix option to configure or to the
`prefix' Make variable (default /usr/local).  All binary and other
platform-specific files will be installed in subdirectories if the
directory given by --exec-prefix or the `exec_prefix' Make variable
(defaults to the --prefix directory) is given.

All subdirectories created will have Python's version number in their
name, e.g. the library modules are installed in
"/usr/local/lib/python<version>/" by default, where <version> is the
<major>.<minor> release number (e.g. "2.1").  The Python binary is
installed as "python<version>" and a hard link named "python" is
created.  The only file not installed with a version number in its
name is the manual page, installed as "/usr/local/man/man1/python.1"
by default.

If you have a previous installation of Python that you don't
want to replace yet, use

	make altinstall

This installs the same set of files as "make install" except it
doesn't create the hard link to "python<version>" named "python" and
it doesn't install the manual page at all.

Alpha/beta revision levels are stripped from the executable and
library filenames during installation. For example, Python2.1a2 will
install as python2.1, overwriting the previous python2.1. To avoid
this, you could set the Makefile VERSION variable manually
(e.g. VERSION=2.1a2) before running "make install" or "make altinstall".

The only thing you may have to install manually is the Python mode for
Emacs found in Misc/python-mode.el.  (But then again, more recent
versions of Emacs may already have it.)  Follow the instructions that
came with Emacs for installation of site-specific files.

On Mac OS X, if you have configured Python with --enable-framework, you
should use "make frameworkinstall" to do the installation. Note that this
installs the Python executable in a place that is not normally on your
PATH, you may want to set up a symlink in /usr/local/bin.

Configuration options and variables

Some special cases are handled by passing options to the configure

WARNING: if you rerun the configure script with different options, you
must run "make clean" before rebuilding.  Exceptions to this rule:
after changing --prefix or --exec-prefix, all you need to do is remove

--with(out)-gcc: The configure script uses gcc (the GNU C compiler) if
	it finds it.  If you don't want this, or if this compiler is
	installed but broken on your platform, pass the option
	--without-gcc.  You can also pass "CC=cc" (or whatever the
	name of the proper C compiler is) in the environment, but the
	advantage of using --without-gcc is that this option is
	remembered by the config.status script for its --recheck

--prefix, --exec-prefix: If you want to install the binaries and the
	Python library somewhere else than in /usr/local/{bin,lib},
	you can pass the option --prefix=DIRECTORY; the interpreter
	binary will be installed as DIRECTORY/bin/python and the
	library files as DIRECTORY/lib/python/*.  If you pass
	--exec-prefix=DIRECTORY (as well) this overrides the
	installation prefix for architecture-dependent files (like the
	interpreter binary).  Note that --prefix=DIRECTORY also
	affects the default module search path (sys.path), when
	Modules/config.c is compiled.  Passing make the option
	prefix=DIRECTORY (and/or exec_prefix=DIRECTORY) overrides the
	prefix set at configuration time; this may be more convenient
	than re-running the configure script if you change your mind
	about the install prefix.

--with-readline: This option is no longer supported.  To use GNU
	readline, enable module "readline" in the Modules/Setup file.

--with-threads: On most Unix systems, you can now use multiple
	threads, and support for this is enabled by default.  To
	disable this, pass --with-threads=no.  If the library required
	for threads lives in a peculiar place, you can use
	--with-thread=DIRECTORY.  IMPORTANT: run "make clean" after
	changing (either enabling or disabling) this option, or you
	will get link errors!  Note: for DEC Unix use
	--with-dec-threads instead.

--with-sgi-dl: On SGI IRIX 4, dynamic loading of extension modules is
	supported by the "dl" library by Jack Jansen, which is
	ftp'able from
	This is enabled (after you've ftp'ed and compiled the dl
	library) by passing --with-sgi-dl=DIRECTORY where DIRECTORY
	is the absolute pathname of the dl library.  (Don't bother on
	IRIX 5, it already has dynamic linking using SunOS style
	shared libraries.)  Support for this feature is deprecated.

--with-dl-dld: Dynamic loading of modules is rumored to be supported
	on some other systems: VAX (Ultrix), Sun3 (SunOS 3.4), Sequent
	Symmetry (Dynix), and Atari ST.  This is done using a
	combination of the GNU dynamic loading package
	( and an
	emulation of the SGI dl library mentioned above (the emulation
	can be found at  To
	enable this, ftp and compile both libraries, then call
	configure, passing it the option
	the absolute pathname of the dl emulation library and
	DLD_DIRECTORY is the absolute pathname of the GNU dld library.
	(Don't bother on SunOS 4 or 5, they already have dynamic
	linking using shared libraries.)  Support for this feature is

--with-libm, --with-libc: It is possible to specify alternative
	versions for the Math library (default -lm) and the C library
	(default the empty string) using the options
	--with-libm=STRING and --with-libc=STRING, respectively.  For
	example, if your system requires that you pass -lc_s to the C
	compiler to use the shared C library, you can pass
	--with-libc=-lc_s. These libraries are passed after all other
	libraries, the C library last.

--with-libs='libs': Add 'libs' to the LIBS that the python interpreter
	is linked against.

--with-cxx=<compiler>: Some C++ compilers require that main() is
        compiled with the C++ if there is any C++ code in the application.
        Specifically, g++ on a.out systems may require that to support
        construction of global objects. With this option, the main() function
        of Python will be compiled with <compiler>; use that only if you
        plan to use C++ extension modules, and if your compiler requires
        compilation of main() as a C++ program.

--with-pydebug:  Enable additional debugging code to help track down
	memory management problems.  This allows printing a list of all
	live objects when the interpreter terminates.

Building for multiple architectures (using the VPATH feature)

If your file system is shared between multiple architectures, it
usually is not necessary to make copies of the sources for each
architecture you want to support.  If the make program supports the
VPATH feature, you can create an empty build directory for each
architecture, and in each directory run the configure script (on the
appropriate machine with the appropriate options).  This creates the
necessary subdirectories and the Makefiles therein.  The Makefiles
contain a line VPATH=... which points to a directory containing the
actual sources.  (On SGI systems, use "smake -J1" instead of "make" if
you use VPATH -- don't try gnumake.)

For example, the following is all you need to build a minimal Python
in /usr/tmp/python (assuming ~guido/src/python is the toplevel
directory and you want to build in /usr/tmp/python):

	$ mkdir /usr/tmp/python
	$ cd /usr/tmp/python
	$ ~guido/src/python/configure
	$ make

Note that configure copies the original Setup file to the build
directory if it finds no Setup file there.  This means that you can
edit the Setup file for each architecture independently.  For this
reason, subsequent changes to the original Setup file are not tracked
automatically, as they might overwrite local changes.  To force a copy
of a changed original Setup file, delete the target Setup file.  (The
makesetup script supports multiple input files, so if you want to be
fancy you can change the rules to create an empty Setup.local if it
doesn't exist and run it with arguments $(srcdir)/Setup Setup.local;
however this assumes that you only need to add modules.)

Building on non-UNIX systems

For Windows (2000/NT/ME/98/95), assuming you have MS VC++ 6.0, the
project files are in PCbuild, the workspace is pcbuild.dsw.  See
PCbuild\readme.txt for detailed instructions.

For other non-Unix Windows compilers, in particular Windows 3.1 and
for OS/2, enter the directory "PC" and read the file "readme.txt".

For the Mac, a separate source distribution will be made available,
for use with the CodeWarrior compiler.  If you are interested in Mac
development, join the PythonMac Special Interest Group
(, or send email to

Of course, there are also binary distributions available for these
platforms -- see

To port Python to a new non-UNIX system, you will have to fake the
effect of running the configure script manually (for Mac and PC, this
has already been done for you).  A good start is to copy the file to config.h and edit the latter to reflect the actual
configuration of your system.  Most symbols must simply be defined as
1 only if the corresponding feature is present and can be left alone
otherwise; however the *_t type symbols must be defined as some variant
of int if they need to be defined at all.

For all platforms, it's important that the build arrange to define the
preprocessor symbol NDEBUG on the compiler command line in a release
build of Python (else assert() calls remain in the code, hurting
release-build performance).  The Unix, Windows and Mac builds already
do this.

Miscellaneous issues

Emacs mode

There's an excellent Emacs editing mode for Python code; see the file
Misc/python-mode.el.  Originally written by the famous Tim Peters, it
is now maintained by the equally famous Barry Warsaw (it's no
coincidence that they now both work on the same team).  The latest
version, along with various other contributed Python-related Emacs
goodies, is online at  And
if you are planning to edit the Python C code, please pick up the
latest version of CC Mode; it
contains a "python" style used throughout most of the Python C source
files.  (Newer versions of Emacs or XEmacs may already come with the
latest version of python-mode.)

The Tk interface

Tk (the user interface component of John Ousterhout's Tcl language) is
also usable from Python.  Since this requires that you first build and
install Tcl/Tk, the Tk interface is not enabled by default when
building Python from source.  Python supports Tcl/Tk version 8.0 and

See for more info on Tcl/Tk, including
the on-line manual pages.

To enable the Python/Tk interface, once you've built and installed
Tcl/Tk, load the file Modules/Setup into your favorite text editor and
search for the string "_tkinter".  Then follow the instructions found
there.  If you have installed Tcl/Tk or X11 in unusual places, you
will have to edit the first line to fix or add the -I and -L options.
(Also see the general instructions at the top of that file.)

For more Tkinter information, see the Tkinter Resource page:

There are demos in the Demo/tkinter directory, in the subdirectories
guido, matt and www (the matt and guido subdirectories have been
overhauled to use more recent Tkinter coding conventions).

Note that there's a Python module called "Tkinter" (capital T) which
lives in Lib/lib-tk/, and a C module called "_tkinter"
(lower case t and leading underscore) which lives in
Modules/_tkinter.c.  Demos and normal Tk applications import only the
Python Tkinter module -- the latter uses the C _tkinter module
directly.  In order to find the C _tkinter module, it must be compiled
and linked into the Python interpreter -- the _tkinter line in the
Setup file does this.  In order to find the Python Tkinter module,
sys.path must be set correctly -- the TKPATH assignment in the Setup
file takes care of this, but only if you install Python properly
("make install libinstall").  (You can also use dynamic loading for
the C _tkinter module, in which case you must manually fix up sys.path
or set $PYTHONPATH for the Python Tkinter module.)

Distribution structure

Most subdirectories have their own README files.  Most files have

.cvsignore	Additional filename matching patterns for CVS to ignore
BeOS/		Files specific to the BeOS port
Demo/           Demonstration scripts, modules and programs
Doc/		Documentation sources (LaTeX)
Grammar/        Input for the parser generator
Include/        Public header files
LICENSE		Licensing information
Lib/            Python library modules Source from which config.status creates the Makefile.pre
Misc/           Miscellaneous useful files
Modules/        Implementation of most built-in modules
Objects/        Implementation of most built-in object types
PC/             Files specific to PC ports (DOS, Windows, OS/2)
PCbuild/	Build directory for Microsoft Visual C++
Parser/         The parser and tokenizer and their input handling
Python/         The byte-compiler and interpreter
README          The file you're reading now
Tools/          Some useful programs written in Python
acconfig.h      Additional input for the GNU autoheader program     Source from which config.h is created (GNU autoheader output)
configure       Configuration shell script (GNU autoconf output)    Configuration specification (input for GNU autoconf)
install-sh      Shell script used to install files

The following files will (may) be created in the toplevel directory by
the configuration and build processes:

Makefile        Build rules
Makefile.pre    Build rules before running Modules/makesetup
buildno		Keeps track of the build number
config.cache    Cache of configuration variables
config.h        Configuration header
config.log      Log from last configure run
config.status   Status from last run of the configure script
getbuildinfo.o	Object file from Modules/getbuildinfo.c
libpython<version>.a	The library archive
python          The executable interpreter
tags, TAGS      Tags files for vi and Emacs

That's all, folks!

--Guido van Rossum (home page: