# features/pathlib /

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## This is Python version 2.2.1

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

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 holders.

### 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". This creates an executable "./python"; to install in /usr/local, first do "su root" and then "make install".

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 http://www.python.org/.

### How do I learn Python?

The official tutorial is still a good place to start; see http://www.python.org/doc/ 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 http://www.python.org/psa/bookstore/ for a list.

### Documentation

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 (http://www.python.org/doc/, 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

http://www.python.org/2.2/descrintro.html

### Web sites

New Python releases and related technologies are published at http://www.python.org/. Come visit us!

There's also a Python community web site at http://starship.python.net/.

### 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 http://www.python.org/psa/MailingLists.html for an overview of the many Python-related mailing lists.

Archives are accessible via Deja.com Usenet News: see http://www.deja.com/usenet. The mailing lists are also archived, see http://www.python.org/psa/MailingLists.html for details.

### Bug reports

To report or search for bugs, please use the Python Bug Tracker at http://sourceforge.net/bugs/?group_id=5470.

### Patches and contributions

To submit a patch or other contribution, please use the Python Patch Manager at http://sourceforge.net/patch/?group_id=5470. Guidelines for patch submission may be found at http://www.python.org/patches/.

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 http://python.sourceforge.net/peps/.

### Questions

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 help@python.org (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 automated for Unix and Linux installations, so all you usually have to do is type a few commands 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 -- 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, 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 and installation. If you run into trouble, see the next section.

Previous versions of Python used a manual configuration process that involved editing the file Modules/Setup. While this file still exists and manual configuration is still supported, it is rarely needed any more: almost all modules are automatically built as appropriate under guidance of the setup.py script, which is run by Make after the interpreter has been built.

### Troubleshooting

If you run into other trouble, see section 3 of the FAQ (http://www.python.org/cgi-bin/faqw.py or http://www.python.org/doc/FAQ.html) 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 2.7.2.3, 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.
The setup.py script disables them on 64-bit installations. 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 script).
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. The setup.py script takes care of this automatically.

Red Hat Linux: There's an executable /usr/bin/python which is Python
1.5.2 on most Red Hat installations; several key Red Hat tools require this version. Python 2.1.x may be installed as /usr/bin/python2. The Makefile installs Python as /usr/local/bin/python, which may or may not take precedence over /usr/bin/python, depending on how you have set up $PATH. 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 2.7.2.3 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 Sunisms. NeXT: Not supported anymore. Start with the MacOSX/Darwin code if you want to revive it. QNX: Chris Herborth (chrish@qnx.com) writes: configure works best if you use GNU bash; a port is available on ftp.qnx.com 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 (chrish@qnx.com) 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 fine. 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 pcos2vacpp 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 SEGV due to the small stack size used by default, if you do "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 Python.app. 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 setup.py. 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: #SSL=/usr/local/ssl #_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 "make"!

(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:

http://sources.redhat.com/ml/cygwin/2001-12/msg00894.html

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

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

(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_pwd test_select (hang) test_socket

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!

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 configure.in file, so manual intervention is required. If you patch the configure.in 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 configure.in file changes.)

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

(butenhof@zko.dec.com)
(butenhof@zko.dec.com)
(butenhof@zko.dec.com)
AIX 4.1.4/cc_r/d7 (nothing)
(buhrt@iquest.net)
AIX 4.1.4/cc_r4/DCE (nothing)
(buhrt@iquest.net)
IRIX 6.2/cc/POSIX (nothing)
(robertl@cwi.nl)

(butenhof@zko.dec.com)
(butenhof@zko.dec.com)
Digital UNIX 4.x/POSIX -lpthread -lmach -lexc -lc
(butenhof@zko.dec.com)
AIX 4.1.4/{draft7,DCE} (nothing)
(buhrt@iquest.net)
(jph@emilia.engr.sgi.com)

Starting with Python 2.1, the setup.py 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 still customize the configuration by editing the Modules/Setup file; but this should be considered a last resort. The rest of this section only applies if you decide to edit the Modules/Setup file. You also need this to enable static linking of certain modules (which is needed to enable profiling on some systems).

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 directory).

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 setup.py 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 file.

### 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.

### Profiling

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 gprof(1):

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.

### Testing

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 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/test_whatever.py

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

### Installing

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 script.

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 Modules/getpath.o.

--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 option.
--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. GNU
readline is automatically enabled by setup.py when present.
--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.
supported by the "dl" library by Jack Jansen, which is ftp'able from ftp://ftp.cwi.nl/pub/dynload/dl-1.6.tar.Z. 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.
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 (ftp://ftp.cwi.nl/pub/dynload/dl-dld-1.1.tar.Z) and an emulation of the SGI dl library mentioned above (the emulation can be found at ftp://ftp.cwi.nl/pub/dynload/dld-3.2.3.tar.Z). To enable this, ftp and compile both libraries, then call configure, passing it the option --with-dl-dld=DL_DIRECTORY,DLD_DIRECTORY where DL_DIRECTORY is 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 deprecated.
--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
--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 PCbuildreadme.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 (http://www.python.org/sigs/pythonmac-sig/, or send email to pythonmac-sig-request@python.org).

Of course, there are also binary distributions available for these platforms -- see http://www.python.org/.

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 config.h.in 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 http://www.python.org/emacs/python-mode. And if you are planning to edit the Python C code, please pick up the latest version of CC Mode http://www.python.org/emacs/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.)

### Tkinter

The setup.py script automatically configures this when it detects a usable Tcl/Tk installation. This requires Tcl/Tk version 8.0 or higher.

For more Tkinter information, see the Tkinter Resource page: http://www.python.org/topics/tkinter/

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/Tkinter.py, 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 -- only the latter imports the C _tkinter module. In order to find the C _tkinter module, it must be compiled and linked into the Python interpreter -- the setup.py script does this. In order to find the Python Tkinter module, sys.path must be set correctly -- normal installation takes care of this.