This is Python version 2.7.18

=============================

Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011,

2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Python Software Foundation. All

rights reserved.

Copyright (c) 2000 BeOpen.com.

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

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.

What is Python anyway?

----------------------

Python is an interpreted, interactive 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://docs.python.org/ 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://wiki.python.org/moin/PythonBooks 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://docs.python.org/, see below). It is available online for occasional

reference, or can be downloaded in many formats for faster access. The

documentation is downloadable in HTML, PostScript, PDF, LaTeX, and

reStructuredText (2.6+) formats; the LaTeX and reStructuredText versions are

primarily for documentation authors, translators, and people with special

formatting requirements.

If you would like to contribute to the development of Python, relevant

documentation is available at:

http://docs.python.org/devguide/

For information about building Python's documentation, refer to Doc/README.txt.

Web sites

---------

New Python releases and related technologies are published at

http://www.python.org/. Come visit us!

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/community/lists/ for an

overview of these and many other Python-related mailing lists.

Archives are accessible via the Google Groups Usenet archive; see

http://groups.google.com/. The mailing lists are also archived, see

http://www.python.org/community/lists/ for details.

Bug reports

-----------

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

Tracker at http://bugs.python.org/.

Patches and contributions

-------------------------

To submit a patch or other contribution, please use the Python Patch

Manager at http://bugs.python.org/. Guidelines

for patch submission may be found at http://www.python.org/dev/patches/.

If you have a proposal to change Python, you may want to send an email to the

comp.lang.python or python-ideas mailing lists for inital feedback. A Python

Enhancement Proposal (PEP) may be submitted if your idea gains ground. All

current PEPs, as well as guidelines for submitting a new PEP, are listed at

http://www.python.org/dev/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 [email protected] (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.

To get an optimized build of Python, "configure --enable-optimizations" before

you run make. This sets the default make targets up to enable Profile Guided

Optimization (PGO) and may be used to auto-enable Link Time Optimization (LTO)

on some platforms. For more details, see the sections bellow.

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.

Profile Guided Optimization

---------------------------

PGO takes advantage of recent versions of the GCC or Clang compilers.

If ran, "make profile-opt" will do several steps.

First, the entire Python directory is cleaned of temporary files that

may have resulted in a previous compilation.

Then, an instrumented version of the interpreter is built, using suitable

compiler flags for each flavour. Note that this is just an intermediary

step and the binary resulted after this step is not good for real life

workloads, as it has profiling instructions embedded inside.

After this instrumented version of the interpreter is built, the Makefile

will automatically run a training workload. This is necessary in order to

profile the interpreter execution. Note also that any output, both stdout

and stderr, that may appear at this step is suppressed.

Finally, the last step is to rebuild the interpreter, using the information

collected in the previous one. The end result will be a Python binary

that is optimized and suitable for distribution or production installation.

Link Time Optimization

----------------------

Enabled via configure's --with-lto flag. LTO takes advantages of recent

compiler toolchains ability to optimize across the otherwise arbitrary .o file

boundary when building final executables or shared libraries for additional

performance gains.

Troubleshooting

---------------

See also the platform specific notes in the next section.

If you run into other trouble, see the FAQ

(http://www.python.org/doc/faq/) 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.

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

some vendor-supplied compilers, which can sometimes be worked around

by turning off optimization. Consider switching to stable versions

(gcc 2.95.2, gcc 3.x, 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).

If "make install" fails mysteriously during the "compiling the library"

step, make sure that you don't have any of the PYTHONPATH or PYTHONHOME

environment variables set, as they may interfere with the newly built

executable which is compiling the library.

Unsupported systems

-------------------

A number of systems are not supported in Python 2.7 anymore. Some

support code is still present, but will be removed in later versions.

If you still need to use current Python versions on these systems,

please send a message to [email protected] indicating that you

volunteer to support this system. For a more detailed discussion

regarding no-longer-supported and resupporting platforms, as well

as a list of platforms that became or will be unsupported, see PEP 11.

More specifically, the following systems are not supported any

longer:

- SunOS 4

- DYNIX

- dgux

- Minix

- NeXT

- Irix 4 and --with-sgi-dl

- Linux 1

- Systems defining __d6_pthread_create (configure.ac)

- Systems defining PY_PTHREAD_D4, PY_PTHREAD_D6,

or PY_PTHREAD_D7 in thread_pthread.h

- Systems using --with-dl-dld

- Systems using --without-universal-newlines

- MacOS 9

- Systems using --with-wctype-functions

- Win9x, WinME

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!)

Unix platforms: If your vendor still ships (and you still use) Berkeley DB

1.85 you will need to edit Modules/Setup to build the bsddb185

module and add a line to sitecustomize.py which makes it the

default. In Modules/Setup a line like

bsddb185 bsddbmodule.c

should work. (You may need to add -I, -L or -l flags to direct the

compiler and linker to your include files and libraries.)

XXX I think this next bit is out of date:

64-bit platforms: The modules audioop, and imageop 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).

When using GCC on Solaris, beware of binutils 2.13 or GCC

versions built using it. This mistakenly enables the

-zcombreloc option which creates broken shared libraries on

Solaris. binutils 2.12 works, and the binutils maintainers

are aware of the problem. Binutils 2.13.1 only partially

fixed things. It appears that 2.13.2 solves the problem

completely. This problem is known to occur with Solaris 2.7

and 2.8, but may also affect earlier and later versions of the

OS.

When the dynamic loader complains about errors finding shared

libraries, such as

ld.so.1: ./python: fatal: libstdc++.so.5: open failed:

No such file or directory

you need to first make sure that the library is available on

your system. Then, you need to instruct the dynamic loader how

to find it. You can choose any of the following strategies:

1. When compiling Python, set LD_RUN_PATH to the directories

containing missing libraries.

2. When running Python, set LD_LIBRARY_PATH to these directories.

3. Use crle(8) to extend the search path of the loader.

4. Modify the installed GCC specs file, adding -R options into the

*link: section.

The complex object fails to compile on Solaris 10 with gcc 3.4 (at

least up to 3.4.3). To work around it, define Py_HUGE_VAL as

HUGE_VAL(), e.g.:

make CPPFLAGS='-D"Py_HUGE_VAL=HUGE_VAL()" -I. -I$(srcdir)/Include'

./python setup.py CPPFLAGS='-D"Py_HUGE_VAL=HUGE_VAL()"'

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.

Red Hat Linux: Red Hat 9 built Python2.2 in UCS-4 mode and hacked

Tcl to support it. To compile Python2.3 with Tkinter, you will

need to pass --enable-unicode=ucs4 flag to ./configure.

There's an executable /usr/bin/python which is Python

1.5.2 on most older 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 pthread_* 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).

AIX 5.3: To build a 64-bit version with IBM's compiler, I used the

following:

export PATH=/usr/bin:/usr/vacpp/bin

./configure --with-gcc="xlc_r -q64" --with-cxx="xlC_r -q64" \

--disable-ipv6 AR="ar -X64"

make

HP-UX: 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 pyconfig.h defines it. This seems unnecessary when

using HP/UX 11 and later - threading seems to work "out of the

box".

HP-UX ia64: When building on the ia64 (Itanium) platform using HP's

compiler, some experience has shown that the compiler's

optimiser produces a completely broken version of python

(see http://bugs.python.org/814976). To work around this,

edit the Makefile and remove -O from the OPT line.

To build a 64-bit executable on an Itanium 2 system using HP's

compiler, use these environment variables:

CC=cc

CXX=aCC

BASECFLAGS="+DD64"

LDFLAGS="+DD64 -lxnet"

and call configure as:

./configure --without-gcc

then *unset* the environment variables again before running

make. (At least one of these flags causes the build to fail

if it remains set.) You still have to edit the Makefile and

remove -O from the OPT line.

HP PA-RISC 2.0: A recent bug report (http://bugs.python.org/546117)

suggests that the C compiler in this 64-bit system has bugs

in the optimizer that break Python. Compiling without

optimization solves the problems.

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.

QNX: Chris Herborth ([email protected]) 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,

select, signal, socket, soundex, strop, struct,

syslog, termios, time, timing, zlib, audioop, imageop

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: See Misc/BeOS-NOTES 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: Mark Hadfield ([email protected]) writes:

Python can be built satisfactorily on a Cray T3E but based on

my experience with the NIWA T3E (2002-05-22, version 2.2.1)

there are a few bugs and gotchas. For more information see a

thread on comp.lang.python in May 2002 entitled "Building

Python on Cray T3E".

1) Use Cray's cc and not gcc. The latter was reported not to

work by Konrad Hinsen. It may work now, but it may not.

2) To set sys.platform to something sensible, pass the

following environment variable to the configure script:

MACHDEP=unicosmk

2) Run configure with option "--enable-unicode=ucs4".

3) The Cray T3E does not support dynamic linking, so extension

modules have to be built by adding (or uncommenting) lines

in Modules/Setup. The minimum set of modules is

posix, new, _sre, unicodedata

On NIWA's vanilla T3E system the following have also been

included successfully:

_codecs, _locale, _socket, _symtable, _testcapi, _weakref

array, binascii, cmath, cPickle, crypt, cStringIO, dbm

errno, fcntl, grp, math, md5, operator, parser, pcre, pwd

regex, rotor, select, struct, strop, syslog, termios

time, timing, xreadlines

4) Once the python executable and library have been built, make

will execute setup.py, which will attempt to build remaining

extensions and link them dynamically. Each of these attempts

will fail but should not halt the make process. This is

normal.

5) Running "make test" uses a lot of resources and causes

problems on our system. You might want to try running tests

singly or in small groups.

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.

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.

macOS: Building a complete Python installation requires the use of various

additional third-party libraries, depending on your build platform and

configure options. Not all standard library modules are buildable or

useable on all platforms. Refer to the "Install Dependencies" section

section of the "Developer Guide" for current detailed information on

dependencies for macOS:

https://devguide.python.org/setup/#install-dependencies

On macOS, there are additional configure and build options related

to macOS framework and universal builds. Refer to Mac/README.rst.

The tests will crash on both 10.1 and 10.2 with SEGV in

test_re and test_sre due to the small default stack size. If

you set the stack size to 2048 before doing a "make test" the

failure can be avoided. If you're using the tcsh or csh shells,

use "limit stacksize 2048" and for the bash shell (the default

as of macOS 10.3), use "ulimit -s 2048".

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 macOS /usr/local does not exist. Do a

"sudo mkdir -m 775 /usr/local"

before you do a make install. It is probably not a good idea to

do "sudo make install" which installs everything as superuser,

as this may later cause problems when installing distutils-based

additions.

Some people have reported problems building Python after using "fink"

to install additional unix software. Disabling fink (remove all

references to /sw from your .profile or .login) should solve this.

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.

Two additional problems:

(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!

Windows: When executing Python scripts on the command line using file type

associations (i.e. starting "script.py" instead of "python script.py"),

redirects may not work unless you set a specific registry key. See

the Knowledge Base article <http://support.microsoft.com/kb/321788>.

Configuring the bsddb and dbm modules

-------------------------------------

Beginning with Python version 2.3, the PyBsddb package

<http://pybsddb.sf.net/> was adopted into Python as the bsddb package,

exposing a set of package-level functions which provide

backwards-compatible behavior. Only versions 3.3 through 4.4 of

Sleepycat's libraries provide the necessary API, so older versions

aren't supported through this interface. The old bsddb module has

been retained as bsddb185, though it is not built by default. Users

wishing to use it will have to tweak Modules/Setup to build it. The

dbm module will still be built against the Sleepycat libraries if

other preferred alternatives (ndbm, gdbm) are not found.

Building the sqlite3 module

---------------------------

To build the sqlite3 module, you'll need the sqlite3 or libsqlite3

packages installed, including the header files. Many modern operating

systems distribute the headers in a separate package to the library -

often it will be the same name as the main package, but with a -dev or

-devel suffix.

The version of pysqlite2 that's including in Python needs sqlite3 3.0.8

or later. setup.py attempts to check that it can find a correct version.

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

configure.ac file, so manual intervention is required. If you patch

the configure.ac 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 time the configure.ac 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

([email protected])

Digital UNIX 4.x/cc/DCE -threads

([email protected])

Digital UNIX 4.x/cc/POSIX -pthread

([email protected])

AIX 4.1.4/cc_r/d7 (nothing)

([email protected])

AIX 4.1.4/cc_r4/DCE (nothing)

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IRIX 6.2/cc/POSIX (nothing)

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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

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Digital UNIX 4.x/DCE -lpthreads -lpthread -lmach -lexc -lc

([email protected])

Digital UNIX 4.x/POSIX -lpthread -lmach -lexc -lc

([email protected])

AIX 4.1.4/{draft7,DCE} (nothing)

([email protected])

IRIX 6.2/POSIX -lpthread

([email protected])

Building a shared libpython

---------------------------

Starting with Python 2.3, the majority of the interpreter can be built

into a shared library, which can then be used by the interpreter

executable, and by applications embedding Python. To enable this feature,

configure with --enable-shared.

If you enable this feature, the same object files will be used to create

a static library. In particular, the static library will contain object

files using position-independent code (PIC) on platforms where PIC flags

are needed for the shared library.

Configuring additional built-in modules

---------------------------------------

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.

For flags that change binary compatibility, use the EXTRA_CFLAGS

variable.

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 modules statically.

Coverage checking

-----------------

For C coverage checking using gcov, run "make coverage". This will

build a Python binary with profiling activated, and a ".gcno" and

".gcda" file for every source file compiled with that option. With

the built binary, now run the code whose coverage you want to check.

Then, you can see coverage statistics for each individual source file

by running gcov, e.g.

gcov -o Modules zlibmodule

This will create a "zlibmodule.c.gcov" file in the current directory

containing coverage info for that source file.

This works only for source files statically compiled into the

executable; use the Makefile/Setup mechanism to compile and link

extension modules you want to coverage-check 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.

By default, tests are prevented from overusing resources like disk space and

memory. To enable these tests, run "make testall".

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/regrtest.py -v test_whatever

(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.

If DESTDIR is set, it will be taken as the root directory of the

installation, and files will be installed into $(DESTDIR)$(prefix),

$(DESTDIR)$(exec_prefix), etc.

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 want to install multiple versions of Python see the section below

entitled "Installing multiple versions".

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.

Installing multiple versions

----------------------------

On Unix and Mac systems if you intend to install multiple versions of Python

using the same installation prefix (--prefix argument to the configure

script) you must take care that your primary python executable is not

overwritten by the installation of a different version. All files and

directories installed using "make altinstall" contain the major and minor

version and can thus live side-by-side. "make install" also creates

${prefix}/bin/python which refers to ${prefix}/bin/pythonX.Y. If you intend

to install multiple versions using the same prefix you must decide which

version (if any) is your "primary" version. Install that version using

"make install". Install all other versions using "make altinstall".

For example, if you want to install Python 2.5, 2.6 and 3.0 with 2.6 being

the primary version, you would execute "make install" in your 2.6 build

directory and "make altinstall" in the others.

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