1.. highlightlang:: none 2 3.. _install-index: 4 5******************************************** 6 Installing Python Modules (Legacy version) 7******************************************** 8 9:Author: Greg Ward 10 11.. TODO: Fill in XXX comments 12 13.. seealso:: 14 15 :ref:`installing-index` 16 The up to date module installation documentations 17 18.. The audience for this document includes people who don't know anything 19 about Python and aren't about to learn the language just in order to 20 install and maintain it for their users, i.e. system administrators. 21 Thus, I have to be sure to explain the basics at some point: 22 sys.path and PYTHONPATH at least. Should probably give pointers to 23 other docs on "import site", PYTHONSTARTUP, PYTHONHOME, etc. 24 25 Finally, it might be useful to include all the material from my "Care 26 and Feeding of a Python Installation" talk in here somewhere. Yow! 27 28This document describes the Python Distribution Utilities ("Distutils") from the 29end-user's point-of-view, describing how to extend the capabilities of a 30standard Python installation by building and installing third-party Python 31modules and extensions. 32 33 34.. note:: 35 36 This guide only covers the basic tools for building and distributing 37 extensions that are provided as part of this version of Python. Third party 38 tools offer easier to use and more secure alternatives. Refer to the `quick 39 recommendations section <https://packaging.python.org/en/latest/current/>`__ 40 in the Python Packaging User Guide for more information. 41 42 43.. _inst-intro: 44 45 46Introduction 47============ 48 49Although Python's extensive standard library covers many programming needs, 50there often comes a time when you need to add some new functionality to your 51Python installation in the form of third-party modules. This might be necessary 52to support your own programming, or to support an application that you want to 53use and that happens to be written in Python. 54 55In the past, there has been little support for adding third-party modules to an 56existing Python installation. With the introduction of the Python Distribution 57Utilities (Distutils for short) in Python 2.0, this changed. 58 59This document is aimed primarily at the people who need to install third-party 60Python modules: end-users and system administrators who just need to get some 61Python application running, and existing Python programmers who want to add some 62new goodies to their toolbox. You don't need to know Python to read this 63document; there will be some brief forays into using Python's interactive mode 64to explore your installation, but that's it. If you're looking for information 65on how to distribute your own Python modules so that others may use them, see 66the :ref:`distutils-index` manual. :ref:`debug-setup-script` may also be of 67interest. 68 69 70 71.. _inst-trivial-install: 72 73Best case: trivial installation 74------------------------------- 75 76In the best case, someone will have prepared a special version of the module 77distribution you want to install that is targeted specifically at your platform 78and is installed just like any other software on your platform. For example, 79the module developer might make an executable installer available for Windows 80users, an RPM package for users of RPM-based Linux systems (Red Hat, SuSE, 81Mandrake, and many others), a Debian package for users of Debian-based Linux 82systems, and so forth. 83 84In that case, you would download the installer appropriate to your platform and 85do the obvious thing with it: run it if it's an executable installer, ``rpm 86--install`` it if it's an RPM, etc. You don't need to run Python or a setup 87script, you don't need to compile anything---you might not even need to read any 88instructions (although it's always a good idea to do so anyway). 89 90Of course, things will not always be that easy. You might be interested in a 91module distribution that doesn't have an easy-to-use installer for your 92platform. In that case, you'll have to start with the source distribution 93released by the module's author/maintainer. Installing from a source 94distribution is not too hard, as long as the modules are packaged in the 95standard way. The bulk of this document is about building and installing 96modules from standard source distributions. 97 98 99.. _inst-new-standard: 100 101The new standard: Distutils 102--------------------------- 103 104If you download a module source distribution, you can tell pretty quickly if it 105was packaged and distributed in the standard way, i.e. using the Distutils. 106First, the distribution's name and version number will be featured prominently 107in the name of the downloaded archive, e.g. :file:`foo-1.0.tar.gz` or 108:file:`widget-0.9.7.zip`. Next, the archive will unpack into a similarly-named 109directory: :file:`foo-1.0` or :file:`widget-0.9.7`. Additionally, the 110distribution will contain a setup script :file:`setup.py`, and a file named 111:file:`README.txt` or possibly just :file:`README`, which should explain that 112building and installing the module distribution is a simple matter of running 113one command from a terminal:: 114 115 python setup.py install 116 117For Windows, this command should be run from a command prompt window 118(:menuselection:`Start --> Accessories`):: 119 120 setup.py install 121 122If all these things are true, then you already know how to build and install the 123modules you've just downloaded: Run the command above. Unless you need to 124install things in a non-standard way or customize the build process, you don't 125really need this manual. Or rather, the above command is everything you need to 126get out of this manual. 127 128 129.. _inst-standard-install: 130 131Standard Build and Install 132========================== 133 134As described in section :ref:`inst-new-standard`, building and installing a module 135distribution using the Distutils is usually one simple command to run from a 136terminal:: 137 138 python setup.py install 139 140 141.. _inst-platform-variations: 142 143Platform variations 144------------------- 145 146You should always run the setup command from the distribution root directory, 147i.e. the top-level subdirectory that the module source distribution unpacks 148into. For example, if you've just downloaded a module source distribution 149:file:`foo-1.0.tar.gz` onto a Unix system, the normal thing to do is:: 150 151 gunzip -c foo-1.0.tar.gz | tar xf - # unpacks into directory foo-1.0 152 cd foo-1.0 153 python setup.py install 154 155On Windows, you'd probably download :file:`foo-1.0.zip`. If you downloaded the 156archive file to :file:`C:\\Temp`, then it would unpack into 157:file:`C:\\Temp\\foo-1.0`; you can use either an archive manipulator with a 158graphical user interface (such as WinZip) or a command-line tool (such as 159:program:`unzip` or :program:`pkunzip`) to unpack the archive. Then, open a 160command prompt window and run:: 161 162 cd c:\Temp\foo-1.0 163 python setup.py install 164 165 166.. _inst-splitting-up: 167 168Splitting the job up 169-------------------- 170 171Running ``setup.py install`` builds and installs all modules in one run. If you 172prefer to work incrementally---especially useful if you want to customize the 173build process, or if things are going wrong---you can use the setup script to do 174one thing at a time. This is particularly helpful when the build and install 175will be done by different users---for example, you might want to build a module 176distribution and hand it off to a system administrator for installation (or do 177it yourself, with super-user privileges). 178 179For example, you can build everything in one step, and then install everything 180in a second step, by invoking the setup script twice:: 181 182 python setup.py build 183 python setup.py install 184 185If you do this, you will notice that running the :command:`install` command 186first runs the :command:`build` command, which---in this case---quickly notices 187that it has nothing to do, since everything in the :file:`build` directory is 188up-to-date. 189 190You may not need this ability to break things down often if all you do is 191install modules downloaded off the 'net, but it's very handy for more advanced 192tasks. If you get into distributing your own Python modules and extensions, 193you'll run lots of individual Distutils commands on their own. 194 195 196.. _inst-how-build-works: 197 198How building works 199------------------ 200 201As implied above, the :command:`build` command is responsible for putting the 202files to install into a *build directory*. By default, this is :file:`build` 203under the distribution root; if you're excessively concerned with speed, or want 204to keep the source tree pristine, you can change the build directory with the 205:option:`!--build-base` option. For example:: 206 207 python setup.py build --build-base=/path/to/pybuild/foo-1.0 208 209(Or you could do this permanently with a directive in your system or personal 210Distutils configuration file; see section :ref:`inst-config-files`.) Normally, this 211isn't necessary. 212 213The default layout for the build tree is as follows:: 214 215 --- build/ --- lib/ 216 or 217 --- build/ --- lib.<plat>/ 218 temp.<plat>/ 219 220where ``<plat>`` expands to a brief description of the current OS/hardware 221platform and Python version. The first form, with just a :file:`lib` directory, 222is used for "pure module distributions"---that is, module distributions that 223include only pure Python modules. If a module distribution contains any 224extensions (modules written in C/C++), then the second form, with two ``<plat>`` 225directories, is used. In that case, the :file:`temp.{plat}` directory holds 226temporary files generated by the compile/link process that don't actually get 227installed. In either case, the :file:`lib` (or :file:`lib.{plat}`) directory 228contains all Python modules (pure Python and extensions) that will be installed. 229 230In the future, more directories will be added to handle Python scripts, 231documentation, binary executables, and whatever else is needed to handle the job 232of installing Python modules and applications. 233 234 235.. _inst-how-install-works: 236 237How installation works 238---------------------- 239 240After the :command:`build` command runs (whether you run it explicitly, or the 241:command:`install` command does it for you), the work of the :command:`install` 242command is relatively simple: all it has to do is copy everything under 243:file:`build/lib` (or :file:`build/lib.{plat}`) to your chosen installation 244directory. 245 246If you don't choose an installation directory---i.e., if you just run ``setup.py 247install``\ ---then the :command:`install` command installs to the standard 248location for third-party Python modules. This location varies by platform and 249by how you built/installed Python itself. On Unix (and Mac OS X, which is also 250Unix-based), it also depends on whether the module distribution being installed 251is pure Python or contains extensions ("non-pure"): 252 253.. tabularcolumns:: |l|l|l|l| 254 255+-----------------+-----------------------------------------------------+--------------------------------------------------+-------+ 256| Platform | Standard installation location | Default value | Notes | 257+=================+=====================================================+==================================================+=======+ 258| Unix (pure) | :file:`{prefix}/lib/python{X.Y}/site-packages` | :file:`/usr/local/lib/python{X.Y}/site-packages` | \(1) | 259+-----------------+-----------------------------------------------------+--------------------------------------------------+-------+ 260| Unix (non-pure) | :file:`{exec-prefix}/lib/python{X.Y}/site-packages` | :file:`/usr/local/lib/python{X.Y}/site-packages` | \(1) | 261+-----------------+-----------------------------------------------------+--------------------------------------------------+-------+ 262| Windows | :file:`{prefix}\\Lib\\site-packages` | :file:`C:\\Python{XY}\\Lib\\site-packages` | \(2) | 263+-----------------+-----------------------------------------------------+--------------------------------------------------+-------+ 264 265Notes: 266 267(1) 268 Most Linux distributions include Python as a standard part of the system, so 269 :file:`{prefix}` and :file:`{exec-prefix}` are usually both :file:`/usr` on 270 Linux. If you build Python yourself on Linux (or any Unix-like system), the 271 default :file:`{prefix}` and :file:`{exec-prefix}` are :file:`/usr/local`. 272 273(2) 274 The default installation directory on Windows was :file:`C:\\Program 275 Files\\Python` under Python 1.6a1, 1.5.2, and earlier. 276 277:file:`{prefix}` and :file:`{exec-prefix}` stand for the directories that Python 278is installed to, and where it finds its libraries at run-time. They are always 279the same under Windows, and very often the same under Unix and Mac OS X. You 280can find out what your Python installation uses for :file:`{prefix}` and 281:file:`{exec-prefix}` by running Python in interactive mode and typing a few 282simple commands. Under Unix, just type ``python`` at the shell prompt. Under 283Windows, choose :menuselection:`Start --> Programs --> Python X.Y --> 284Python (command line)`. Once the interpreter is started, you type Python code 285at the prompt. For example, on my Linux system, I type the three Python 286statements shown below, and get the output as shown, to find out my 287:file:`{prefix}` and :file:`{exec-prefix}`:: 288 289 Python 2.4 (#26, Aug 7 2004, 17:19:02) 290 Type "help", "copyright", "credits" or "license" for more information. 291 >>> import sys 292 >>> sys.prefix 293 '/usr' 294 >>> sys.exec_prefix 295 '/usr' 296 297A few other placeholders are used in this document: :file:`{X.Y}` stands for the 298version of Python, for example ``2.7``; :file:`{distname}` will be replaced by 299the name of the module distribution being installed. Dots and capitalization 300are important in the paths; for example, a value that uses ``python2.7`` on UNIX 301will typically use ``Python27`` on Windows. 302 303If you don't want to install modules to the standard location, or if you don't 304have permission to write there, then you need to read about alternate 305installations in section :ref:`inst-alt-install`. If you want to customize your 306installation directories more heavily, see section :ref:`inst-custom-install` on 307custom installations. 308 309 310.. _inst-alt-install: 311 312Alternate Installation 313====================== 314 315Often, it is necessary or desirable to install modules to a location other than 316the standard location for third-party Python modules. For example, on a Unix 317system you might not have permission to write to the standard third-party module 318directory. Or you might wish to try out a module before making it a standard 319part of your local Python installation. This is especially true when upgrading 320a distribution already present: you want to make sure your existing base of 321scripts still works with the new version before actually upgrading. 322 323The Distutils :command:`install` command is designed to make installing module 324distributions to an alternate location simple and painless. The basic idea is 325that you supply a base directory for the installation, and the 326:command:`install` command picks a set of directories (called an *installation 327scheme*) under this base directory in which to install files. The details 328differ across platforms, so read whichever of the following sections applies to 329you. 330 331Note that the various alternate installation schemes are mutually exclusive: you 332can pass ``--user``, or ``--home``, or ``--prefix`` and ``--exec-prefix``, or 333``--install-base`` and ``--install-platbase``, but you can't mix from these 334groups. 335 336 337.. _inst-alt-install-user: 338 339Alternate installation: the user scheme 340--------------------------------------- 341 342This scheme is designed to be the most convenient solution for users that don't 343have write permission to the global site-packages directory or don't want to 344install into it. It is enabled with a simple option:: 345 346 python setup.py install --user 347 348Files will be installed into subdirectories of :data:`site.USER_BASE` (written 349as :file:`{userbase}` hereafter). This scheme installs pure Python modules and 350extension modules in the same location (also known as :data:`site.USER_SITE`). 351Here are the values for UNIX, including Mac OS X: 352 353=============== =========================================================== 354Type of file Installation directory 355=============== =========================================================== 356modules :file:`{userbase}/lib/python{X.Y}/site-packages` 357scripts :file:`{userbase}/bin` 358data :file:`{userbase}` 359C headers :file:`{userbase}/include/python{X.Y}/{distname}` 360=============== =========================================================== 361 362And here are the values used on Windows: 363 364=============== =========================================================== 365Type of file Installation directory 366=============== =========================================================== 367modules :file:`{userbase}\\Python{XY}\\site-packages` 368scripts :file:`{userbase}\\Scripts` 369data :file:`{userbase}` 370C headers :file:`{userbase}\\Python{XY}\\Include\\{distname}` 371=============== =========================================================== 372 373The advantage of using this scheme compared to the other ones described below is 374that the user site-packages directory is under normal conditions always included 375in :data:`sys.path` (see :mod:`site` for more information), which means that 376there is no additional step to perform after running the :file:`setup.py` script 377to finalize the installation. 378 379The :command:`build_ext` command also has a ``--user`` option to add 380:file:`{userbase}/include` to the compiler search path for header files and 381:file:`{userbase}/lib` to the compiler search path for libraries as well as to 382the runtime search path for shared C libraries (rpath). 383 384 385.. _inst-alt-install-home: 386 387Alternate installation: the home scheme 388--------------------------------------- 389 390The idea behind the "home scheme" is that you build and maintain a personal 391stash of Python modules. This scheme's name is derived from the idea of a 392"home" directory on Unix, since it's not unusual for a Unix user to make their 393home directory have a layout similar to :file:`/usr/` or :file:`/usr/local/`. 394This scheme can be used by anyone, regardless of the operating system they 395are installing for. 396 397Installing a new module distribution is as simple as :: 398 399 python setup.py install --home=<dir> 400 401where you can supply any directory you like for the :option:`!--home` option. On 402Unix, lazy typists can just type a tilde (``~``); the :command:`install` command 403will expand this to your home directory:: 404 405 python setup.py install --home=~ 406 407To make Python find the distributions installed with this scheme, you may have 408to :ref:`modify Python's search path <inst-search-path>` or edit 409:mod:`sitecustomize` (see :mod:`site`) to call :func:`site.addsitedir` or edit 410:data:`sys.path`. 411 412The :option:`!--home` option defines the installation base directory. Files are 413installed to the following directories under the installation base as follows: 414 415=============== =========================================================== 416Type of file Installation directory 417=============== =========================================================== 418modules :file:`{home}/lib/python` 419scripts :file:`{home}/bin` 420data :file:`{home}` 421C headers :file:`{home}/include/python/{distname}` 422=============== =========================================================== 423 424(Mentally replace slashes with backslashes if you're on Windows.) 425 426.. versionchanged:: 2.4 427 The :option:`!--home` option used to be supported only on Unix. 428 429 430.. _inst-alt-install-prefix-unix: 431 432Alternate installation: Unix (the prefix scheme) 433------------------------------------------------ 434 435The "prefix scheme" is useful when you wish to use one Python installation to 436perform the build/install (i.e., to run the setup script), but install modules 437into the third-party module directory of a different Python installation (or 438something that looks like a different Python installation). If this sounds a 439trifle unusual, it is---that's why the user and home schemes come before. However, 440there are at least two known cases where the prefix scheme will be useful. 441 442First, consider that many Linux distributions put Python in :file:`/usr`, rather 443than the more traditional :file:`/usr/local`. This is entirely appropriate, 444since in those cases Python is part of "the system" rather than a local add-on. 445However, if you are installing Python modules from source, you probably want 446them to go in :file:`/usr/local/lib/python2.{X}` rather than 447:file:`/usr/lib/python2.{X}`. This can be done with :: 448 449 /usr/bin/python setup.py install --prefix=/usr/local 450 451Another possibility is a network filesystem where the name used to write to a 452remote directory is different from the name used to read it: for example, the 453Python interpreter accessed as :file:`/usr/local/bin/python` might search for 454modules in :file:`/usr/local/lib/python2.{X}`, but those modules would have to 455be installed to, say, :file:`/mnt/{@server}/export/lib/python2.{X}`. This could 456be done with :: 457 458 /usr/local/bin/python setup.py install --prefix=/mnt/@server/export 459 460In either case, the :option:`!--prefix` option defines the installation base, and 461the :option:`!--exec-prefix` option defines the platform-specific installation 462base, which is used for platform-specific files. (Currently, this just means 463non-pure module distributions, but could be expanded to C libraries, binary 464executables, etc.) If :option:`!--exec-prefix` is not supplied, it defaults to 465:option:`!--prefix`. Files are installed as follows: 466 467================= ========================================================== 468Type of file Installation directory 469================= ========================================================== 470Python modules :file:`{prefix}/lib/python{X.Y}/site-packages` 471extension modules :file:`{exec-prefix}/lib/python{X.Y}/site-packages` 472scripts :file:`{prefix}/bin` 473data :file:`{prefix}` 474C headers :file:`{prefix}/include/python{X.Y}/{distname}` 475================= ========================================================== 476 477There is no requirement that :option:`!--prefix` or :option:`!--exec-prefix` 478actually point to an alternate Python installation; if the directories listed 479above do not already exist, they are created at installation time. 480 481Incidentally, the real reason the prefix scheme is important is simply that a 482standard Unix installation uses the prefix scheme, but with :option:`!--prefix` 483and :option:`!--exec-prefix` supplied by Python itself as ``sys.prefix`` and 484``sys.exec_prefix``. Thus, you might think you'll never use the prefix scheme, 485but every time you run ``python setup.py install`` without any other options, 486you're using it. 487 488Note that installing extensions to an alternate Python installation has no 489effect on how those extensions are built: in particular, the Python header files 490(:file:`Python.h` and friends) installed with the Python interpreter used to run 491the setup script will be used in compiling extensions. It is your 492responsibility to ensure that the interpreter used to run extensions installed 493in this way is compatible with the interpreter used to build them. The best way 494to do this is to ensure that the two interpreters are the same version of Python 495(possibly different builds, or possibly copies of the same build). (Of course, 496if your :option:`!--prefix` and :option:`!--exec-prefix` don't even point to an 497alternate Python installation, this is immaterial.) 498 499 500.. _inst-alt-install-prefix-windows: 501 502Alternate installation: Windows (the prefix scheme) 503--------------------------------------------------- 504 505Windows has no concept of a user's home directory, and since the standard Python 506installation under Windows is simpler than under Unix, the :option:`!--prefix` 507option has traditionally been used to install additional packages in separate 508locations on Windows. :: 509 510 python setup.py install --prefix="\Temp\Python" 511 512to install modules to the :file:`\\Temp\\Python` directory on the current drive. 513 514The installation base is defined by the :option:`!--prefix` option; the 515:option:`!--exec-prefix` option is not supported under Windows, which means that 516pure Python modules and extension modules are installed into the same location. 517Files are installed as follows: 518 519=============== ========================================================== 520Type of file Installation directory 521=============== ========================================================== 522modules :file:`{prefix}\\Lib\\site-packages` 523scripts :file:`{prefix}\\Scripts` 524data :file:`{prefix}` 525C headers :file:`{prefix}\\Include\\{distname}` 526=============== ========================================================== 527 528 529.. _inst-custom-install: 530 531Custom Installation 532=================== 533 534Sometimes, the alternate installation schemes described in section 535:ref:`inst-alt-install` just don't do what you want. You might want to tweak just 536one or two directories while keeping everything under the same base directory, 537or you might want to completely redefine the installation scheme. In either 538case, you're creating a *custom installation scheme*. 539 540To create a custom installation scheme, you start with one of the alternate 541schemes and override some of the installation directories used for the various 542types of files, using these options: 543 544====================== ======================= 545Type of file Override option 546====================== ======================= 547Python modules ``--install-purelib`` 548extension modules ``--install-platlib`` 549all modules ``--install-lib`` 550scripts ``--install-scripts`` 551data ``--install-data`` 552C headers ``--install-headers`` 553====================== ======================= 554 555These override options can be relative, absolute, 556or explicitly defined in terms of one of the installation base directories. 557(There are two installation base directories, and they are normally the same--- 558they only differ when you use the Unix "prefix scheme" and supply different 559``--prefix`` and ``--exec-prefix`` options; using ``--install-lib`` will 560override values computed or given for ``--install-purelib`` and 561``--install-platlib``, and is recommended for schemes that don't make a 562difference between Python and extension modules.) 563 564For example, say you're installing a module distribution to your home directory 565under Unix---but you want scripts to go in :file:`~/scripts` rather than 566:file:`~/bin`. As you might expect, you can override this directory with the 567:option:`!--install-scripts` option; in this case, it makes most sense to supply 568a relative path, which will be interpreted relative to the installation base 569directory (your home directory, in this case):: 570 571 python setup.py install --home=~ --install-scripts=scripts 572 573Another Unix example: suppose your Python installation was built and installed 574with a prefix of :file:`/usr/local/python`, so under a standard installation 575scripts will wind up in :file:`/usr/local/python/bin`. If you want them in 576:file:`/usr/local/bin` instead, you would supply this absolute directory for the 577:option:`!--install-scripts` option:: 578 579 python setup.py install --install-scripts=/usr/local/bin 580 581(This performs an installation using the "prefix scheme," where the prefix is 582whatever your Python interpreter was installed with--- :file:`/usr/local/python` 583in this case.) 584 585If you maintain Python on Windows, you might want third-party modules to live in 586a subdirectory of :file:`{prefix}`, rather than right in :file:`{prefix}` 587itself. This is almost as easy as customizing the script installation directory 588---you just have to remember that there are two types of modules to worry about, 589Python and extension modules, which can conveniently be both controlled by one 590option:: 591 592 python setup.py install --install-lib=Site 593 594The specified installation directory is relative to :file:`{prefix}`. Of 595course, you also have to ensure that this directory is in Python's module 596search path, such as by putting a :file:`.pth` file in a site directory (see 597:mod:`site`). See section :ref:`inst-search-path` to find out how to modify 598Python's search path. 599 600If you want to define an entire installation scheme, you just have to supply all 601of the installation directory options. The recommended way to do this is to 602supply relative paths; for example, if you want to maintain all Python 603module-related files under :file:`python` in your home directory, and you want a 604separate directory for each platform that you use your home directory from, you 605might define the following installation scheme:: 606 607 python setup.py install --home=~ \ 608 --install-purelib=python/lib \ 609 --install-platlib=python/lib.$PLAT \ 610 --install-scripts=python/scripts 611 --install-data=python/data 612 613or, equivalently, :: 614 615 python setup.py install --home=~/python \ 616 --install-purelib=lib \ 617 --install-platlib='lib.$PLAT' \ 618 --install-scripts=scripts 619 --install-data=data 620 621``$PLAT`` is not (necessarily) an environment variable---it will be expanded by 622the Distutils as it parses your command line options, just as it does when 623parsing your configuration file(s). 624 625Obviously, specifying the entire installation scheme every time you install a 626new module distribution would be very tedious. Thus, you can put these options 627into your Distutils config file (see section :ref:`inst-config-files`):: 628 629 [install] 630 install-base=$HOME 631 install-purelib=python/lib 632 install-platlib=python/lib.$PLAT 633 install-scripts=python/scripts 634 install-data=python/data 635 636or, equivalently, :: 637 638 [install] 639 install-base=$HOME/python 640 install-purelib=lib 641 install-platlib=lib.$PLAT 642 install-scripts=scripts 643 install-data=data 644 645Note that these two are *not* equivalent if you supply a different installation 646base directory when you run the setup script. For example, :: 647 648 python setup.py install --install-base=/tmp 649 650would install pure modules to :file:`/tmp/python/lib` in the first case, and 651to :file:`/tmp/lib` in the second case. (For the second case, you probably 652want to supply an installation base of :file:`/tmp/python`.) 653 654You probably noticed the use of ``$HOME`` and ``$PLAT`` in the sample 655configuration file input. These are Distutils configuration variables, which 656bear a strong resemblance to environment variables. In fact, you can use 657environment variables in config files on platforms that have such a notion but 658the Distutils additionally define a few extra variables that may not be in your 659environment, such as ``$PLAT``. (And of course, on systems that don't have 660environment variables, such as Mac OS 9, the configuration variables supplied by 661the Distutils are the only ones you can use.) See section :ref:`inst-config-files` 662for details. 663 664.. XXX need some Windows examples---when would custom installation schemes be 665 needed on those platforms? 666 667 668.. XXX Move this to Doc/using 669 670.. _inst-search-path: 671 672Modifying Python's Search Path 673------------------------------ 674 675When the Python interpreter executes an :keyword:`import` statement, it searches 676for both Python code and extension modules along a search path. A default value 677for the path is configured into the Python binary when the interpreter is built. 678You can determine the path by importing the :mod:`sys` module and printing the 679value of ``sys.path``. :: 680 681 $ python 682 Python 2.2 (#11, Oct 3 2002, 13:31:27) 683 [GCC 2.96 20000731 (Red Hat Linux 7.3 2.96-112)] on linux2 684 Type "help", "copyright", "credits" or "license" for more information. 685 >>> import sys 686 >>> sys.path 687 ['', '/usr/local/lib/python2.3', '/usr/local/lib/python2.3/plat-linux2', 688 '/usr/local/lib/python2.3/lib-tk', '/usr/local/lib/python2.3/lib-dynload', 689 '/usr/local/lib/python2.3/site-packages'] 690 >>> 691 692The null string in ``sys.path`` represents the current working directory. 693 694The expected convention for locally installed packages is to put them in the 695:file:`{...}/site-packages/` directory, but you may want to install Python 696modules into some arbitrary directory. For example, your site may have a 697convention of keeping all software related to the web server under :file:`/www`. 698Add-on Python modules might then belong in :file:`/www/python`, and in order to 699import them, this directory must be added to ``sys.path``. There are several 700different ways to add the directory. 701 702The most convenient way is to add a path configuration file to a directory 703that's already on Python's path, usually to the :file:`.../site-packages/` 704directory. Path configuration files have an extension of :file:`.pth`, and each 705line must contain a single path that will be appended to ``sys.path``. (Because 706the new paths are appended to ``sys.path``, modules in the added directories 707will not override standard modules. This means you can't use this mechanism for 708installing fixed versions of standard modules.) 709 710Paths can be absolute or relative, in which case they're relative to the 711directory containing the :file:`.pth` file. See the documentation of 712the :mod:`site` module for more information. 713 714A slightly less convenient way is to edit the :file:`site.py` file in Python's 715standard library, and modify ``sys.path``. :file:`site.py` is automatically 716imported when the Python interpreter is executed, unless the :option:`-S` switch 717is supplied to suppress this behaviour. So you could simply edit 718:file:`site.py` and add two lines to it:: 719 720 import sys 721 sys.path.append('/www/python/') 722 723However, if you reinstall the same major version of Python (perhaps when 724upgrading from 2.2 to 2.2.2, for example) :file:`site.py` will be overwritten by 725the stock version. You'd have to remember that it was modified and save a copy 726before doing the installation. 727 728There are two environment variables that can modify ``sys.path``. 729:envvar:`PYTHONHOME` sets an alternate value for the prefix of the Python 730installation. For example, if :envvar:`PYTHONHOME` is set to ``/www/python``, 731the search path will be set to ``['', '/www/python/lib/pythonX.Y/', 732'/www/python/lib/pythonX.Y/plat-linux2', ...]``. 733 734The :envvar:`PYTHONPATH` variable can be set to a list of paths that will be 735added to the beginning of ``sys.path``. For example, if :envvar:`PYTHONPATH` is 736set to ``/www/python:/opt/py``, the search path will begin with 737``['/www/python', '/opt/py']``. (Note that directories must exist in order to 738be added to ``sys.path``; the :mod:`site` module removes paths that don't 739exist.) 740 741Finally, ``sys.path`` is just a regular Python list, so any Python application 742can modify it by adding or removing entries. 743 744 745.. _inst-config-files: 746 747Distutils Configuration Files 748============================= 749 750As mentioned above, you can use Distutils configuration files to record personal 751or site preferences for any Distutils options. That is, any option to any 752command can be stored in one of two or three (depending on your platform) 753configuration files, which will be consulted before the command-line is parsed. 754This means that configuration files will override default values, and the 755command-line will in turn override configuration files. Furthermore, if 756multiple configuration files apply, values from "earlier" files are overridden 757by "later" files. 758 759 760.. _inst-config-filenames: 761 762Location and names of config files 763---------------------------------- 764 765The names and locations of the configuration files vary slightly across 766platforms. On Unix and Mac OS X, the three configuration files (in the order 767they are processed) are: 768 769+--------------+----------------------------------------------------------+-------+ 770| Type of file | Location and filename | Notes | 771+==============+==========================================================+=======+ 772| system | :file:`{prefix}/lib/python{ver}/distutils/distutils.cfg` | \(1) | 773+--------------+----------------------------------------------------------+-------+ 774| personal | :file:`$HOME/.pydistutils.cfg` | \(2) | 775+--------------+----------------------------------------------------------+-------+ 776| local | :file:`setup.cfg` | \(3) | 777+--------------+----------------------------------------------------------+-------+ 778 779And on Windows, the configuration files are: 780 781+--------------+-------------------------------------------------+-------+ 782| Type of file | Location and filename | Notes | 783+==============+=================================================+=======+ 784| system | :file:`{prefix}\\Lib\\distutils\\distutils.cfg` | \(4) | 785+--------------+-------------------------------------------------+-------+ 786| personal | :file:`%HOME%\\pydistutils.cfg` | \(5) | 787+--------------+-------------------------------------------------+-------+ 788| local | :file:`setup.cfg` | \(3) | 789+--------------+-------------------------------------------------+-------+ 790 791On all platforms, the "personal" file can be temporarily disabled by 792passing the `--no-user-cfg` option. 793 794Notes: 795 796(1) 797 Strictly speaking, the system-wide configuration file lives in the directory 798 where the Distutils are installed; under Python 1.6 and later on Unix, this is 799 as shown. For Python 1.5.2, the Distutils will normally be installed to 800 :file:`{prefix}/lib/python1.5/site-packages/distutils`, so the system 801 configuration file should be put there under Python 1.5.2. 802 803(2) 804 On Unix, if the :envvar:`HOME` environment variable is not defined, the user's 805 home directory will be determined with the :func:`getpwuid` function from the 806 standard :mod:`pwd` module. This is done by the :func:`os.path.expanduser` 807 function used by Distutils. 808 809(3) 810 I.e., in the current directory (usually the location of the setup script). 811 812(4) 813 (See also note (1).) Under Python 1.6 and later, Python's default "installation 814 prefix" is :file:`C:\\Python`, so the system configuration file is normally 815 :file:`C:\\Python\\Lib\\distutils\\distutils.cfg`. Under Python 1.5.2, the 816 default prefix was :file:`C:\\Program Files\\Python`, and the Distutils were not 817 part of the standard library---so the system configuration file would be 818 :file:`C:\\Program Files\\Python\\distutils\\distutils.cfg` in a standard Python 819 1.5.2 installation under Windows. 820 821(5) 822 On Windows, if the :envvar:`HOME` environment variable is not defined, 823 :envvar:`USERPROFILE` then :envvar:`HOMEDRIVE` and :envvar:`HOMEPATH` will 824 be tried. This is done by the :func:`os.path.expanduser` function used 825 by Distutils. 826 827 828.. _inst-config-syntax: 829 830Syntax of config files 831---------------------- 832 833The Distutils configuration files all have the same syntax. The config files 834are grouped into sections. There is one section for each Distutils command, 835plus a ``global`` section for global options that affect every command. Each 836section consists of one option per line, specified as ``option=value``. 837 838For example, the following is a complete config file that just forces all 839commands to run quietly by default:: 840 841 [global] 842 verbose=0 843 844If this is installed as the system config file, it will affect all processing of 845any Python module distribution by any user on the current system. If it is 846installed as your personal config file (on systems that support them), it will 847affect only module distributions processed by you. And if it is used as the 848:file:`setup.cfg` for a particular module distribution, it affects only that 849distribution. 850 851You could override the default "build base" directory and make the 852:command:`build\*` commands always forcibly rebuild all files with the 853following:: 854 855 [build] 856 build-base=blib 857 force=1 858 859which corresponds to the command-line arguments :: 860 861 python setup.py build --build-base=blib --force 862 863except that including the :command:`build` command on the command-line means 864that command will be run. Including a particular command in config files has no 865such implication; it only means that if the command is run, the options in the 866config file will apply. (Or if other commands that derive values from it are 867run, they will use the values in the config file.) 868 869You can find out the complete list of options for any command using the 870:option:`!--help` option, e.g.:: 871 872 python setup.py build --help 873 874and you can find out the complete list of global options by using 875:option:`!--help` without a command:: 876 877 python setup.py --help 878 879See also the "Reference" section of the "Distributing Python Modules" manual. 880 881 882.. _inst-building-ext: 883 884Building Extensions: Tips and Tricks 885==================================== 886 887Whenever possible, the Distutils try to use the configuration information made 888available by the Python interpreter used to run the :file:`setup.py` script. 889For example, the same compiler and linker flags used to compile Python will also 890be used for compiling extensions. Usually this will work well, but in 891complicated situations this might be inappropriate. This section discusses how 892to override the usual Distutils behaviour. 893 894 895.. _inst-tweak-flags: 896 897Tweaking compiler/linker flags 898------------------------------ 899 900Compiling a Python extension written in C or C++ will sometimes require 901specifying custom flags for the compiler and linker in order to use a particular 902library or produce a special kind of object code. This is especially true if the 903extension hasn't been tested on your platform, or if you're trying to 904cross-compile Python. 905 906In the most general case, the extension author might have foreseen that 907compiling the extensions would be complicated, and provided a :file:`Setup` file 908for you to edit. This will likely only be done if the module distribution 909contains many separate extension modules, or if they often require elaborate 910sets of compiler flags in order to work. 911 912A :file:`Setup` file, if present, is parsed in order to get a list of extensions 913to build. Each line in a :file:`Setup` describes a single module. Lines have 914the following structure:: 915 916 module ... [sourcefile ...] [cpparg ...] [library ...] 917 918 919Let's examine each of the fields in turn. 920 921* *module* is the name of the extension module to be built, and should be a 922 valid Python identifier. You can't just change this in order to rename a module 923 (edits to the source code would also be needed), so this should be left alone. 924 925* *sourcefile* is anything that's likely to be a source code file, at least 926 judging by the filename. Filenames ending in :file:`.c` are assumed to be 927 written in C, filenames ending in :file:`.C`, :file:`.cc`, and :file:`.c++` are 928 assumed to be C++, and filenames ending in :file:`.m` or :file:`.mm` are assumed 929 to be in Objective C. 930 931* *cpparg* is an argument for the C preprocessor, and is anything starting with 932 :option:`!-I`, :option:`!-D`, :option:`!-U` or :option:`!-C`. 933 934* *library* is anything ending in :file:`.a` or beginning with :option:`!-l` or 935 :option:`!-L`. 936 937If a particular platform requires a special library on your platform, you can 938add it by editing the :file:`Setup` file and running ``python setup.py build``. 939For example, if the module defined by the line :: 940 941 foo foomodule.c 942 943must be linked with the math library :file:`libm.a` on your platform, simply add 944:option:`!-lm` to the line:: 945 946 foo foomodule.c -lm 947 948Arbitrary switches intended for the compiler or the linker can be supplied with 949the :option:`!-Xcompiler` *arg* and :option:`!-Xlinker` *arg* options:: 950 951 foo foomodule.c -Xcompiler -o32 -Xlinker -shared -lm 952 953The next option after :option:`!-Xcompiler` and :option:`!-Xlinker` will be 954appended to the proper command line, so in the above example the compiler will 955be passed the :option:`!-o32` option, and the linker will be passed 956:option:`!-shared`. If a compiler option requires an argument, you'll have to 957supply multiple :option:`!-Xcompiler` options; for example, to pass ``-x c++`` 958the :file:`Setup` file would have to contain ``-Xcompiler -x -Xcompiler c++``. 959 960Compiler flags can also be supplied through setting the :envvar:`CFLAGS` 961environment variable. If set, the contents of :envvar:`CFLAGS` will be added to 962the compiler flags specified in the :file:`Setup` file. 963 964 965.. _inst-non-ms-compilers: 966 967Using non-Microsoft compilers on Windows 968---------------------------------------- 969 970.. sectionauthor:: Rene Liebscher <R.Liebscher@gmx.de> 971 972 973 974Borland/CodeGear C++ 975^^^^^^^^^^^^^^^^^^^^ 976 977This subsection describes the necessary steps to use Distutils with the Borland 978C++ compiler version 5.5. First you have to know that Borland's object file 979format (OMF) is different from the format used by the Python version you can 980download from the Python or ActiveState Web site. (Python is built with 981Microsoft Visual C++, which uses COFF as the object file format.) For this 982reason you have to convert Python's library :file:`python25.lib` into the 983Borland format. You can do this as follows: 984 985.. Should we mention that users have to create cfg-files for the compiler? 986.. see also http://community.borland.com/article/0,1410,21205,00.html 987 988:: 989 990 coff2omf python25.lib python25_bcpp.lib 991 992The :file:`coff2omf` program comes with the Borland compiler. The file 993:file:`python25.lib` is in the :file:`Libs` directory of your Python 994installation. If your extension uses other libraries (zlib, ...) you have to 995convert them too. 996 997The converted files have to reside in the same directories as the normal 998libraries. 999 1000How does Distutils manage to use these libraries with their changed names? If 1001the extension needs a library (eg. :file:`foo`) Distutils checks first if it 1002finds a library with suffix :file:`_bcpp` (eg. :file:`foo_bcpp.lib`) and then 1003uses this library. In the case it doesn't find such a special library it uses 1004the default name (:file:`foo.lib`.) [#]_ 1005 1006To let Distutils compile your extension with Borland C++ you now have to type:: 1007 1008 python setup.py build --compiler=bcpp 1009 1010If you want to use the Borland C++ compiler as the default, you could specify 1011this in your personal or system-wide configuration file for Distutils (see 1012section :ref:`inst-config-files`.) 1013 1014 1015.. seealso:: 1016 1017 `C++Builder Compiler <https://www.embarcadero.com/products>`_ 1018 Information about the free C++ compiler from Borland, including links to the 1019 download pages. 1020 1021 `Creating Python Extensions Using Borland's Free Compiler <http://www.cyberus.ca/~g_will/pyExtenDL.shtml>`_ 1022 Document describing how to use Borland's free command-line C++ compiler to build 1023 Python. 1024 1025 1026GNU C / Cygwin / MinGW 1027^^^^^^^^^^^^^^^^^^^^^^ 1028 1029This section describes the necessary steps to use Distutils with the GNU C/C++ 1030compilers in their Cygwin and MinGW distributions. [#]_ For a Python interpreter 1031that was built with Cygwin, everything should work without any of these 1032following steps. 1033 1034Not all extensions can be built with MinGW or Cygwin, but many can. Extensions 1035most likely to not work are those that use C++ or depend on Microsoft Visual C 1036extensions. 1037 1038To let Distutils compile your extension with Cygwin you have to type:: 1039 1040 python setup.py build --compiler=cygwin 1041 1042and for Cygwin in no-cygwin mode [#]_ or for MinGW type:: 1043 1044 python setup.py build --compiler=mingw32 1045 1046If you want to use any of these options/compilers as default, you should 1047consider writing it in your personal or system-wide configuration file for 1048Distutils (see section :ref:`inst-config-files`.) 1049 1050Older Versions of Python and MinGW 1051"""""""""""""""""""""""""""""""""" 1052The following instructions only apply if you're using a version of Python 1053inferior to 2.4.1 with a MinGW inferior to 3.0.0 (with 1054binutils-2.13.90-20030111-1). 1055 1056These compilers require some special libraries. This task is more complex than 1057for Borland's C++, because there is no program to convert the library. First 1058you have to create a list of symbols which the Python DLL exports. (You can find 1059a good program for this task at 1060https://sourceforge.net/projects/mingw/files/MinGW/Extension/pexports/). 1061 1062.. I don't understand what the next line means. --amk 1063.. (inclusive the references on data structures.) 1064 1065:: 1066 1067 pexports python25.dll >python25.def 1068 1069The location of an installed :file:`python25.dll` will depend on the 1070installation options and the version and language of Windows. In a "just for 1071me" installation, it will appear in the root of the installation directory. In 1072a shared installation, it will be located in the system directory. 1073 1074Then you can create from these information an import library for gcc. :: 1075 1076 /cygwin/bin/dlltool --dllname python25.dll --def python25.def --output-lib libpython25.a 1077 1078The resulting library has to be placed in the same directory as 1079:file:`python25.lib`. (Should be the :file:`libs` directory under your Python 1080installation directory.) 1081 1082If your extension uses other libraries (zlib,...) you might have to convert 1083them too. The converted files have to reside in the same directories as the 1084normal libraries do. 1085 1086 1087.. seealso:: 1088 1089 `Building Python modules on MS Windows platform with MinGW <http://old.zope.org/Members/als/tips/win32_mingw_modules>`_ 1090 Information about building the required libraries for the MinGW environment. 1091 1092 1093.. rubric:: Footnotes 1094 1095.. [#] This also means you could replace all existing COFF-libraries with OMF-libraries 1096 of the same name. 1097 1098.. [#] Check https://www.sourceware.org/cygwin/ and http://www.mingw.org/ for more 1099 information 1100 1101.. [#] Then you have no POSIX emulation available, but you also don't need 1102 :file:`cygwin1.dll`. 1103