.. highlightlang:: none
.. sectionauthor:: Robert Lehmann <lehmannro@gmail.com>
This document aims to give an overview of Windows-specific behaviour you should know about when using Python on Microsoft Windows.
Unlike most Unix systems and services, Windows does not require Python natively and thus does not pre-install a version of Python. However, the CPython team has compiled Windows installers (MSI packages) with every release for many years.
With ongoing development of Python, some platforms that used to be supported earlier are no longer supported (due to the lack of users or developers). Check PEP 11 for details on all unsupported platforms.
- DOS and Windows 3.x are deprecated since Python 2.0 and code specific to these systems was removed in Python 2.1.
- Up to 2.5, Python was still compatible with Windows 95, 98 and ME (but already raised a deprecation warning on installation). For Python 2.6 (and all following releases), this support was dropped and new releases are just expected to work on the Windows NT family.
- Windows CE is still supported.
- The Cygwin installer offers to install the Python interpreter as well; it is located under "Interpreters." (cf. Cygwin package source, Maintainer releases)
See Python for Windows (and DOS) for detailed information about platforms with precompiled installers.
.. seealso::
`Python on XP <http://www.richarddooling.com/index.php/2006/03/14/python-on-xp-7-minutes-to-hello-world/>`_
"7 Minutes to "Hello World!""
by Richard Dooling, 2006
`Installing on Windows <http://diveintopython.org/installing_python/windows.html>`_
in "`Dive into Python: Python from novice to pro
<http://diveintopython.org/index.html>`_"
by Mark Pilgrim, 2004,
ISBN 1-59059-356-1
`For Windows users <http://swaroopch.com/text/Byte_of_Python:Installing_Python#For_Windows_users>`_
in "Installing Python"
in "`A Byte of Python <http://www.byteofpython.info>`_"
by Swaroop C H, 2003
Besides the standard CPython distribution, there are modified packages including additional functionality. The following is a list of popular versions and their key features:
- ActivePython
- Installer with multi-platform compatibility, documentation, PyWin32
- Python Enthought Edition
- Popular modules (such as PyWin32) with their respective documentation, tool suite for building extensible python applications
Notice that these packages are likely to install older versions of Python.
In order to run Python flawlessly, you might have to change certain environment settings in Windows.
Windows has a built-in dialog for changing environment variables (following guide applies to XP classical view): Right-click the icon for your machine (usually located on your Desktop and called "My Computer") and choose :menuselection:`Properties` there. Then, open the :guilabel:`Advanced` tab and click the :guilabel:`Environment Variables` button.
In short, your path is:
:menuselection:`My Computer --> Properties --> Advanced --> Environment Variables`
In this dialog, you can add or modify User and System variables. To change System variables, you need non-restricted access to your machine (i.e. Administrator rights).
Another way of adding variables to your environment is using the :command:`set` command:
set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib
To make this setting permanent, you could add the corresponding command line to your :file:`autoexec.bat`. :program:`msconfig` is a graphical interface to this file.
Viewing environment variables can also be done more straight-forward: The command prompt will expand strings wrapped into percent signs automatically:
echo %PATH%
Consult :command:`set /?` for details on this behaviour.
.. seealso::
http://support.microsoft.com/kb/100843
Environment variables in Windows NT
http://support.microsoft.com/kb/310519
How To Manage Environment Variables in Windows XP
http://www.chem.gla.ac.uk/~louis/software/faq/q1.html
Setting Environment variables, Louis J. Farrugia
Besides using the automatically created start menu entry for the Python interpreter, you might want to start Python in the DOS prompt. To make this work, you need to set your :envvar:`%PATH%` environment variable to include the directory of your Python distribution, delimited by a semicolon from other entries. An example variable could look like this (assuming the first two entries are Windows' default):
C:\WINDOWS\system32;C:\WINDOWS;C:\Python25
Typing :command:`python` on your command prompt will now fire up the Python interpreter. Thus, you can also execute your scripts with command line options, see :ref:`using-on-cmdline` documentation.
Python usually stores its library (and thereby your site-packages folder) in the installation directory. So, if you had installed Python to :file:`C:\\Python\\`, the default library would reside in :file:`C:\\Python\\Lib\\` and third-party modules should be stored in :file:`C:\\Python\\Lib\\site-packages\\`.
You can add folders to your search path to make Python's import mechanism search in these directories as well. Use :envvar:`PYTHONPATH`, as described in :ref:`using-on-envvars`, to modify :data:`sys.path`. On Windows, paths are separated by semicolons, though, to distinguish them from drive identifiers (:file:`C:\\` etc.).
Modifying the module search path can also be done through the Windows registry: Edit :file:`HKEY_LOCAL_MACHINE\\SOFTWARE\\Python\\PythonCore\\{version}\\PythonPath\\`, as described above for the environment variable :envvar:`%PYTHONPATH%`. A convenient registry editor is :program:`regedit` (start it by typing "regedit" into :menuselection:`Start --> Run`).
Python scripts (files with the extension .py) will be executed by
:program:`python.exe` by default. This executable opens a terminal, which stays
open even if the program uses a GUI. If you do not want this to happen, use the
extension .pyw which will cause the script to be executed by
:program:`pythonw.exe` by default (both executables are located in the top-level
of your Python installation directory). This suppresses the terminal window on
startup.
You can also make all .py scripts execute with :program:`pythonw.exe`,
setting this through the usual facilities, for example (might require
administrative rights):
Launch a command prompt.
Associate the correct file group with
.pyscripts:assoc .py=Python.File
Redirect all Python files to the new executable:
ftype Python.File=C:\Path\to\pythonw.exe "%1" %*
Even though Python aims to be portable among all platforms, there are features that are unique to Windows. A couple of modules, both in the standard library and external, and snippets exist to use these features.
The Windows-specific standard modules are documented in :ref:`mswin-specific-services`.
The PyWin32 module by Mark Hammond is a collection of modules for advanced Windows-specific support. This includes utilities for:
- Component Object Model (COM)
- Win32 API calls
- Registry
- Event log
- Microsoft Foundation Classes (MFC) user interfaces
PythonWin is a sample MFC application shipped with PyWin32. It is an embeddable IDE with a built-in debugger.
.. seealso::
`Win32 How Do I...? <http://timgolden.me.uk/python/win32_how_do_i.html>`_
by Tim Golden
`Python and COM <http://www.boddie.org.uk/python/COM.html>`_
by David and Paul Boddie
Py2exe is a :mod:`distutils` extension (see :ref:`extending-distutils`) which wraps Python scripts into executable Windows programs (:file:`{*}.exe` files). When you have done this, you can distribute your application without requiring your users to install Python.
Since Python's advanced terminal handling layer, :mod:`curses`, is restricted to Unix-like systems, there is a library exclusive to Windows as well: Windows Console I/O for Python.
WConio is a wrapper for Turbo-C's :file:`CONIO.H`, used to create text user interfaces.
If you want to compile CPython yourself, first thing you should do is get the source. You can download either the latest release's source or just grab a fresh checkout.
For Microsoft Visual C++, which is the compiler with which official Python releases are built, the source tree contains solutions/project files. View the :file:`readme.txt` in their respective directories:
| Directory | MSVC version | Visual Studio version |
|---|---|---|
| :file:`PC/VC6/` | 6.0 | 97 |
| :file:`PC/VS7.1/` | 7.1 | 2003 |
| :file:`PC/VS8.0/` | 8.0 | 2005 |
| :file:`PCbuild/` | 9.0 | 2008 |
Note that not all of these build directories are fully supported. Read the release notes to see which compiler version the official releases for your version are built with.
Check :file:`PC/readme.txt` for general information on the build process.
For extension modules, consult :ref:`building-on-windows`.
.. seealso::
`Python + Windows + distutils + SWIG + gcc MinGW <http://sebsauvage.net/python/mingw.html>`_
or "Creating Python extensions in C/C++ with SWIG and compiling them with
MinGW gcc under Windows" or "Installing Python extension with distutils
and without Microsoft Visual C++" by Sébastien Sauvage, 2003
`MingW -- Python extensions <http://www.mingw.org/MinGWiki/index.php/Python%20extensions>`_
by Trent Apted et al, 2007
.. seealso::
`Python Programming On Win32 <http://www.oreilly.com/catalog/pythonwin32/>`_
"Help for Windows Programmers"
by Mark Hammond and Andy Robinson, O'Reilly Media, 2000,
ISBN 1-56592-621-8
`A Python for Windows Tutorial <http://www.imladris.com/Scripts/PythonForWindows.html>`_
by Amanda Birmingham, 2004