diff options
Diffstat (limited to 'Doc/using/windows.rst')
| -rw-r--r-- | Doc/using/windows.rst | 669 |
1 files changed, 493 insertions, 176 deletions
diff --git a/Doc/using/windows.rst b/Doc/using/windows.rst index c05f72a..2116c10 100644 --- a/Doc/using/windows.rst +++ b/Doc/using/windows.rst @@ -7,22 +7,213 @@ ************************* .. sectionauthor:: Robert Lehmann <lehmannro@gmail.com> +.. sectionauthor:: Steve Dower <steve.dower@microsoft.com> This document aims to give an overview of Windows-specific behaviour you should know about when using Python on Microsoft Windows. -.. XXX (ncoghlan) - - This looks rather stale to me... - - Installing Python ================= -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 +Unlike most Unix systems and services, Windows does not include a system +supported installation of Python. To make Python available, the CPython team has compiled Windows installers (MSI packages) with every `release -<https://www.python.org/download/releases/>`_ for many years. +<https://www.python.org/download/releases/>`_ for many years. These installers +are primarily intended to add a per-user installation of Python, with the +core interpreter and library being used by a single user. The installer is also +able to install for all users of a single machine, and a separate ZIP file is +available for application-local distributions. + +Installation Steps +------------------ + +Four Python 3.5 installers are available for download - two each for the 32-bit +and 64-bit versions of the interpreter. The *web installer* is a small initial +download, and it will automatically download the required components as +necessary. The *offline installer* includes the components necessary for a +default installation and only requires an internet connection for optional +features. See :ref:`install-layout-option` for other ways to avoid downloading +during installation. + +After starting the installer, one of two options may be selected: + +.. image:: win_installer.png + +If you select "Install Now": + +* You will *not* need to be an administrator (unless a system update for the + C Runtime Library is required or you install the :ref:`launcher` for all + users) +* Python will be installed into your user directory +* The :ref:`launcher` will be installed according to the option at the bottom + of the first pace +* The standard library, test suite, launcher and pip will be installed +* If selected, the install directory will be added to your :envvar:`PATH` +* Shortcuts will only be visible for the current user + +Selecting "Customize installation" will allow you to select the features to +install, the installation location and other options or post-install actions. +To install debugging symbols or binaries, you will need to use this option. + +To perform an all-users installation, you should select "Customize +installation". In this case: + +* You may be required to provide administrative credentials or approval +* Python will be installed into the Program Files directory +* The :ref:`launcher` will be installed into the Windows directory +* Optional features may be selected during installation +* The standard library can be pre-compiled to bytecode +* If selected, the install directory will be added to the system :envvar:`PATH` +* Shortcuts are available for all users + +.. _install-quiet-option: + +Installing Without UI +--------------------- + +All of the options available in the installer UI can also be specified from the +command line, allowing scripted installers to replicate an installation on many +machines without user interaction. These options may also be set without +suppressing the UI in order to change some of the defaults. + +To completely hide the installer UI and install Python silently, pass the +``/quiet`` option. To skip past the user interaction but still display +progress and errors, pass the ``/passive`` option. The ``/uninstall`` +option may be passed to immediately begin removing Python - no prompt will be +displayed. + +All other options are passed as ``name=value``, where the value is usually +``0`` to disable a feature, ``1`` to enable a feature, or a path. The full list +of available options is shown below. + ++---------------------------+--------------------------------------+--------------------------+ +| Name | Description | Default | ++===========================+======================================+==========================+ +| InstallAllUsers | Perform a system-wide installation. | 0 | ++---------------------------+--------------------------------------+--------------------------+ +| TargetDir | The installation directory | Selected based on | +| | | InstallAllUsers | ++---------------------------+--------------------------------------+--------------------------+ +| DefaultAllUsersTargetDir | The default installation directory | :file:`%ProgramFiles%\\\ | +| | for all-user installs | Python X.Y` or :file:`\ | +| | | %ProgramFiles(x86)%\\\ | +| | | Python X.Y` | ++---------------------------+--------------------------------------+--------------------------+ +| DefaultJustForMeTargetDir | The default install directory for | :file:`%LocalAppData%\\\ | +| | just-for-me installs | Programs\\PythonXY` or | +| | | :file:`%LocalAppData%\\\ | +| | | Programs\\PythonXY-32` | ++---------------------------+--------------------------------------+--------------------------+ +| DefaultCustomTargetDir | The default custom install directory | (empty) | +| | displayed in the UI | | ++---------------------------+--------------------------------------+--------------------------+ +| AssociateFiles | Create file associations if the | 1 | +| | launcher is also installed. | | ++---------------------------+--------------------------------------+--------------------------+ +| CompileAll | Compile all ``.py`` files to | 0 | +| | ``.pyc``. | | ++---------------------------+--------------------------------------+--------------------------+ +| PrependPath | Add install and Scripts directories | 0 | +| | tho :envvar:`PATH` and ``.PY`` to | | +| | :envvar:`PATHEXT` | | ++---------------------------+--------------------------------------+--------------------------+ +| Shortcuts | Create shortcuts for the interpreter,| 1 | +| | documentation and IDLE if installed. | | ++---------------------------+--------------------------------------+--------------------------+ +| Include_doc | Install Python manual | 1 | ++---------------------------+--------------------------------------+--------------------------+ +| Include_debug | Install debug binaries | 0 | ++---------------------------+--------------------------------------+--------------------------+ +| Include_dev | Install developer headers and | 1 | +| | libraries | | ++---------------------------+--------------------------------------+--------------------------+ +| Include_exe | Install :file:`python.exe` and | 1 | +| | related files | | ++---------------------------+--------------------------------------+--------------------------+ +| Include_launcher | Install :ref:`launcher`. | 1 | ++---------------------------+--------------------------------------+--------------------------+ +| InstallLauncherAllUsers | Installs :ref:`launcher` for all | 1 | +| | users. | | ++---------------------------+--------------------------------------+--------------------------+ +| Include_lib | Install standard library and | 1 | +| | extension modules | | ++---------------------------+--------------------------------------+--------------------------+ +| Include_pip | Install bundled pip and setuptools | 1 | ++---------------------------+--------------------------------------+--------------------------+ +| Include_symbols | Install debugging symbols (`*`.pdb) | 0 | ++---------------------------+--------------------------------------+--------------------------+ +| Include_tcltk | Install Tcl/Tk support and IDLE | 1 | ++---------------------------+--------------------------------------+--------------------------+ +| Include_test | Install standard library test suite | 1 | ++---------------------------+--------------------------------------+--------------------------+ +| Include_tools | Install utility scripts | 1 | ++---------------------------+--------------------------------------+--------------------------+ +| LauncherOnly | Only installs the launcher. This | 0 | +| | will override most other options. | | ++---------------------------+--------------------------------------+--------------------------+ +| SimpleInstall | Disable most install UI | 0 | ++---------------------------+--------------------------------------+--------------------------+ +| SimpleInstallDescription | A custom message to display when the | (empty) | +| | simplified install UI is used. | | ++---------------------------+--------------------------------------+--------------------------+ + +For example, to silently install a default, system-wide Python installation, +you could use the following command (from an elevated command prompt):: + + python-3.5.0.exe /quiet InstallAllUsers=1 PrependPath=1 Include_test=0 + +To allow users to easily install a personal copy of Python without the test +suite, you could provide a shortcut with the following command. This will +display a simplified initial page and disallow customization:: + + python-3.5.0.exe InstallAllUsers=0 Include_launcher=0 Include_test=0 + SimpleInstall=1 SimpleInstallDescription="Just for me, no test suite." + +(Note that omitting the launcher also omits file associations, and is only +recommended for per-user installs when there is also a system-wide installation +that included the launcher.) + +The options listed above can also be provided in a file named ``unattend.xml`` +alongside the executable. This file specifies a list of options and values. +When a value is provided as an attribute, it will be converted to a number if +possible. Values provided as element text are always left as strings. This +example file sets the same options and the previous example:: + + <Options> + <Option Name="InstallAllUsers" Value="no" /> + <Option Name="Include_launcher" Value="0" /> + <Option Name="Include_test" Value="no" /> + <Option Name="SimpleInstall" Value="yes" /> + <Option Name="SimpleInstallDescription">Just for me, no test suite</Option> + </Options> + +.. _install-layout-option: + +Installing Without Downloading +------------------------------ + +As some features of Python are not included in the initial installer download, +selecting those features may require an internet connection. To avoid this +need, all possible components may be downloaded on-demand to create a complete +*layout* that will no longer require an internet connection regardless of the +selected features. Note that this download may be bigger than required, but +where a large number of installations are going to be performed it is very +useful to have a locally cached copy. + +Execute the following command from Command Prompt to download all possible +required files. Remember to substitute ``python-3.5.0.exe`` for the actual +name of your installer, and to create layouts in their own directories to +avoid collisions between files with the same name. + +:: + + python-3.5.0.exe /layout [optional target directory] + +You may also specify the ``/quiet`` option to hide the progress display. + + +Other Platforms +--------------- 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). @@ -66,19 +257,31 @@ key features: `ActivePython <http://www.activestate.com/activepython/>`_ Installer with multi-platform compatibility, documentation, PyWin32 -`Enthought Python Distribution <https://www.enthought.com/products/epd/>`_ - Popular modules (such as PyWin32) with their respective documentation, tool - suite for building extensible Python applications +`Anaconda <http://www.continuum.io/downloads/>`_ + Popular scientific modules (such as numpy, scipy and pandas) and the + ``conda`` package manager. + +`Canopy <https://www.enthought.com/products/canopy/>`_ + A "comprehensive Python analysis environment" with editors and other + development tools. -Notice that these packages are likely to install *older* versions of Python. +`WinPython <https://winpython.github.io/>`_ + Windows-specific distribution with prebuilt scientific packages and + tools for building packages. + +Note that these packages may not include the latest versions of Python or +other libraries, and are not maintained or supported by the core Python team. Configuring Python ================== -In order to run Python flawlessly, you might have to change certain environment -settings in Windows. +To run Python conveniently from a command prompt, you might consider changing +some default environment variables in Windows. While the installer provides an +option to configure the PATH and PATHEXT variables for you, this is only +reliable for a single, system-wide installation. If you regularly use multiple +versions of Python, consider using the :ref:`launcher`. .. _setting-envvars: @@ -86,163 +289,86 @@ settings in Windows. Excursus: Setting environment variables --------------------------------------- -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. +Windows allows environment variables to be configured permanently at both the +User level and the System level, or temporarily in a command prompt. + +To temporarily set environment variables, open Command Prompt and use the +:command:`set` command:: + + C:\>set PATH=C:\Program Files\Python 3.5;%PATH% + C:\>set PYTHONPATH=%PYTHONPATH%;C:\My_python_lib + C:\>python -In short, your path is: +These changes will apply to any further commands executed in that console, and +will be inherited by any applications started from the console. - :menuselection:`My Computer - --> Properties - --> Advanced - --> Environment Variables` +Including the variable name within percent signs will expand to the existing +value, allowing you to add your new value at either the start or the end. +Modifying :envvar:`PATH` by adding the directory containing +:program:`python.exe` to the start is a common way to ensure the correct version +of Python is launched. +To permanently modify the default environment variables, click Start and search +for 'edit environment variables', or open System properties, :guilabel:`Advanced +system settings` and click the :guilabel:`Environment Variables` button. 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. +.. note:: -Viewing environment variables can also be done more straight-forward: The -command prompt will expand strings wrapped into percent signs automatically:: + Windows will concatenate User variables *after* System variables, which may + cause unexpected results when modifying :envvar:`PATH`. - echo %PATH% - -Consult :command:`set /?` for details on this behaviour. + The :envvar:`PYTHONPATH` variable is used by all versions of Python 2 and + Python 3, so you should not permanently configure this variable unless it + only includes code that is compatible with all of your installed Python + versions. .. seealso:: - http://support.microsoft.com/kb/100843 + http://support.microsoft.com/kb/100843 Environment variables in Windows NT - http://support.microsoft.com/kb/310519 + http://technet.microsoft.com/en-us/library/cc754250.aspx + The SET command, for temporarily modifying environment variables + + http://technet.microsoft.com/en-us/library/cc755104.aspx + The SETX command, for permanently modifying environment variables + + 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 + http://www.chem.gla.ac.uk/~louis/software/faq/q1.html Setting Environment variables, Louis J. Farrugia - .. _windows-path-mod: Finding the Python executable ----------------------------- -.. versionchanged:: 3.3 +.. versionchanged:: 3.5 Besides using the automatically created start menu entry for the Python -interpreter, you might want to start Python in the command prompt. As of -Python 3.3, the installer has an option to set that up for you. - -At the "Customize Python 3.3" screen, an option called -"Add python.exe to search path" can be enabled to have the installer place -your installation into the :envvar:`%PATH%`. This allows you to type -:command:`python` to run the interpreter. Thus, you can also execute your +interpreter, you might want to start Python in the command prompt. The +installer for Python 3.5 and later has an option to set that up for you. + +On the first page of the installer, an option labelled "Add Python 3.5 to +PATH" can be selected to have the installer add the install location into the +:envvar:`PATH`. The location of the :file:`Scripts\\` folder is also added. +This allows you to type :command:`python` to run the interpreter, and +:command:`pip` or . Thus, you can also execute your scripts with command line options, see :ref:`using-on-cmdline` documentation. If you don't enable this option at install time, you can always re-run the -installer to choose it. - -The alternative is manually modifying the :envvar:`%PATH%` using the -directions in :ref:`setting-envvars`. 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:\Python33 - - -Finding modules ---------------- - -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\\`. - -This is how :data:`sys.path` is populated on Windows: - -* An empty entry is added at the start, which corresponds to the current - directory. - -* If the environment variable :envvar:`PYTHONPATH` exists, as described in - :ref:`using-on-envvars`, its entries are added next. Note that on Windows, - paths in this variable must be separated by semicolons, to distinguish them - from the colon used in drive identifiers (``C:\`` etc.). - -* Additional "application paths" can be added in the registry as subkeys of - :samp:`\\SOFTWARE\\Python\\PythonCore\\{version}\\PythonPath` under both the - ``HKEY_CURRENT_USER`` and ``HKEY_LOCAL_MACHINE`` hives. Subkeys which have - semicolon-delimited path strings as their default value will cause each path - to be added to :data:`sys.path`. (Note that all known installers only use - HKLM, so HKCU is typically empty.) - -* If the environment variable :envvar:`PYTHONHOME` is set, it is assumed as - "Python Home". Otherwise, the path of the main Python executable is used to - locate a "landmark file" (``Lib\os.py``) to deduce the "Python Home". If a - Python home is found, the relevant sub-directories added to :data:`sys.path` - (``Lib``, ``plat-win``, etc) are based on that folder. Otherwise, the core - Python path is constructed from the PythonPath stored in the registry. - -* If the Python Home cannot be located, no :envvar:`PYTHONPATH` is specified in - the environment, and no registry entries can be found, a default path with - relative entries is used (e.g. ``.\Lib;.\plat-win``, etc). - -The end result of all this is: - -* When running :file:`python.exe`, or any other .exe in the main Python - directory (either an installed version, or directly from the PCbuild - directory), the core path is deduced, and the core paths in the registry are - ignored. Other "application paths" in the registry are always read. - -* When Python is hosted in another .exe (different directory, embedded via COM, - etc), the "Python Home" will not be deduced, so the core path from the - registry is used. Other "application paths" in the registry are always read. - -* If Python can't find its home and there is no registry (eg, frozen .exe, some - very strange installation setup) you get a path with some default, but - relative, paths. - - -Executing scripts ------------------ - -As of Python 3.3, Python includes a launcher which facilitates running Python -scripts. See :ref:`launcher` for more information. - -Executing scripts without the Python launcher ---------------------------------------------- - -Without the Python launcher installed, 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 ``.py`` scripts:: - - assoc .py=Python.File - -#. Redirect all Python files to the new executable:: - - ftype Python.File=C:\Path\to\pythonw.exe "%1" %* +installer, select Modify, and enable it. Alternatively, you can manually +modify the :envvar:`PATH` using the directions in :ref:`setting-envvars`. You +need to set your :envvar:`PATH` environment variable to include the directory +of your Python installation, delimited by a semicolon from other entries. An +example variable could look like this (assuming the first two entries already +existed):: + C:\WINDOWS\system32;C:\WINDOWS;C:\Program Files\Python 3.5 .. _launcher: @@ -251,21 +377,26 @@ Python Launcher for Windows .. versionadded:: 3.3 -The Python launcher for Windows is a utility which aids in the location and -execution of different Python versions. It allows scripts (or the +The Python launcher for Windows is a utility which aids in locating and +executing of different Python versions. It allows scripts (or the command-line) to indicate a preference for a specific Python version, and will locate and execute that version. +Unlike the :envvar:`PATH` variable, the launcher will correctly select the most +appropriate version of Python. It will prefer per-user installations over +system-wide ones, and orders by language version rather than using the most +recently installed version. + Getting started --------------- From the command-line ^^^^^^^^^^^^^^^^^^^^^ -You should ensure the launcher is on your PATH - depending on how it was -installed it may already be there, but check just in case it is not. - -From a command-prompt, execute the following command: +System-wide installations of Python 3.3 and later will put the launcher on your +:envvar:`PATH`. The launcher is compatible with all available versions of +Python, so it does not matter which version is installed. To check that the +launcher is available, execute the following command in Command Prompt: :: @@ -291,6 +422,28 @@ If you have a Python 3.x installed, try the command: You should find the latest version of Python 3.x starts. +If you see the following error, you do not have the launcher installed: + +:: + + 'py' is not recognized as an internal or external command, + operable program or batch file. + +Per-user installations of Python do not add the launcher to :envvar:`PATH` +unless the option was selected on installation. + +Virtual environments +^^^^^^^^^^^^^^^^^^^^ + +.. versionadded:: 3.5 + +If the launcher is run with no explicit Python version specification, and a +virtual environment (created with the standard library :mod:`venv` module or +the external ``virtualenv`` tool) active, the launcher will run the virtual +environment's interpreter rather than the global one. To run the global +interpreter, either deactivate the virtual environment, or explicitly specify +the global Python version. + From a script ^^^^^^^^^^^^^ @@ -326,7 +479,7 @@ From file associations ^^^^^^^^^^^^^^^^^^^^^^ The launcher should have been associated with Python files (i.e. ``.py``, -``.pyw``, ``.pyc``, ``.pyo`` files) when it was installed. This means that +``.pyw``, ``.pyc`` files) when it was installed. This means that when you double-click on one of these files from Windows explorer the launcher will be used, and therefore you can use the same facilities described above to have the script specify the version which should be used. @@ -365,6 +518,16 @@ be used by the launcher without modification. If you are writing a new script on Windows which you hope will be useful on Unix, you should use one of the shebang lines starting with ``/usr``. +Any of the above virtual commands can be suffixed with an explicit version +(either just the major version, or the major and minor version) - for example +``/usr/bin/python2.7`` - which will cause that specific version to be located +and used. + +The ``/usr/bin/env`` form of shebang line has one further special property. +Before looking for installed Python interpreters, this form will search the +executable :envvar:`PATH` for a Python executable. This corresponds to the +behaviour of the Unix ``env`` program, which performs a :envvar:`PATH` search. + Arguments in shebang lines -------------------------- @@ -383,17 +546,16 @@ Customization Customization via INI files ^^^^^^^^^^^^^^^^^^^^^^^^^^^ - Two .ini files will be searched by the launcher - ``py.ini`` in the - current user's "application data" directory (i.e. the directory returned - by calling the Windows function SHGetFolderPath with CSIDL_LOCAL_APPDATA) - and ``py.ini`` in the same directory as the launcher. The same .ini - files are used for both the 'console' version of the launcher (i.e. - py.exe) and for the 'windows' version (i.e. pyw.exe) +Two .ini files will be searched by the launcher - ``py.ini`` in the current +user's "application data" directory (i.e. the directory returned by calling the +Windows function SHGetFolderPath with CSIDL_LOCAL_APPDATA) and ``py.ini`` in the +same directory as the launcher. The same .ini files are used for both the +'console' version of the launcher (i.e. py.exe) and for the 'windows' version +(i.e. pyw.exe) - Customization specified in the "application directory" will have - precedence over the one next to the executable, so a user, who may not - have write access to the .ini file next to the launcher, can override - commands in that global .ini file) +Customization specified in the "application directory" will have precedence over +the one next to the executable, so a user, who may not have write access to the +.ini file next to the launcher, can override commands in that global .ini file) Customizing default Python versions ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ @@ -488,6 +650,99 @@ particular version was chosen and the exact command-line used to execute the target Python. + +.. finding_modules: + +Finding modules +=============== + +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\\`. + +This is how :data:`sys.path` is populated on Windows: + +* An empty entry is added at the start, which corresponds to the current + directory. + +* If the environment variable :envvar:`PYTHONPATH` exists, as described in + :ref:`using-on-envvars`, its entries are added next. Note that on Windows, + paths in this variable must be separated by semicolons, to distinguish them + from the colon used in drive identifiers (``C:\`` etc.). + +* Additional "application paths" can be added in the registry as subkeys of + :samp:`\\SOFTWARE\\Python\\PythonCore\\{version}\\PythonPath` under both the + ``HKEY_CURRENT_USER`` and ``HKEY_LOCAL_MACHINE`` hives. Subkeys which have + semicolon-delimited path strings as their default value will cause each path + to be added to :data:`sys.path`. (Note that all known installers only use + HKLM, so HKCU is typically empty.) + +* If the environment variable :envvar:`PYTHONHOME` is set, it is assumed as + "Python Home". Otherwise, the path of the main Python executable is used to + locate a "landmark file" (``Lib\os.py``) to deduce the "Python Home". If a + Python home is found, the relevant sub-directories added to :data:`sys.path` + (``Lib``, ``plat-win``, etc) are based on that folder. Otherwise, the core + Python path is constructed from the PythonPath stored in the registry. + +* If the Python Home cannot be located, no :envvar:`PYTHONPATH` is specified in + the environment, and no registry entries can be found, a default path with + relative entries is used (e.g. ``.\Lib;.\plat-win``, etc). + +If a ``pyvenv.cfg`` file is found alongside the main executable or in the +directory one level above the executable, the following variations apply: + +* If ``home`` is an absolute path and :envvar:`PYTHONHOME` is not set, this + path is used instead of the path to the main executable when deducing the + home location. + +* If ``applocal`` is set to true, the ``home`` property or the main executable + is always used as the home path, and all environment variables or registry + values affecting the path are ignored. The landmark file is not checked. + +The end result of all this is: + +* When running :file:`python.exe`, or any other .exe in the main Python + directory (either an installed version, or directly from the PCbuild + directory), the core path is deduced, and the core paths in the registry are + ignored. Other "application paths" in the registry are always read. + +* When Python is hosted in another .exe (different directory, embedded via COM, + etc), the "Python Home" will not be deduced, so the core path from the + registry is used. Other "application paths" in the registry are always read. + +* If Python can't find its home and there are no registry value (frozen .exe, + some very strange installation setup) you get a path with some default, but + relative, paths. + +For those who want to bundle Python into their application or distribution, the +following advice will prevent conflicts with other installations: + +* Include a ``pyvenv.cfg`` file alongside your executable containing + ``applocal = true``. This will ensure that your own directory will be used to + resolve paths even if you have included the standard library in a ZIP file. + It will also ignore user site-packages and other paths listed in the + registry. + +* If you are loading :file:`python3.dll` or :file:`python35.dll` in your own + executable, explicitly call :c:func:`Py_SetPath` or (at least) + :c:func:`Py_SetProgramName` before :c:func:`Py_Initialize`. + +* Clear and/or overwrite :envvar:`PYTHONPATH` and set :envvar:`PYTHONHOME` + before launching :file:`python.exe` from your application. + +* If you cannot use the previous suggestions (for example, you are a + distribution that allows people to run :file:`python.exe` directly), ensure + that the landmark file (:file:`Lib\\os.py`) exists in your install directory. + (Note that it will not be detected inside a ZIP file.) + +These will ensure that the files in a system-wide installation will not take +precedence over the copy of the standard library bundled with your application. +Otherwise, your users may experience problems using your application. Note that +the first suggestion is the best, as the other may still be susceptible to +non-standard paths in the registry and user site-packages. + Additional modules ================== @@ -498,7 +753,6 @@ and external, and snippets exist to use these features. The Windows-specific standard modules are documented in :ref:`mswin-specific-services`. - PyWin32 ------- @@ -557,20 +811,8 @@ latest release's source or just grab a fresh `checkout <https://docs.python.org/devguide/setup.html#getting-the-source-code>`_. The source tree contains a build solution and project files for Microsoft -Visual C++, which is the compiler used to build the official Python releases. -View the :file:`readme.txt` in their respective directories: - -+--------------------+--------------+-----------------------+ -| Directory | MSVC version | Visual Studio version | -+====================+==============+=======================+ -| :file:`PC/VS9.0/` | 9.0 | 2008 | -+--------------------+--------------+-----------------------+ -| :file:`PCbuild/` | 10.0 | 2010 | -+--------------------+--------------+-----------------------+ - -Note that any build directories within the :file:`PC` directory are not -necessarily fully supported. The :file:`PCbuild` directory contains the files -for the compiler used to build the official release. +Visual Studio 2015, which is the compiler used to build the official Python +releases. These files are in the :file:`PCbuild` directory. Check :file:`PCbuild/readme.txt` for general information on the build process. @@ -588,6 +830,83 @@ For extension modules, consult :ref:`building-on-windows`. by Trent Apted et al, 2007 +Embedded Distribution +===================== + +.. versionadded:: 3.5 + +The embedded distribution is a ZIP file containing a minimal Python environment. +It is intended for acting as part of another application, rather than being +directly accessed by end-users. + +When extracted, the embedded distribution is (almost) fully isolated from the +user's system, including environment variables, system registry settings, and +installed packages. The standard library is included as pre-compiled and +optimized ``.pyc`` files in a ZIP, and ``python3.dll``, ``python35.dll``, +``python.exe`` and ``pythonw.exe`` are all provided. Tcl/tk (including all +dependants, such as Idle), pip and the Python documentation are not included. + +.. note:: + + The embedded distribution does not include the `Microsoft C Runtime + <http://www.microsoft.com/en-us/download/details.aspx?id=48145>`_ and it is + the responsibility of the application installer to provide this. The + runtime may have already been installed on a user's system previously or + automatically via Windows Update, and can be detected by finding + ``ucrtbase.dll`` in the system directory. + +Third-party packages should be installed by the application installer alongside +the embedded distribution. Using pip to manage dependencies as for a regular +Python installation is not supported with this distribution, though with some +care it may be possible to include and use pip for automatic updates. In +general, third-party packages should be treated as part of the application +("vendoring") so that the developer can ensure compatibility with newer +versions before providing updates to users. + +The two recommended use cases for this distribution are described below. + +Python Application +------------------ + +An application written in Python does not necessarily require users to be aware +of that fact. The embedded distribution may be used in this case to include a +private version of Python in an install package. Depending on how transparent it +should be (or conversely, how professional it should appear), there are two +options. + +Using a specialized executable as a launcher requires some coding, but provides +the most transparent experience for users. With a customized launcher, there are +no obvious indications that the program is running on Python: icons can be +customized, company and version information can be specified, and file +associations behave properly. In most cases, a custom launcher should simply be +able to call ``Py_Main`` with a hard-coded command line. + +The simpler approach is to provide a batch file or generated shortcut that +directly calls the ``python.exe`` or ``pythonw.exe`` with the required +command-line arguments. In this case, the application will appear to be Python +and not its actual name, and users may have trouble distinguishing it from other +running Python processes or file associations. + +With the latter approach, packages should be installed as directories alongside +the Python executable to ensure they are available on the path. With the +specialized launcher, packages can be located in other locations as there is an +opportunity to specify the search path before launching the application. + +Embedding Python +---------------- + +Applications written in native code often require some form of scripting +language, and the embedded Python distribution can be used for this purpose. In +general, the majority of the application is in native code, and some part will +either invoke ``python.exe`` or directly use ``python3.dll``. For either case, +extracting the embedded distribution to a subdirectory of the application +installation is sufficient to provide a loadable Python interpreter. + +As with the application use, packages can be installed to any location as there +is an opportunity to specify search paths before initializing the interpreter. +Otherwise, there is no fundamental differences between using the embedded +distribution and a regular installation. + Other resources =============== @@ -603,5 +922,3 @@ Other resources :pep:`397` - Python launcher for Windows The proposal for the launcher to be included in the Python distribution. - - |