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Python launcher for windows download
This is specified in detail later in this PEP. I want to run Python script using “Python launcher” so that I can use shebang line to specify the Python environment for each individual script. This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Python launcher for windows download
A Python launcher is a single executable which uses a number of heuristics to locate a Python executable and launch it with a specified command line. As Python 3. This is described in detail in the evecve 2 man page [1] and while user documentation will be created for this feature, fod the purposes of this PEP that man page describes a valid shebang line.
Additionally, these operating systems provide symbolic-links to Python executables in well-known directories. These symbolic links allow Python to be executed without regard for where Python it actually installed on the python launcher for windows download eg.
These 2 facilities combined allow for a portable and somewhat predictable way of both starting Python interactively and for allowing Python scripts to execute. While this PEP offers the ability to use a shebang line which should work on both Windows and Unix, this is not the primary motivation for this PEP – the primary motivation is to allow a specific version to be specified without inventing new syntax or conventions to describe it.
This PEP specifies features of the launcher; a prototype implementation is provided in [3] which will be distributed together with the Windows installer of Python, but will also be available separately but released along with the Python installer. New features may be added to the нажмите для деталей as long as the features prescribed here continue to work. The launcher is installed into the Windows directory see discussion below if installed by a privileged user.
The installation in the Windows directory is a bit executable see discussion ; the standalone installer may also offer to install bit windowe of the launcher. It contains a version resource matching the version number of the pythonXY. Python launcher for windows download installations will overwrite older version of the launcher with newer versions.
The launcher is not tied to a specific version of Python – eg. However, the launcher binaries python launcher for windows download a version resource that is the monopoly na pc download as the version resource in the Python binaries that they are released with.
The launcher is restricted to launching Python scripts. It is not intended as a general-purpose script launcher or shebang processor. The launcher supports the syntax of shebang lines as described in [1]including all restrictions listed.
This means that many scripts can use a single shebang line and be likely to work on both Unix and Windows without modification. The launcher will support fully-qualified paths to executables.
While this will make the script inherently non-portable, it is a feature offered by Unix and would be useful for Windows users in some cases. Scripts taking advantage of this will not be portable as these customization options must be set to reflect iwndows configuration of the machine on which the launcher is running but вот ссылка ability is nonetheless considered worthwhile.
As the launcher on Windows will not use Windows links, customization options exposed via both environment variables and INI files will be used to override the semantics for determining what version of Python will be used. This is specified in detail later in this PEP. However, if a valid shebang line is found but the process specified by that line can not be started, the default interpreter will not be started – the error to create the specified child launcber will cause the launcher to display an appropriate message and python launcher for windows download with a specific exit code.
The same. The command executed is based diwnload the rules described in Python Version Qualifiers below. The precise details about the names, locations and search order of the. On 64bit Windows with both 32bit and 64bit implementations of wndows same major. This will be true for both 32bit and 64bit implementations of the launcher – a python launcher for windows download launcher will prefer python launcher for windows download execute a 64bit Need speed underground pc download completo installation of the specified version if available.
This is so the behavior of the launcher can be predicted knowing only what versions are installed on the PC and without regard to the luancher in which they were installed ie, without knowing whether a 32 or 64bit lanucher of Python and corresponding launcher was installed last. Note this value could specify just a major version e. If no such option is found, the launcher will enumerate the installed Python versions and use the downloav minor release found for the major version, which is likely, although not guaranteed, to be the most recently installed version in that family.
In python launcher for windows download to python launcher for windows download variables, the same pythob can be configured in the. INI file used by the launcher. The contents of an environment variable will override things specified in the INI file. This will cause help for the launcher being printed followed by help for Python itself. The output from the launcher will clearly indicate the extended help information is coming from the launcher and not Python.
If a Python 2. Note that this feature can not be used with shebang processing as the file scanned for a shebang line and this argument python launcher for windows download both be the first argument and therefore are mutually exclusive.
The launcher offers some conveniences for Python developers working interactively – for example, starting the launcher with no command-line arguments will launch the default Python with no command-line arguments. Further, command-line arguments will be supported to allow a specific Python version to be launched interactively – however, these conveniences must not detract from the primary purpose of launching lwuncher and must be easy to avoid if desired. The launcher creates a subprocess to start the actual interpreter.
See Discussion below for the rationale. It may be surprising that the launcher is installed into the Windows directory, and not the System32 directory. The reason is that the System32 dosnload is not on the Path of a bit process running on a bit system.
However, the Python launcher for windows download directory is always on the path. The launcher that is installed into the Windows directory is a bit executable so that the bit CPython installer can provide the same binary for both bit and bit Windows installations.
Ideally, the launcher process would execute Python directly inside the same process, primarily so the parent of the launcher process could terminate the launcher увидеть больше have the Python interpreter terminate.
If the launcher executes Python as a продолжение здесь and the parent of the launcher terminates больше на странице launcher, the Python process will be unaffected.
However, there are a number of practical problems associated with this approach. The most serious side effect of this is that the value of sys. Many Python scripts use the value of sys. If sys. The final hurdle is the rules above regarding 64bit and 32bit programs – a 32bit launcher would be unable to load the 64bit version of Python and vice-versa. Given these considerations, the launcher will execute its command in a child process, remaining alive while the child process is executing, then terminate with the same exit code as returned by the child.
To address concerns regarding the termination of the launcher not killing the child, the Win32 Job API will be used to arrange so that the child process python launcher for windows download automatically killed when the parent is terminated although children of that child process will continue as is the case now.
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