# 2.5 `MacOS` -- Access to Mac OS interpreter features

Availability: Macintosh.

This module provides access to MacOS specific functionality in the Python interpreter, such as how the interpreter eventloop functions and the like. Use with care.

Note the capitalization of the module name; this is a historical artifact.

`runtimemodel`
  Either`'carbon'` or `'macho'`. This signifies whether this Python uses the Mac OS X and Mac OS 9 compatible CarbonLib style or the Mac OS X-only Mach-O style. In earlier versions of Python the value could also be `'ppc'` for the classic Mac OS 8 runtime model.

`linkmodel`
  The way the interpreter has been linked. As extension modules may be incompatible between linking models, packages could use this information to give more decent error messages. The value is one of `'static'` for a statically linked Python, `'framework'` for Python in a Mac OS X framework, `'shared'` for Python in a standard unix shared library and `'cfm'` for the Mac OS 9-compatible Python.

exception `Error`
  This exception is raised on MacOS generated errors, either from functions in this module or from other mac-specific modules like the toolbox interfaces. The arguments are the integer error code (the `OSErr` value) and a textual description of the error code. Symbolic names for all known error codes are defined in the standard module `macerrors`.

`SetEventHandler`( | handler)

  In the inner interpreter loop Python will occasionally check for events, unless disabled with `ScheduleParams()`. With this function you can pass a Python event-handler function that will be called if an event is available. The event is passed as parameter and the function should return non-zero if the event has been fully processed, otherwise event processing continues (by passing the event to the console window package, for instance).

  Call `SetEventHandler()` without a parameter to clear the event handler. Setting an event handler while one is already set is an error.

  Availability: MacPython-OS9.

`SchedParams`( | [doint[, evtmask[, besocial[, interval[, bgyield]]]]])

  Influence the interpreter inner loop event handling. Interval specifies how often (in seconds, floating point) the interpreter should enter the event processing code. When true, doint causes interrupt (command-dot) checking to be done. evtmask tells the interpreter to do event processing for events in the mask (redraws, mouseclicks to switch to other applications, etc). The besocial flag gives other processes a chance to run. They are granted minimal runtime when Python is in the foreground and bgyield seconds per interval when Python runs in the background.

  All parameters are optional, and default to the current value. The return value of this function is a tuple with the old values of these options. Initial defaults are that all processing is enabled, checking is done every quarter second and the processor is given up for a quarter second when in the background.

  The most common use case is to call `SchedParams(0, 0)` to completely disable event handling in the interpreter mainloop.

  Availability: MacPython-OS9.

`HandleEvent`( | ev)

  Pass the event record ev back to the Python event loop, or possibly to the handler for the `sys.stdout` window (based on the compiler used to build Python). This allows Python programs that do their own event handling to still have some command-period and window-switching capability.

  If you attempt to call this function from an event handler set through `SetEventHandler()` you will get an exception.

  Availability: MacPython-OS9.

`GetErrorString`( | errno)

  Return the textual description of MacOS error code errno.

`splash`( | resid)

  This function will put a splash window on-screen, with the contents of the DLOG resource specified by resid. Calling with a zero argument will remove the splash screen. This function is useful if you want an applet to post a splash screen early in initialization without first having to load numerous extension modules.

  Availability: MacPython-OS9.

`DebugStr`( | message [, object])

  On Mac OS 9, drop to the low-level debugger with message message. The optional object argument is not used, but can easily be inspected from the debugger. On Mac OS X the string is simply printed to stderr.

  Note that you should use this function with extreme care: if no low-level debugger like MacsBug is installed this call will crash your system. It is intended mainly for developers of Python extension modules.

`SysBeep`( | )

  Ring the bell.

`GetTicks`( | )

  Get the number of clock ticks (1/60th of a second) since system boot.

`GetCreatorAndType`( | file)

  Return the file creator and file type as two four-character strings. The file parameter can be a pathname or an `FSSpec` or `FSRef` object.

`SetCreatorAndType`( | file, creator, type)

  Set the file creator and file type. The file parameter can be a pathname or an `FSSpec` or `FSRef` object. creator and type must be four character strings.

`openrf`( | name [, mode])

  Open the resource fork of a file. Arguments are the same as for the built-in function `open()`. The object returned has file-like semantics, but it is not a Python file object, so there may be subtle differences.

`WMAvailable`( | )

  Checks whether the current process has access to the window manager. The method will return `False` if the window manager is not available, for instance when running on Mac OS X Server or when logged in via ssh, or when the current interpreter is not running from a fullblown application bundle. A script runs from an application bundle either when it has been started with pythonw instead of python or when running as an applet.

  On Mac OS 9 the method always returns `True`.