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15. Optional Operating System Services

The modules described in this chapter provide interfaces to operating system features that are available on selected operating systems only. The interfaces are generally modeled after the Unix or C interfaces but they are available on some other systems as well (e.g. Windows or NT). Here's an overview:

`select` |  | Wait for I/O completion on multiple streams.
`thread` |  | Create multiple threads of control within one interpreter.
`threading` |  | Higher-level threading interface.
`dummy_thread` |  | Drop-in replacement for the `thread` module.
`dummy_threading` |  | Drop-in replacement for the `threading` module.
`mmap` |  | Interface to memory-mapped files for Unix and Windows.
`readline` |  | GNU readline support for Python.
`rlcompleter` |  | Python identifier completion, suitable for the GNU readline library.