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" --- Waiting for I/O completion

  * Edge and Level Trigger Polling (epoll) Objects

  * Polling Objects

  * Kqueue Objects

  * Kevent Objects

* "threading" --- Higher-level threading interface

  * Thread Objects

  * Lock Objects

  * RLock Objects

  * Condition Objects

  * Semaphore Objects

    * "Semaphore" Example

  * Event Objects

  * Timer Objects

  * Using locks, conditions, and semaphores in the "with" statement

  * Importing in threaded code

* "thread" --- Multiple threads of control

* "dummy_threading" --- Drop-in replacement for the "threading"
  module

* "dummy_thread" --- Drop-in replacement for the "thread" module

* "multiprocessing" --- Process-based "threading" interface

  * Introduction

    * The "Process" class

    * Exchanging objects between processes

    * Synchronization between processes

    * Sharing state between processes

    * Using a pool of workers

  * Reference

    * "Process" and exceptions

    * Pipes and Queues

    * Miscellaneous

    * Connection Objects

    * Synchronization primitives

    * Shared "ctypes" Objects

      * The "multiprocessing.sharedctypes" module

    * Managers

      * Namespace objects

      * Customized managers

      * Using a remote manager

    * Proxy Objects

      * Cleanup

    * Process Pools

    * Listeners and Clients

      * Address Formats

    * Authentication keys

    * Logging

    * The "multiprocessing.dummy" module

  * Programming guidelines

    * All platforms

    * Windows

  * Examples

* "mmap" --- Memory-mapped file support

* "readline" --- GNU readline interface

  * Example

* "rlcompleter" --- Completion function for GNU readline

  * Completer Objects