.. _glossary:

########
Glossary
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This glossary defines terms and names commonly used throughout the Native Client
documentation.

asynchronous programming
  In the asynchronous programming model, function calls are executed and return
  immediately without waiting for a response. Using this model, function calls
  are non-blocking; the web browser continues its main thread of execution
  and gets notified of asynchronous call completion through callbacks or some
  other mechanism.
focus events
  Events that indicate whether certain parts of a web page are
  in or out of focus.
input events
  Events that occur when an input device (such as keyboard or mouse)
  is used to interact with an module instance.
instance
  A rectangle on a web page that is managed by a Native Client module (the
  rectangle can have ``width=0`` and ``height=0``, which means that nothing is
  drawn on the page).
manifest file
  A file containing metadata or information about accompanying files.
message events
  Events used to pass data between JavaScript and the Native Client
  module (see the :doc:`Messaging System <devguide/coding/message-system>` chapter).
module
  Depending on context, "module" may mean one of two things. First, it may be a
  general short-term for for "Native Client module"---compiled C/C++ code
  produced with a Native Client toolchain (for example PNaCl). See
  :ref:`link_how_nacl_works` for more details.
  Second, it may refer to a concrete implementation of the `pp::Module class
  </native-client/pepper_stable/cpp/classpp_1_1_module>`_ for some Native
  Client module.
progress events
  Events generated by the Native Client runtime system during the
  module loading process.
Var
  An object in a Native Client module that corresponds to a JavaScript
  variable.
view change events
  Events that occur when a change in the browser affects the
  module instance (such as resizing the browser window or going to
  and from fullscreen mode).
web workers
  `Web workers <http://en.wikipedia.org/wiki/Web_Workers>`_ provide a
  mechanism for running heavy-weight JavaScript code on background threads
  so that the main web page can continue to respond to user interaction.
  Web pages interact with web workers by using ``postMessage()`` to send
  messages. The way a web page interacts with a Native Client module
  is analogous to the way it interacts with web workers.