LibUEvent - A Microscopic event library.

The libuevent library is a small event library in the style of the venerable Xt(3) event loop.

Basically an event context is created,and handlers for timeounts and stream events can be registered with this context.

After initial setup, the typical application will enter the event loop that will only return at program termination.

The C API

The typical application will do the following steps

1. Create the event context with lueCtxtCreate()
2. Register initial callbacks with lueAddInput, lueAddOutput and lueAddTimer
3. Enter the event loop

Lua binding

A lua binding is available that should mix well with luasocket and luaposix. Time resolutions are in milli second integers in order to support integer-only embedded environments

function luevent.addFileIO(fdesc, handler, mode)

Add a handler on a stream. The handler will sustain itself GC wise. Use object:clear() to unregister the handler

• fdesc The posix file descriptor "small integer".
  Use the ":getfd()" method on a "normal" lua stream or socket to obtain fdesc.
• handler A function object. The handler object is supplied as the first parameter when called.
• mode Optional. Input ("r") or output ("w") event. Default is input
• return A new filehandler object

function luevent.addTimer(msecs, handler)

Create a new timer object. Implicitly cleared when handler is called. Typical usage:

  local hdl
  hdl = luevent.addTimer(50, function() hdl = nil ..... end)
  ......
  if hdl then hdl:clear() hdl = nil end

Here hdl is used to keep track of whether the timer is active.

• msecs The number of milliseconds until the timer expires
• handler A function object. The handler object is supplied as the first parameter when called.
• return A new timer object

function object:clear()

Cancel a callback registration. Renders the object ready for GC.

function object:handler()

Obtain the handler function from a callback registration.

Building

Use make:

• make all: The library
• make test: Test and showcase
• make lua: Build the lua binding

Installation

Is purely manual, but would be something along the lines of:

   sudo install -m 444 libuevent.so.1 /usr/lib/libuevent.so.1
   sudo install -m 444 luevent.so /usr/lib/lua/5.1/luevent.so