lem-evdev

About

lem-evdev is a library for the Lua Event Machine which allows you to get events from Linux event devices without blocking the main loop.

The Linux event devices are usually located under /dev/input/event<n>, and can be used to get raw input events from keyboards, mice, joysticks, as well the lid switch, special keys and accelerometer on many laptops.

Installation

Get the source and do

make
make install

This installs the library under /usr/local/lib/lua/5.1/. Use

make PREFIX=<your custom path> install

to install to <your custom path>/lib/lua/5.1/.

Usage

Import the module using something like

local evdev = require 'lem.evdev'

This sets evdev to a table with the following functions.

• evdev.open(path)

  Opens the event device at the given path and returns a new device object.

  Returns nil followed by an error message on error.

The metatable of device objects can be found under evdev.Device.

The following methods are available on devices.

• dev:close()

  Closes the device. If the device is busy, this also interrupts the IO action on the device.

  Returns true on succes or otherwise nil followed by an error message. If the device is already closed the error message will be 'already closed'.

• dev:interrupt()

  Interrupt any coroutine waiting for IO on the device.

  Returns true on success and nil, 'not busy' if no coroutine is waiting for IO on the device.

• dev:get()

  Get the next event from the device. On success this method will return 4 values:

  • type: a string describing the event type.
  • code: the event code.
  • value: a value associated to the event.
  • timestamp: a unix timestamp in seconds, but with microsecond resolution.

  If there are no unread events the current coroutine will be suspended until there is.

  Returns nil followed by an error message on error. If another coroutine is waiting for IO on the device the error message will be 'busy'. If the device was interrupted (eg. by another coroutine calling dev:interrupt(), or dev:close()) the error message will be 'interrupted'. If the device was closed the error message will be 'closed'.

License

lem-evdev is free software. It is distributed under the terms of the GNU General Public License.

Contact

Please send bug reports, patches, feature requests, praise and general gossip to me, Emil Renner Berthing esmil@mailme.dk.