The purpose of DILL is to provide joystick device information, including:

• device addition and removal
• device specification
• change in device state

This information is exposed via a simple C style API such that other languages, such as Python, can easily interface with it. The desired information is obtained from the DirectInput system as well as Windows' event system.

The main way of interacting with DILL occurs via the two callbacks exposed by the library.

The set_input_event_callback function allows setting the callback responsible to inform the the using code about the addition or removal of a device. The callback has the following form void device_change_callback(DeviceSummary info, DeviceActionType action).

The set_device_change_callback is execute whenever a device changes its state and takes a callback of the following form void event_callback(JoystickInputData data).