Like most of liblx's facilities, events are handled through callbacks.

Evern LX_CONN has an event handler, which is a callback provided by the
application.  When the library receives an event on the wire, it
unpacks it and calls the event handler, which then can inspect the
event and do whatever is appropriate for the application (ignore it,
use it, pass it off to other code, whatever).

LX_EVENT is a struct containing an event type field (type) and a "came
from SendEvent" flag (send_event), plus a union (u) with one arm for
each event type.  The core event types are

	ButtonPress      Expose           MappingNotify
	ButtonRelease    FocusIn          MotionNotify
	CirculateNotify  FocusOut         NoExposure
	CirculateRequest GraphicsExposure PropertyNotify
	ClientMessage    GravityNotify    ReparentNotify
	ColormapNotify   KeyPress         ResizeRequest
	ConfigureNotify  KeyRelease       SelectionClear
	ConfigureRequest KeymapNotify     SelectionNotify
	CreateNotify     LeaveNotify      SelectionRequest
	DestroyNotify    MapNotify        UnmapNotify
	EnterNotify      MapRequest       VisibilityNotify

Each of these has a value LX_EV_(name) and an event-specific struct
LX_EVENT_(name); the union field for each event type is the event type
name.  For example, for ButtonPress events events, type is set to
LX_EV_ButtonPress and the LX_EVENT's .u.ButtonPress is an
LX_EVENT_ButtonPress struct containing the ButtonPress-specific fields.

Note that event handler callbacks must be prepared to deal with
unexpected events  Some events are sent by the server with no way for
the client to express lack of interest (MappingNotify is an example);
also, SendEvent can be used to send an arbitrary event to any client
which either has created a window or has keyboard focus.

For example, if an application wants to exit upon receiving any
ButtonPress event on a window whose ID is in a variable `quitwin' (this
might be a user-interface "quit" button), its event handler could
contain code like

	void event_handler(LX_CONN *conn, const LX_EVENT *ev)
	{
		switch (ev->type)
		{
...
			case LX_EV_ButtonPress:
				if (ev->u.ButtonPress.eventw == quitwin)
					exit(0);
...
		}
	}

See extensions.txt for how extension events are handled.