giiEventSend injects an event into the queue. Such events can be identified by (event->any.origin == GII_EV_ORIGIN_SENDEVENT). There are three main uses for this function:
"Simulating" input for independent subprograms.
Sending events to externally attached programs via specialized "inputs", that are actually rather "outputs".
Sending command events to inputs, like querying the axis of a valuator device.