gdk-event-source-device (event)

event -- a gdk-event instance
device -- a gdk-device object

Accessor of the slave device for the event.

The function gdk-event-source-device returns the hardware (slave) device that has triggered the event, falling back to the virtual (master) device, as in the function gdk-event-device, if the event was not caused by interaction with a hardware device. The function (setf gdk-event-source-device) sets the slave device for the event.

This may happen for example in synthesized crossing events after a gdk-window object updates its geometry or a grab is acquired/released.

If the event does not contain a device field, this function will return nil.

The event must have been allocated by GTK, for instance by the function gdk-event-copy.