GdkEventTypetype; the type of the event (GDK_CLIENT_EVENT). GdkWindow*window; the window which received the event. gint8send_event; TRUE if the event was sent explicitly (e.g. using XSendEvent). GdkAtommessage_type; the type of the message, which can be defined by the application. gushortdata_format; the format of the data, given as the number of bits in each data element, i.e. 8, 16, or 32. 8-bit data uses the b array of the data union, 16-bit data uses the s array, and 32-bit data uses the l array.