gii_event_mask(3) LibGII event structures

Other Alias

gii_event, gii_any_event, gii_event_type


#include <ggi/events.h>
typedef union gii_event {
uint8_t size;
gii_any_event any;
gii_cmd_event cmd;
gii_expose_event expose;
gii_val_event val;
gii_key_event key;
gii_pmove_event pmove;
gii_pbutton_event pbutton;
} gii_event;
#define COMMON_DATA \
uint8_t size; /* size of event in bytes */\
uint8_t type; /* type of this event */\
int16_t error; /* error (for replies) */\
uint32_t origin; /* origin device (etc) */\
uint32_t target; /* target device (etc) */\
struct timeval time /* timestamp */
typedef struct {
} gii_any_event;


Events are of type gii_event. It is an union of all of the structures for each specific type of event.


All of the event structures contains housekeeping information at the beginning, as defined by COMMON_DATA.

Thus, by analyzing the contents of any.type, you can determine what the given event is, and select the appropriate member of the gii_event union to access to get at the event

The common fields found in any event structure are:

Specifies the size of the given event (in bytes).

An enumeration of the possible types of LibGII events (see next section).

Mainly there to round things up to a 32-bit boundary, but could be used to signal an error in a send-reply sequence.

A device handle: it distinguishes one input device from another. Other than that there's no real meaning to the number.

Also a device handle, but for distinguishes input devices when sending events to an input device via giiEventSend(3).

Indicates when the event in question has been generated. See gettimeofday(2) for more info on the timeval structure.


The different types of events are defined as an enumeration of type gii_event_type. The possible values are:
  • evNothing : event is not valid.
  • evCommand : report command or do action.
  • evInformation : notification of new information.
  • evExposure : exposure event.
  • evKeyPress : a key has been pressed.
  • evKeyRelease : a key has been released.
  • evKeyRepeat : automatically repeated keypress.
  • evPtrRelative : pointer movement reported in relative coordinates.
  • evPtrAbsolute : pointer movement reported in absolute coordinates.
  • evPtrButtonPress : a pointer button has been pressed.
  • evPtrButtonRelease : a pointer button has been released.
  • evValRelative : valuator change reported as a relative value.
  • evValAbsolute : valuator change reported as an absolute value.


gii_event_mask is passed to various event handling functions to indicate which types of events the program is interested in. The list below sums the available event masks:
  • emCommand : evCommand
  • emInformation : evInformation
  • emExpose : evExpose
  • emKeyPress : evKeyPress
  • emKeyRelease : evKeyRelease
  • emKeyRepeat : evKeyRepeat
  • emKey : Any of evKeyPress, evKeyRelease or evKeyRepeat
  • emPtrRelative : evPtrRelative
  • emPtrAbsolute : evPtrAbsolute
  • emPtrButtonPress : evPtrButtonPress
  • emButtonRelease : evButtonRelease
  • emPtrMove : Any of evPtrRelative or evPtrAbsolute
  • emPtrButton : Any of evPtrButtonPress or evPtrButtonRelease
  • emPointer : All pointer events
  • emValRelative : evValRelative
  • emValAbsolute : evValAbsolute
  • emValuator : Any of evValRelative or evValAbsolute
  • emAll : Any event type
  • emNothing : Matches no event type