XkbAllocDeviceLedInfo allocates space for an XkbDeviceLedInfoRec and places it in device_info. If num_needed is nonzero, num_needed XkbIndicatorMapRec structures are also allocated and linked into the XkbDeviceLedInfoRec structure. If you request XkbIndicatorMapRec structures be allocated using this request, you must initialize them explicitly. All other fields are initialized to zero.
To initialize an XkbDeviceLedInfoRec structure, use XkbAddDeviceLedInfo.
Information about X Input Extension devices is transferred between
a client program and the Xkb extension in an XkbDeviceInfoRec structure:
typedef struct {
char * name; /* name for device */
Atom type; /* name for class of devices
*/
unsigned short device_spec; /* device of interest */
Bool has_own_state; /* True=>this device has its
own state */
unsigned short supported; /* bits indicating supported
capabilities */
unsigned short unsupported; /* bits indicating unsupported
capabilities */
unsigned short num_btns; /* number of entries in btn_acts
*/
XkbAction * btn_acts; /* button actions */
unsigned short sz_leds; /* total number of entries
in LEDs vector */
unsigned short num_leds; /* number of valid entries
in LEDs vector */
unsigned short dflt_kbd_fb; /* input extension ID of default
(core kbd) indicator */
unsigned short dflt_led_fb; /* input extension ID of default
indicator feedback */
XkbDeviceLedInfoPtr leds; /* LED descriptions */
} XkbDeviceInfoRec, *XkbDeviceInfoPtr;
typedef struct {
unsigned short led_class; /* class for this LED device*/
unsigned short led_id; /* ID for this LED device
*/
unsigned int phys_indicators; /* bits for which LEDs physically
present */
unsigned int maps_present; /* bits for which LEDs have
maps in maps */
unsigned int names_present; /* bits for which LEDs are
in names */
unsigned int state; /* 1 bit => corresponding
LED is on */
Atom names[XkbNumIndicators]; /* names for LEDs
*/
XkbIndicatorMapRec maps; /* indicator maps for each
LED */
} XkbDeviceLedInfoRec, *XkbDeviceLedInfoPtr;
Each indicator has its own set of attributes that specify whether clients
can explicitly set its state and whether it tracks the keyboard state. The
attributes of each indicator are held in the maps array, which is an array
of XkbIndicatorRec structures: typedef struct {
unsigned char flags; /* how the indicator can be changed
*/
unsigned char which_groups; /* match criteria for groups
*/
unsigned char groups; /* which keyboard groups the
indicator watches */
unsigned char which_mods; /* match criteria for modifiers
*/
XkbModsRec mods; /* which modifiers the indicator
watches */
unsigned int ctrls; /* which controls the indicator
watches */
} XkbIndicatorMapRec, *XkbIndicatorMapPtr;
This indicator map specifies for each indicator: