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XkbAddDeviceLedInfo - Initialize an XkbDeviceLedInfoRec structure


XkbDeviceLedInfoPtr XkbAddDeviceLedInfo
(XkbDeviceInfoPtr device_info, unsigned int led_class, unsigned int led_id);


- device_info
structure in which to add LED info
- led_class
input extension class for LED device of interest
- led_id
input extension ID for LED device of interest


XkbAddDeviceLedInfo first checks to see whether an entry matching led_class and led_id already exists in the device_info->leds array. If it finds a matching entry, it returns a pointer to that entry. Otherwise, it checks to be sure there is at least one empty entry in device_info->leds and extends it if there is not enough room. It then increments device_info->num_leds and fills in the next available entry in device_info->leds with led_class and led_id.

If successful, XkbAddDeviceLedInfo returns a pointer to the XkbDeviceLedInfoRec structure that was initialized. If unable to allocate sufficient storage, or if device_info points to an invalid XkbDeviceInfoRec structure, or if led_class or led_id are inappropriate, XkbAddDeviceLedInfo returns NULL.

To allocate additional space for button actions in an XkbDeviceInfoRec structure, use XkbResizeDeviceButtonActions.


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;

See Also


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