XkbAllocDeviceInfo allocates space for an XkbDeviceInfoRec structure and initializes that structure's device_spec field with the device ID specified by device_spec. If n_buttons is nonzero, n_buttons XkbActions are linked into the XkbDeviceInfoRec structure and initialized to zero. If sz_leds is nonzero, sz_leds XkbDeviceLedInfoRec structures are also allocated and linked into the XkbDeviceInfoRec structure. If you request XkbDeviceLedInfoRec structures be allocated using this request, you must initialize them explicitly.
To obtain an XkbDeviceLedInfoRec structure, use XkbAllocDeviceLedInfo.
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;