To determine whether the X server allows Xkb access to particular capabilities of input devices other than the core X keyboard, or to determine the status of indicator maps, indicator names or button actions on a non-KeyClass extension device, use XkbGetDeviceInfo.
XkbGetDeviceInfo returns information about the input device specified by device_spec. Unlike the device_spec parameter of most Xkb functions, device_spec does not need to be a keyboard device. It must, however, indicate either the core keyboard or a valid X Input Extension device.
The which parameter is a mask specifying optional information to be returned. It is an inclusive OR of one or more of the values from Table 1 and causes the returned XkbDeviceInfoRec to contain values for the corresponding fields specified in the table.
Table 1 XkbDeviceInfoRec Mask Bits
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Name XkbDeviceInfoRec Value Capability If Set
Fields Effected
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XkbXI_KeyboardsMask (1L <<0) Clients can use all
Xkb requests and events
with KeyClass devices
supported by the input
device extension.
XkbXI_ButtonActionsMask num_btns (1L <<1) Clients can assign key
btn_acts actions to buttons
non-KeyClass input
extension devices.
XkbXI_IndicatorNamesMask leds->names (1L <<2) Clients can assign
names to indicators on
non-KeyClass input
extension devices.
XkbXI_IndicatorMapsMask leds->maps (1L <<3) Clients can assign
indicator maps to
indicators on
non-KeyClass input
extension devices.
XkbXI_IndicatorStateMask leds->state (1L <<4) Clients can request
the status of indicators
on non-KeyClass input
extension devices.
XkbXI_IndicatorsMask sz_leds (0x1c) XkbXI_IndicatorNamesMask |
num_leds XkbXI_IndicatorMapsMask |
leds->* XkbXI_IndicatorStateMask
XkbXI_UnsupportedFeaturesMask unsupported (1L <<15)
XkbXI_AllDeviceFeaturesMask Those selected (0x1e) XkbXI_IndicatorsMask |
by Value Column XkbSI_ButtonActionsMask
masks
XkbXI_AllFeaturesMask Those selected (0x1f) XkbSI_AllDeviceFeaturesMask |
by Value Column XkbSI_KeyboardsMask
masks
XkbXI_AllDetailsMask Those selected (0x801f) XkbXI_AllFeaturesMask |
by Value column XkbXI_UnsupportedFeaturesMask
masks
The XkbDeviceInfoRec returned by XkbGetDeviceInfo always has values for name (may be a null string, ""), type, supported, unsupported, has_own_state, dflt_kbd_fd, and dflt_kbd_fb. Other fields are filled in as specified by which.
Upon return, the supported field will be set to the inclusive OR of zero or more bits from Table 1; each bit set indicates an optional Xkb extension device feature supported by the server implementation, and a client may modify the associated behavior.
If the XkbButtonActionsMask bit is set in which, the XkbDeviceInfoRec returned will have the button actions (btn_acts field) filled in for all buttons.
If which includes one of the bits in XkbXI_IndicatorsMask, the feedback class of the indicators must be specified in ind_class, and the feedback ID of the indicators must be specified in ind_id. If the request does not include any of the bits in XkbXI_IndicatorsMask, the ind_class and ind_id parameters are ignored. The class and ID can be obtained via the input device extension XListInputDevices request.
If any of the XkbXI_IndicatorsMask bits are set in which, the XkbDeviceInfoRec returned will have filled in the portions of the leds structure corresponding to the indicator feedback identified by ind_class and ind_id. The leds vector of the XkbDeviceInfoRec is allocated if necessary and sz_leds and num_leds filled in. The led_class, led_id and phys_indicators fields of the leds entry corresponding to ind_class and ind_id are always filled in. If which contains XkbXI_IndicatorNamesMask, the names_present and names fields of the leds structure corresponding to ind_class and ind_id are returned. If which contains XkbXI_IndicatorStateMask, the corresponding state field is updated. If which contains XkbXI_IndicatorMapsMask, the maps_present and maps fields are updated.
Xkb provides convenience functions to request subsets of the information available via XkbGetDeviceInfo. These convenience functions mirror some of the mask bits. The functions all take an XkbDeviceInfoPtr as an input argument and operate on the X Input Extension device specified by the device_spec field of the structure. Only the parts of the structure indicated in the function description are updated. The XkbDeviceInfoRec structure used in the function call can be obtained by calling XkbGetDeviceInfo or can be allocated by calling XkbAllocDeviceInfo.
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;