path: root/specs/XIproto.txt

X11 Input Extension Protocol Specification
==========================================

                      Version 1.0
                   X Consortium Standard
                 X Version 11, Release 6.8
               Mark Patrick, Ardent Computer
               George Sachs, Hewlett-Packard

                      Version 1.5
                    Peter Hutterer

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1. Input Extension Overview
---------------------------

This document defines an extension to the X11 protocol to
support input devices other than the core X keyboard and
pointer. An accompanying document defines a corresponding
extension to Xlib (similar extensions for languages other than
C are anticipated). This first section gives an overview of the
input extension. The next section defines the new protocol
requests defined by the extension. We conclude with a
description of the new input events generated by the additional
input devices.

This document only describes the behaviour of servers supporting
up to the X Input Extension 1.5. For servers supporting the X
Input Extensions 2.0, see XI2proto.txt. New clients are discouraged
from using this protocol specification. Instead, the use of XI 2.x
is recommended.

1.1 Design Approach
~~~~~~~~~~~~~~~~~~~

The design approach of the extension is to define requests and
events analogous to the core requests and events. This allows
extension input devices to be individually distinguishable from
each other and from the core input devices. These requests and
events make use of a device identifier and support the
reporting of n-dimensional motion data as well as other data
that is not reportable via the core input events.

1.2 Core Input Devices
~~~~~~~~~~~~~~~~~~~~~~

The X server core protocol supports two input devices: a
pointer and a keyboard. The pointer device has two major
functions. First, it may be used to generate motion information
that client programs can detect. Second, it may also be used to
indicate the current location and focus of the X keyboard. To
accomplish this, the server echoes a cursor at the current
position of the X pointer. Unless the X keyboard has been
explicitly focused, this cursor also shows the current location
and focus of the X keyboard. The X keyboard is used to generate
input that client programs can detect.

In servers supporting XI 1.4 and above, the core pointer and
the core keyboard are virtual devices that do not represent a
physical device connected to the host computer.
In servers supporting XI 2.0 and above, there may be multiple
core pointers and keyboards. Refer to XI2proto.txt for more
information.

The X keyboard and X pointer are referred to in this document
as the core devices, and the input events they generate
(KeyPress, KeyRelease, ButtonPress, ButtonRelease, and
MotionNotify) are known as the core input events. All other
input devices are referred to as extension input devices and
the input events they generate are referred to as extension
input events.

In servers supporting only XI 1.x, this input extension does
not change the behavior or functionality of the core input
devices, core events, or core protocol requests, with the
exception of the core grab requests. These requests may affect
the synchronization of events from extension devices. See the
explanation in the section titled "Event Synchronization and
Core Grabs".

Selection of the physical devices to be initially used by the
server as the core devices is left implementation-dependent.
Requests are defined that allow client programs to change which
physical devices are used as the core devices.

1.3 Extension Input Devices
~~~~~~~~~~~~~~~~~~~~~~~~~~~

The input extension v1.x controls access to input devices other
than the X keyboard and X pointer. It allows client programs to
select input from these devices independently from each other
and independently from the core devices.

A client that wishes to access a specific device must first
determine whether that device is connected to the X server.
This is done through the ListInputDevices request, which will
return a list of all devices that can be opened by the X
server. A client can then open one or more of these devices
using the OpenDevice request, specify what events they are
interested in receiving, and receive and process input events
from extension devices in the same way as events from the X
keyboard and X pointer. Input events from these devices are of
extension types ( DeviceKeyPress, DeviceKeyRelease,
DeviceButtonPress, DeviceButtonRelease, DeviceMotionNotify,
etc.) and contain a device identifier so that events of the
same type coming from different input devices can be
distinguished.

Any kind of input device may be used as an extension input
device. Extension input devices may have 0 or more keys, 0 or
more buttons, and may report 0 or more axes of motion. Motion
may be reported as relative movements from a previous position
or as an absolute position. All valuators reporting motion
information for a given extension input device must report the
same kind of motion information (absolute or relative).

This extension is designed to accommodate new types of input
devices that may be added in the future. The protocol requests
that refer to specific characteristics of input devices
organize that information by input classes. Server implementors
may add new classes of input devices without changing the
protocol requests. Input classes are unique numbers registered
with the X Consortium. Each extension input device may support
multiple input classes.

In XI 1.x, all extension input devices are treated like the
core X keyboard in determining their location and focus. The
server does not track the location of these devices on an
individual basis, and therefore does not echo a cursor to
indicate their current location. Instead, their location is
determined by the location of the core X pointer. Like the core
X keyboard, some may be explicitly focused. If they are not
explicitly focused, their focus is determined by the location
of the core X pointer.

Most input events reported by the server to a client are of
fixed size (32 bytes). In order to represent the change in
state of an input device the extension may need to generate a
sequence of input events. A client side library (such as Xlib)
will typically take these raw input events and format them into
a form more convenient to the client.

1.4 Event Classes
-----------------

In the core protocol a client registers interest in receiving
certain input events directed to a window by modifying that
window's event-mask. Most of the bits in the event mask are
already used to specify interest in core X events. The input
extension specifies a different mechanism by which a client can
express interest in events generated by this extension.

When a client opens a extension input device via the OpenDevice
request, an XDevice structure is returned. Macros are provided
that extract 32-bit numbers called event classes from that
structure, that a client can use to register interest in
extension events via the SelectExtensionEvent request. The
event class combines the desired event type and device id, and
may be thought of as the equivalent of core event masks.

1.5 Input Classes
~~~~~~~~~~~~~~~~~

Some of the input extension requests divide input devices into
classes based on their functionality. This is intended to allow
new classes of input devices to be defined at a later time
without changing the semantics of these requests. The following
input device classes are currently defined:

   KEY
          The device reports key events.

   BUTTON
          The device reports button events.

   VALUATOR
          The device reports valuator data in motion events.

   PROXIMITY
          The device reports proximity events.

   FOCUS
          The device can be focused and reports focus events.

   FEEDBACK
          The device supports feedbacks.

   OTHER
          The ChangeDeviceNotify, DeviceMappingNotify, and
          DeviceStateNotify macros may be invoked passing the
          XDevice structure returned for this device.

Each extension input device may support multiple input classes.
Additional classes may be added in the future. Requests that
support multiple input classes, such as the ListInputDevices
function that lists all available input devices, organize the
data they return by input class. Client programs that use these
requests should not access data unless it matches a class
defined at the time those clients were compiled. In this way,
new classes can be added without forcing existing clients that
use these requests to be recompiled.

2. Requests
-----------

Extension input devices are accessed by client programs through
the use of new protocol requests. This section summarizes the
new requests defined by this extension. The syntax and type
definitions used below follow the notation used for the X11
core protocol.

2.1 Getting the Extension Version
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The GetExtensionVersion request returns version information
about the input extension.

                    GetExtensionVersion
                            name: STRING
                    =>
                            present: BOOL
                            protocol-major-version: CARD16
                            protocol-minor-version: CARD16

The protocol version numbers returned indicate the version of
the input extension supported by the target X server. The
version numbers can be compared to constants defined in the
header file XI.h. Each version is a superset of the previous
versions.

The name must be the name of the Input Extension as defined
in the header file XI.h.

2.2 Listing Available Devices
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

A client that wishes to access a specific device must first
determine whether that device is connected to the X server.
This is done through the ListInputDevices request, which will
return a list of all devices that can be opened by the X
server.

                ListInputDevices
                =>
                input-devices: ListOfDeviceInfo

where

                DEVICEINFO:
                        [type: ATOM
                         id: CARD8
                         num_classes: CARD8
                         use: {IsXKeyboard, IsXPointer, IsXExtensionPointer,
                               IsXExtensionKeyboard, IsExtensionDevice}
                         info: LISTofINPUTINFO
                         name: STRING8]

                INPUTINFO: {KEYINFO, BUTTONINFO, VALUATORINFO}
                KEYINFO:
                        [class: CARD8
                         length: CARD8
                         min-keycode: KEYCODE
                         max-keycode: KEYCODE
                         num-keys: CARD16]
                BUTTONINFO:
                        [class: CARD8
                         length: CARD8
                         num-buttons: CARD16]
                VALUATORINFO:
                        [class: CARD8
                         length: CARD8
                         num_axes: CARD8
                         mode: SETofDEVICEMODE
                         motion_buffer_size: CARD32
                         axes: LISTofAXISINFO]

                AXISINFO:
                        [resolution: CARD32
                         min-val: CARD32
                         max-val: CARD32]
                DEVICEMODE: {Absolute, Relative}

   Errors: None

This request returns a list of all devices that can be opened
by the X server, including the core X keyboard and X pointer.
Some implementations may open all input devices as part of X
initialization, while others may not open an input device until
requested to do so by a client program.

The information returned for each device is as follows:

   type
          The type field is of type Atom and indicates the nature
          of the device. Clients may determine device types by
          invoking the XInternAtom request passing one of the
          names defined in the header file XI.h. The following
          names have been defined to date:

                                      MOUSE
                                      TABLET
                                      KEYBOARD
                                      TOUCHSCREEN
                                      TOUCHPAD
                                      BUTTONBOX
                                      BARCODE
                                      KNOB_BOX
                                      TRACKBALL
                                      QUADRATURE
                                      SPACEBALL
                                      DATAGLOVE
                                      EYETRACKER
                                      CURSORKEYS
                                      FOOTMOUSE
                                      ID_MODULE
                                      ONE_KNOB
                                      NINE_KNOB
                                      JOYSTICK


   id
          The id is a small cardinal value in the range 0-128 that
          uniquely identifies the device. It is assigned to the
          device when it is initialized by the server. Some
          implementations may not open an input device until
          requested by a client program, and may close the device
          when the last client accessing it requests that it be
          closed. If a device is opened by a client program via
          XOpenDevice, then closed via XCloseDevice, then opened
          again, it is not guaranteed to have the same id after
          the second open request.

   num_classes
          The num_classes field is a small cardinal value in the
          range 0-255 that specifies the number of input classes
          supported by the device for which information is
          returned by ListInputDevices. Some input classes, such
          as class Focus and class Proximity do not have any
          information to be returned by ListInputDevices.

   use
          The use field specifies how the device is currently
          being used. If the value is IsXKeyboard, the device is
          currently being used as the X keyboard. If the value is
          IsXPointer, the device is currently being used as the X
          pointer. If the value is IsXExtensionPointer, the device
          is available for use as an extension pointer. If the value
          is IsXExtensionKeyboard, the device is available for use as
          and extension keyboard.
          Older versions of XI report all extension devices as
          IsXExtensionDevice.

   name
          The name field contains a pointer to a null-terminated
          string that corresponds to one of the defined device
          types.

   InputInfo
          InputInfo is one of: KeyInfo, ButtonInfo or
          ValuatorInfo. The first two fields are common to all
          three:

        class
                The class field is a cardinal value in the range
                0-255. It uniquely identifies the class of input
                for which information is returned.

        length
                The length field is a cardinal value in the range
                0-255. It specifies the number of bytes of data
                that are contained in this input class. The length
                includes the class and length fields.

The remaining information returned for input class
KEYCLASS is as follows:

        min_keycode
                min_keycode is of type KEYCODE. It specifies the
                minimum keycode that the device will report. The
                minimum keycode will not be smaller than 8.

        max_keycode
                max_keycode is of type KEYCODE. It specifies the
                maximum keycode that the device will report. The
                maximum keycode will not be larger than 255.

        num_keys
                num_keys is a cardinal value that specifies the
                number of keys that the device has.

The remaining information returned for input class
BUTTONCLASS is as follows:

        num_buttons
                num_buttons is a cardinal value that specifies the
                number of buttons that the device has.

The remaining information returned for input class
VALUATORCLASS is as follows:

        mode
                mode is a constant that has one of the following
                values: Absolute or Relative. Some devices allow
                the mode to be changed dynamically via the
                SetDeviceMode request.

        motion_buffer_size
                motion_buffer_size is a cardinal number that
                specifies the number of elements that can be
                contained in the motion history buffer for the
                device.

        axes
                The axes field contains a pointer to an AXISINFO
                structure.

The information returned for each axis reported by the
device is:

        resolution
                The resolution is a cardinal value in
                counts/meter.

        min_val
                The min_val field is a cardinal value in that
                contains the minimum value the device reports for
                this axis. For devices whose mode is Relative, the
                min_val field will contain 0.

        max_val
                The max_val field is a cardinal value in that
                contains the maximum value the device reports for
                this axis. For devices whose mode is Relative, the
                max_val field will contain 0.

2.3 Enabling Devices
~~~~~~~~~~~~~~~~~~~~

Client programs that wish to access an extension device must
request that the server open that device. This is done via the
OpenDevice request.

                OpenDevice
                        id: CARD8
                =>
                DEVICE:
                        [device_id: XID
                         num_classes: INT32
                         classes: LISTofINPUTCLASSINFO]
                INPUTCLASSINFO:
                         [input_class: CARD8
                         event_type_base: CARD8]

   Errors: Device

This request returns the event classes to be used by the client
to indicate which events the client program wishes to receive.
Each input class may report several event classes. For example,
input class Keys reports DeviceKeyPress and DeviceKeyRelease
event classes. Input classes are unique numbers registered with
the X Consortium. Input class Other exists to report event
classes that are not specific to any one input class, such as
DeviceMappingNotify, ChangeDeviceNotify, and DeviceStateNotify.

The information returned for each device is as follows:

   device_id
          The device_id is a number that uniquely identifies the
          device.

   num_classes
          The num_classes field contains the number of input
          classes supported by this device.

   For each class of input supported by the device, the
   InputClassInfo structure contains the following information:

   input_class
          The input_class is a small cardinal number that
          identifies the class of input.

   event_type_base
          The event_type_base is a small cardinal number that
          specifies the event type of one of the events reported
          by this input class. This information is not directly
          used by client programs. Instead, the Device is used by
          macros that return extension event types and event
          classes. This is described in the section of this
          document entitled "Selecting Extension Device Events".

The information in the InputClassInfo reflects the state of
this device at the time the request was processed.

Before it exits, the client program should explicitly request
that the server close the device. This is done via the
CloseDevice request.

A client may open the same extension device more than once.
Requests after the first successful one return an additional
XDevice structure with the same information as the first, but
otherwise have no effect. A single CloseDevice request will
terminate that client's access to the device.

Closing a device releases any active or passive grabs the
requesting client has established. If the device is frozen only
by an active grab of the requesting client, the queued events
are released when the client terminates.

If a client program terminates without closing a device, the
server will automatically close that device on behalf of the
client. This does not affect any other clients that may be
accessing that device.

                    CloseDevice:
                            device: DEVICE

   Errors: Device

2.4 Changing The Mode Of A Device
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Some devices are capable of reporting either relative or
absolute motion data. To change the mode of a device from
relative to absolute, use the SetDeviceMode request. The valid
values are Absolute or Relative.

This request will fail and return DeviceBusy if another client
already has the device open with a different mode. It will fail
and return AlreadyGrabbed if another client has the device
grabbed. The request will fail with a BadMatch error if the
device has no valuators and reports no axes of motion. The
request will fail with a BadMode error if the requested mode
is not supported by the device.

                    SetDeviceMode
                            device:DEVICE
                            mode: {Absolute, Relative}
                    =>
                            status: {Success, DeviceBusy, AlreadyGrabbed}

   Errors: Device, Match, Mode

2.5 Initializing Valuators on an Input Device
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Some devices that report absolute positional data can be
initialized to a starting value. Devices that are capable of
reporting relative motion or absolute positional data may
require that their valuators be initialized to a starting value
after the mode of the device is changed to Absolute. To
initialize the valuators on such a device, use the
SetDeviceValuators request.

                SetDeviceValuators
                        device: DEVICE
                        first_valuator: CARD8
                        num_valuators: CARD8
                        valuators: LISTOFINT32
                =>
                        status: {Success, AlreadyGrabbed}

   Errors: Length, Device, Match, Value

This request initializes the specified valuators on the
specified extension input device. Valuators are numbered
beginning with zero. Only the valuators in the range specified
by first_valuator and num_valuators are set. If the number of
valuators supported by the device is less than the expression
first_valuator + num_valuators, a Value error will result.

If the request succeeds, Success is returned. If the specified
device is grabbed by some other client, the request will fail
and a status of AlreadyGrabbed will be returned.

2.6 Getting Input Device Controls
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                GetDeviceControl
                        device: DEVICE
                        control: XID
                =>
                controlState: {DeviceState}

where

                DeviceState: DeviceResolutionState

   Errors: Length, Device, Match, Value

This request returns the current state of the specified device
control. The device control must be supported by the target
server and device or an error will result.

If the request is successful, a pointer to a generic
DeviceState structure will be returned. The information
returned varies according to the specified control and is
mapped by a structure appropriate for that control.

GetDeviceControl will fail with a BadValue error if the server
does not support the specified control. It will fail with a
BadMatch error if the device does not support the specified
control.

Supported device controls and the information returned for them
include:

                DEVICE_RESOLUTION:
                    [control: CARD16
                    length: CARD16
                    num_valuators: CARD8
                    resolutions: LISTofCARD32
                    min_resolutions: LISTofCARD32
                    max_resolutions: LISTofCARD32]

This device control returns a list of valuators and the range
of valid resolutions allowed for each. Valuators are numbered
beginning with 0. Resolutions for all valuators on the device
are returned. For each valuator i on the device, resolutions[i]
returns the current setting of the resolution,
min_resolutions[i] returns the minimum valid setting, and
max_resolutions[i] returns the maximum valid setting.

When this control is specified, XGetDeviceControl will fail
with a BadMatch error if the specified device has no valuators.

                ChangeDeviceControl:
                        device: DEVICE
                        XID: controlId
                        control: DeviceControl

where

                DeviceControl: DeviceResolutionControl
                =>
                        status: {Success, DeviceBusy, AlreadyGrabbed}

   Errors: Length, Device, Match, Value

ChangeDeviceControl changes the specified device control
according to the values specified in the DeviceControl
structure. The device control must be supported by the target
server and device or an error will result.

The information passed with this request varies according to
the specified control and is mapped by a structure appropriate
for that control.

ChangeDeviceControl will fail with a BadValue error if the
server does not support the specified control. It will fail
with a BadMatch error if the server supports the specified
control, but the requested device does not. The request will
fail and return a status of DeviceBusy if another client
already has the device open with a device control state that
conflicts with the one specified in the request. It will fail
with a status of AlreadyGrabbed if some other client has
grabbed the specified device. If the request succeeds, Success
is returned. If it fails, the device control is left unchanged.

Supported device controls and the information specified for
them include:

                DEVICE_RESOLUTION:
                        [control: CARD16
                         length: CARD16
                         first_valuator: CARD8
                         num_valuators: CARD8
                         resolutions: LISTofCARD32]

This device control changes the resolution of the specified
valuators on the specified extension input device. Valuators
are numbered beginning with zero. Only the valuators in the
range specified by first_valuator and num_valuators are set. A
value of -1 in the resolutions list indicates that the
resolution for this valuator is not to be changed.
num_valuators specifies the number of valuators in the
resolutions list.

When this control is specified, XChangeDeviceControl will fail
with a BadMatch error if the specified device has no valuators.
If a resolution is specified that is not within the range of
valid values (as returned by XGetDeviceControl) the request
will fail with a BadValue error. If the number of valuators
supported by the device is less than the expression
first_valuator + num_valuators, a BadValue error will result.

If the request fails for any reason, none of the valuator
resolutions will be changed.

ChangeDeviceControl causes the server to send a DevicePresence
event to interested clients.

2.7 Selecting Extension Device Events
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Extension input events are selected using the
SelectExtensionEvent request.

                SelectExtensionEvent
                        interest: LISTofEVENTCLASS
                        window: WINDOW

   Errors: Window, Class, Access

This request specifies to the server the events within the
specified window which are of interest to the client. As with
the core XSelectInput function, multiple clients can select
input on the same window.

XSelectExtensionEvent requires a list of event classes. An
event class is a 32-bit number that combines an event type and
device id, and is used to indicate which event a client wishes
to receive and from which device it wishes to receive it.
Macros are provided to obtain event classes from the data
returned by the XOpenDevice request. The names of these macros
correspond to the desired events, i.e. the DeviceKeyPress is
used to obtain the event class for DeviceKeyPress events. The
syntax of the macro invocation is:

                 DeviceKeyPress (device, event_type, event_class);
                     device: DEVICE
                     event_type: INT
                     event_class: INT

The value returned in event_type is the value that will be
contained in the event type field of the XDeviceKeyPressEvent
when it is received by the client. The value returned in
event_class is the value that should be passed in making an
XSelectExtensionEvent request to receive DeviceKeyPress events.

For DeviceButtonPress events, the client may specify whether or
not an implicit passive grab should be done when the button is
pressed. If the client wants to guarantee that it will receive
a DeviceButtonRelease event for each DeviceButtonPress event it
receives, it should specify the DeviceButtonPressGrab event
class as well as the DeviceButtonPress event class. This
restricts the client in that only one client at a time may
request DeviceButtonPress events from the same device and
window if any client specifies this class.

If any client has specified the DeviceButtonPressGrab class,
any requests by any other client that specify the same device
and window and specify DeviceButtonPress or
DeviceButtonPressGrab will cause an Access error to be
generated.

If only the DeviceButtonPress class is specified, no implicit
passive grab will be done when a button is pressed on the
device. Multiple clients may use this class to specify the same
device and window combination.

A client may also specify the DeviceOwnerGrabButton class. If
it has specified both the DeviceButtonPressGrab and the
DeviceOwnerGrabButton classes, implicit passive grabs will
activate with owner_events set to True. If only the
DeviceButtonPressGrab class is specified, implicit passive
grabs will activate with owner_events set to False.

The client may select DeviceMotion events only when a button is
down. It does this by specifying the event classes
Button1Motion through Button5Motion, or ButtonMotion. An input
device will only support as many button motion classes as it
has buttons.

2.8 Determining Selected Events
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To determine which extension events are currently selected from
a given window, use GetSelectedExtensionEvents.

                GetSelectedExtensionEvents
                        window: WINDOW
                =>
                        this-client: LISTofEVENTCLASS
                        all-clients: LISTofEVENTCLASS

   Errors: Window

This request returns two lists specifying the events selected
on the specified window. One list gives the extension events
selected by this client from the specified window. The other
list gives the extension events selected by all clients from
the specified window. This information is equivalent to that
returned by your-event-mask and all-event-masks in a
GetWindowAttributes request.

2.9 Controlling Event Propagation
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Extension events propagate up the window hierarchy in the same
manner as core events. If a window is not interested in an
extension event, it usually propagates to the closest ancestor
that is interested, unless the dont_propagate list prohibits
it. Grabs of extension devices may alter the set of windows
that receive a particular extension event.

Client programs may control extension event propagation through
the use of the following two requests.

XChangeDeviceDontPropagateList adds an event to or deletes an
event from the do_not_propagate list of extension events for
the specified window. This list is maintained for the life of
the window, and is not altered if the client terminates.

                ChangeDeviceDontPropagateList
                        window: WINDOW
                        eventclass: LISTofEVENTCLASS
                        mode: {AddToList, DeleteFromList}

   Errors: Window, Class, Mode

This function modifies the list specifying the events that are
not propagated to the ancestors of the specified window. You
may use the modes AddToList or DeleteFromList.

                GetDeviceDontPropagateList
                        window: WINDOW
                =>
                        dont-propagate-list: LISTofEVENTCLASS

   Errors: Window

This function returns a list specifying the events that are not
propagated to the ancestors of the specified window.

2.10 Sending Extension Events
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

One client program may send an event to another via the
XSendExtensionEvent function.

The event in the XEvent structure must be one of the events
defined by the input extension, so that the X server can
correctly byte swap the contents as necessary. The contents of
the event are otherwise unaltered and unchecked by the X server
except to force send_event to True in the forwarded event and
to set the sequence number in the event correctly.

XSendExtensionEvent returns zero if the conversion-to-wire
protocol failed, otherwise it returns nonzero.

                SendExtensionEvent
                        device: DEVICE
                        destination: WINDOW
                        propagate: BOOL
                        eventclass: LISTofEVENTCLASS
                        event: XEVENT

   Errors: Device, Value, Class, Window

2.11 Getting Motion History
~~~~~~~~~~~~~~~~~~~~~~~~~~~

                GetDeviceMotionEvents
                        device: DEVICE
                        start, stop: TIMESTAMP or CurrentTime
                =>
                        nevents_return: CARD32
                        mode_return: {Absolute, Relative}
                        axis_count_return: CARD8
                        events: LISTofDEVICETIMECOORD

where

                DEVICETIMECOORD:
                        [data: LISTofINT32
                         time: TIMESTAMP]

   Errors: Device, Match

This request returns all positions in the device's motion
history buffer that fall between the specified start and stop
times inclusive. If the start time is in the future, or is
later than the stop time, no positions are returned.

The data field of the DEVICETIMECOORD structure is a sequence
of data items. Each item is of type INT32, and there is one
data item per axis of motion reported by the device. The number
of axes reported by the device is returned in the axis_count
variable.

The value of the data items depends on the mode of the device,
which is returned in the mode variable. If the mode is
Absolute, the data items are the raw values generated by the
device. These may be scaled by the client program using the
maximum values that the device can generate for each axis of
motion that it reports. The maximum and minimum values for each
axis are reported by the ListInputDevices request.

If the mode is Relative, the data items are the relative values
generated by the device. The client program must choose an
initial position for the device and maintain a current position
by accumulating these relative values.

2.12 Changing The Core Devices
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

These requests are provided to change which physical device is
used as the X pointer or X keyboard. These requests are
deprecated in servers supporting XI 1.4 and above, and will
always return a a BadDevice error.

Using these requests may change the characteristics of the core
devices. The new pointer device may have a different number of
buttons than the old one did, or the new keyboard device may
have a different number of keys or report a different range of
keycodes. Client programs may be running that depend on those
characteristics. For example, a client program could allocate
an array based on the number of buttons on the pointer device,
and then use the button numbers received in button events as
indices into that array. Changing the core devices could cause
such client programs to behave improperly or abnormally
terminate.

These requests change the X keyboard or X pointer device and
generate an ChangeDeviceNotify event and a MappingNotify event.
The ChangeDeviceNotify event is sent only to those clients that
have expressed an interest in receiving that event via the
XSelectExtensionEvent request. The specified device becomes the
new X keyboard or X pointer device. The location of the core
device does not change as a result of this request.

These requests fail and return AlreadyGrabbed if either the
specified device or the core device it would replace are
grabbed by some other client. They fail and return GrabFrozen
if either device is frozen by the active grab of another
client.

These requests fail with a BadDevice error if the specified
device is invalid, or has not previously been opened via
OpenDevice. To change the X keyboard device, use the
ChangeKeyboardDevice request. The specified device must support
input class Keys (as reported in the ListInputDevices request)
or the request will fail with a BadMatch error. Once the device
has successfully replaced one of the core devices, it is
treated as a core device until it is in turn replaced by
another ChangeDevice request, or until the server terminates.
The termination of the client that changed the device will not
cause it to change back. Attempts to use the CloseDevice
request to close the new core device will fail with a BadDevice
error.

The focus state of the new keyboard is the same as the focus
state of the old X keyboard. If the new keyboard was not
initialized with a FocusRec, one is added by the
ChangeKeyboardDevice request. The X keyboard is assumed to have
a KbdFeedbackClassRec. If the device was initialized without a
KbdFeedbackClassRec, one will be added by this request. The
KbdFeedbackClassRec will specify a null routine as the control
procedure and the bell procedure.

                ChangeKeyboardDevice
                        device: DEVICE
                =>
                        status: Success, AlreadyGrabbed, Frozen

   Errors: Device, Match

To change the X pointer device, use the ChangePointerDevice
request. The specified device must support input class
Valuators (as reported in the ListInputDevices request) or the
request will fail with a BadMatch error. The valuators to be
used as the x- and y-axes of the pointer device must be
specified. Data from other valuators on the device will be
ignored.

The X pointer device does not contain a FocusRec. If the new
pointer was initialized with a FocusRec, it is freed by the
ChangePointerDevice request. The X pointer is assumed to have a
ButtonClassRec and a PtrFeedbackClassRec. If the device was
initialized without a ButtonClassRec or a PtrFeedbackClassRec,
one will be added by this request. The ButtonClassRec added
will have no buttons, and the PtrFeedbackClassRec will specify
a null routine as the control procedure.

If the specified device reports absolute positional
information, and the server implementation does not allow such
a device to be used as the X pointer, the request will fail
with a BadDevice error.

Once the device has successfully replaced one of the core
devices, it is treated as a core device until it is in turn
replaced by another ChangeDevice request, or until the server
terminates. The termination of the client that changed the
device will not cause it to change back. Attempts to use the
CloseDevice request to close the new core device will fail with
a BadDevice error.

                ChangePointerDevice
                        device: DEVICE
                        xaxis: CARD8
                        yaxis: CARD8
                =>
                     status: Success, AlreadyGrabbed, Frozen

   Errors: Device, Match

2.12 Event Synchronization And Core Grabs
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Implementation of the input extension requires an extension of
the meaning of event synchronization for the core grab
requests. This is necessary in order to allow window managers
to freeze all input devices with a single request.

The core grab requests require a pointer_mode and keyboard_mode
argument. The meaning of these modes is changed by the input
extension. For the XGrabPointer and XGrabButton requests,
pointer_mode controls synchronization of the pointer device,
and keyboard_mode controls the synchronization of all other
input devices. For the XGrabKeyboard and XGrabKey requests,
pointer_mode controls the synchronization of all input devices
except the X keyboard, while keyboard_mode controls the
synchronization of the keyboard. When using one of the core
grab requests, the synchronization of extension devices is
controlled by the mode specified for the device not being
grabbed.

2.13 Extension Active Grabs
~~~~~~~~~~~~~~~~~~~~~~~~~~~

Active grabs of extension devices are supported via the
GrabDevice request in the same way that core devices are
grabbed using the core GrabKeyboard request, except that a
Device is passed as a function parameter. A list of events that
the client wishes to receive is also passed. The UngrabDevice
request allows a previous active grab for an extension device
to be released.

To grab an extension device, use the GrabDevice request. The
device must have previously been opened using the OpenDevice
request.

                GrabDevice
                        device: DEVICE
                        grab-window: WINDOW
                        owner-events: BOOL
                        event-list: LISTofEVENTCLASS
                        this-device-mode: {Synchronous, Asynchronous}
                        other-device-mode: {Synchronous, Asynchronous}
                        time:TIMESTAMP or CurrentTime
                =>
                        status: Success, AlreadyGrabbed, Frozen,
                                InvalidTime, NotViewable

   Errors: Device, Window, Value

This request actively grabs control of the specified input
device. Further input events from this device are reported only
to the grabbing client. This request overrides any previous
active grab by this client for this device.

The event-list parameter is a pointer to a list of event
classes. These are used to indicate which events the client
wishes to receive while the device is grabbed. Only event
classes obtained from the grabbed device are valid.

If owner-events is False, input events generated from this
device are reported with respect to grab-window, and are only
reported if selected by being included in the event-list. If
owner-events is True, then if a generated event would normally
be reported to this client, it is reported normally, otherwise
the event is reported with respect to the grab-window, and is
only reported if selected by being included in the event-list.
For either value of owner-events, unreported events are
discarded.

If this-device-mode is Asynchronous, device event processing
continues normally. If the device is currently frozen by this
client, then processing of device events is resumed. If
this-device-mode is Synchronous, the state of the grabbed
device (as seen by means of the protocol) appears to freeze,
and no further device events are generated by the server until
the grabbing client issues a releasing AllowDeviceEvents
request or until the device grab is released. Actual device
input events are not lost while the device is frozen; they are
simply queued for later processing.

If other-device-mode is Asynchronous, event processing is
unaffected by activation of the grab. If other-device-mode is
Synchronous, the state of all input devices except the grabbed
one (as seen by means of the protocol) appears to freeze, and
no further events are generated by the server until the
grabbing client issues a releasing AllowDeviceEvents request or
until the device grab is released. Actual events are not lost
while the devices are frozen; they are simply queued for later
processing.

This request generates DeviceFocusIn and DeviceFocusOut events.

This request fails and returns:

   AlreadyGrabbed
          If the device is actively grabbed by some other client.

   NotViewable
          If grab-window is not viewable.

   InvalidTime
          If the specified time is earlier than the last-grab-time
          for the specified device or later than the current X
          server time. Otherwise, the last-grab-time for the
          specified device is set to the specified time and
          CurrentTime is replaced by the current X server time.

   Frozen
          If the device is frozen by an active grab of another
          client.

If a grabbed device is closed by a client while an active grab
by that client is in effect, that active grab will be released.
Any passive grabs established by that client will be released.
If the device is frozen only by an active grab of the
requesting client, it is thawed.

To release a grab of an extension device, use UngrabDevice.

               UngrabDevice
                       device: DEVICE
                       time: TIMESTAMP or CurrentTime

   Errors: Device

This request releases the device if this client has it actively
grabbed (from either GrabDevice or GrabDeviceKey) and releases
any queued events. If any devices were frozen by the grab,
UngrabDevice thaws them. The request has no effect if the
specified time is earlier than the last-device-grab time or is
later than the current server time.

This request generates DeviceFocusIn and DeviceFocusOut events.

An UngrabDevice is performed automatically if the event window
for an active device grab becomes not viewable.

2.14 Passively Grabbing A Key
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Passive grabs of buttons and keys on extension devices are
supported via the GrabDeviceButton and GrabDeviceKey requests.
These passive grabs are released via the UngrabDeviceKey and
UngrabDeviceButton requests.

To passively grab a single key on an extension device, use
GrabDeviceKey. That device must have previously been opened
using the OpenDevice request.

            GrabDeviceKey
                    device: DEVICE
                    keycode: KEYCODE or AnyKey
                    modifiers: SETofKEYMASK or AnyModifier
                    modifier-device: DEVICE or NULL
                    grab-window: WINDOW
                    owner-events: BOOL
                    event-list: LISTofEVENTCLASS
                    this-device-mode: {Synchronous, Asynchronous}
                    other-device-mode: {Synchronous, Asynchronous}

   Errors: Device, Match, Access, Window, Value

This request is analogous to the core GrabKey request. It
establishes a passive grab on a device. Consequently, in the
future:

     * IF the device is not grabbed and the specified key, which
       itself can be a modifier key, is logically pressed when the
       specified modifier keys logically are down on the specified
       modifier device (and no other keys are down),
     * AND no other modifier keys logically are down,
     * AND EITHER the grab window is an ancestor of (or is) the
       focus window OR the grab window is a descendent of the
       focus window and contains the pointer,
     * AND a passive grab on the same device and key combination
       does not exist on any ancestor of the grab window,
     * THEN the device is actively grabbed, as for GrabDevice, the
       last-device-grab time is set to the time at which the key
       was pressed (as transmitted in the DeviceKeyPress event),
       and the DeviceKeyPress event is reported.

The interpretation of the remaining arguments is as for
GrabDevice. The active grab is terminated automatically when
logical state of the device has the specified key released
(independent of the logical state of the modifier keys).

Note that the logical state of a device (as seen by means of
the X protocol) may lag the physical state if device event
processing is frozen.

A modifier of AnyModifier is equivalent to issuing the request
for all possible modifier combinations (including the
combination of no modifiers). It is not required that all
modifiers specified have currently assigned keycodes. A key of
AnyKey is equivalent to issuing the request for all possible
keycodes. Otherwise, the key must be in the range specified by
min-keycode and max-keycode in the ListInputDevices request. If
it is not within that range, GrabDeviceKey generates a Value
error.

NULL may be passed for the modifier_device. If the
modifier_device is NULL, the core X keyboard is used as the
modifier_device.

An Access error is generated if some other client has issued a
GrabDeviceKey with the same device and key combination on the
same window. When using AnyModifier or AnyKey, the request
fails completely and the X server generates a Access error and
no grabs are established if there is a conflicting grab for any
combination.

This request cannot be used to grab a key on the X keyboard
device. The core GrabKey request should be used for that
purpose.

To release a passive grab of a single key on an extension
device, use UngrabDeviceKey.

           UngrabDeviceKey
                   device: DEVICE
                   keycode: KEYCODE or AnyKey
                   modifiers: SETofKEYMASK or AnyModifier
                   modifier-device: DEVICE or NULL
                   grab-window: WINDOW

   Errors: Device, Match, Window, Value, Alloc

This request is analogous to the core UngrabKey request. It
releases the key combination on the specified window if it was
grabbed by this client. A modifier of AnyModifier is equivalent
to issuing the request for all possible modifier combinations
(including the combination of no modifiers). A key of AnyKey is
equivalent to issuing the request for all possible keycodes.
This request has no effect on an active grab.

NULL may be passed for the modifier_device. If the
modifier_device is NULL, the core X keyboard is used as the
modifier_device.

2.15 Passively Grabbing A Button
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To establish a passive grab for a single button on an extension
device, use GrabDeviceButton.

                GrabDeviceButton
                        device: DEVICE
                        button: BUTTON or AnyButton
                        modifiers: SETofKEYMASK or AnyModifier
                        modifier-device: DEVICE or NULL
                        grab-window: WINDOW
                        owner-events: BOOL
                        event-list: LISTofEVENTCLASS
                        this-device-mode: {Synchronous, Asynchronous}
                        other-device-mode: {Synchronous, Asynchronous}

   Errors: Device, Match, Window, Access, Value

This request is analogous to the core GrabButton request. It
establishes an explicit passive grab for a button on an
extension input device. Since the server does not track
extension devices, no cursor is specified with this request.
For the same reason, there is no confine-to parameter. The
device must have previously been opened using the OpenDevice
request.

The GrabDeviceButton request establishes a passive grab on a
device. Consequently, in the future,

   * IF the device is not grabbed and the specified button is
     logically pressed when the specified modifier keys
     logically are down (and no other buttons or modifier
     keys are down),

   * AND the grab window contains the device,

   * AND a passive grab on the same device and button/ key
     combination does not exist on any ancestor of the grab
     window,

   * THEN the device is actively grabbed, as for GrabDevice,
     the last-grab time is set to the time at which the
     button was pressed (as transmitted in the
     DeviceButtonPress event), and the DeviceButtonPress
     event is reported.

The interpretation of the remaining arguments is as for
GrabDevice. The active grab is terminated automatically when
logical state of the device has all buttons released
(independent of the logical state of the modifier keys).

Note that the logical state of a device (as seen by means of
the X protocol) may lag the physical state if device event
processing is frozen.

A modifier of AnyModifier is equivalent to issuing the request
for all possible modifier combinations (including the
combination of no modifiers). It is not required that all
modifiers specified have currently assigned keycodes. A button
of AnyButton is equivalent to issuing the request for all
possible buttons. It is not required that the specified button
be assigned to a physical button.

NULL may be passed for the modifier_device. If the
modifier_device is NULL, the core X keyboard is used as the
modifier_device.

An Access error is generated if some other client has issued a
GrabDeviceButton with the same device and button combination on
the same window. When using AnyModifier or AnyButton, the
request fails completely and the X server generates a Access
error and no grabs are established if there is a conflicting
grab for any combination. The request has no effect on an
active grab.

This request cannot be used to grab a button on the X pointer
device. The core GrabButton request should be used for that
purpose.

To release a passive grab of a button on an extension device,
use UngrabDeviceButton.

                UngrabDeviceButton
                        device: DEVICE
                        button: BUTTON or AnyButton
                        modifiers: SETofKEYMASK or AnyModifier
                        modifier-device: DEVICE or NULL
                        grab-window: WINDOW

   Errors: Device, Match, Window, Value, Alloc

This request is analogous to the core UngrabButton request. It
releases the passive button/key combination on the specified
window if it was grabbed by the client. A modifiers of
AnyModifier is equivalent to issuing the request for all
possible modifier combinations (including the combination of no
modifiers). A button of AnyButton is equivalent to issuing the
request for all possible buttons. This request has no effect on
an active grab. The device must have previously been opened
using the OpenDevice request otherwise a Device error will be
generated.

NULL may be passed for the modifier_device. If the
modifier_device is NULL, the core X keyboard is used as the
modifier_device.

This request cannot be used to ungrab a button on the X pointer
device. The core UngrabButton request should be used for that
purpose.

2.16 Thawing A Device
~~~~~~~~~~~~~~~~~~~~~

To allow further events to be processed when a device has been
frozen, use AllowDeviceEvents.

                AllowDeviceEvents
                        device: DEVICE
                        event-mode: {AsyncThisDevice, SyncThisDevice, AsyncOtherDevices,
                        ReplayThisdevice, AsyncAll, or SyncAll}
                        time:TIMESTAMP or CurrentTime

   Errors: Device, Value

The AllowDeviceEvents request releases some queued events if
the client has caused a device to freeze. The request has no
effect if the specified time is earlier than the last-grab time
of the most recent active grab for the client, or if the
specified time is later than the current X server time.

The following describes the processing that occurs depending on
what constant you pass to the event-mode argument:

   * If the specified device is frozen by the client, event
     processing for that device continues as usual. If the
     device is frozen multiple times by the client on behalf
     of multiple separate grabs, AsyncThisDevice thaws for
     all. AsyncThisDevice has no effect if the specified
     device is not frozen by the client, but the device need
     not be grabbed by the client.

   * If the specified device is frozen and actively grabbed
     by the client, event processing for that device
     continues normally until the next button or key event is
     reported to the client. At this time, the specified
     device again appears to freeze. However, if the reported
     event causes the grab to be released, the specified
     device does not freeze. SyncThisDevice has no effect if
     the specified device is not frozen by the client or is
     not grabbed by the client.

   * If the specified device is actively grabbed by the
     client and is frozen as the result of an event having
     been sent to the client (either from the activation of a
     GrabDeviceButton or from a previous AllowDeviceEvents
     with mode SyncThisDevice, but not from a Grab), the grab
     is released and that event is completely reprocessed.
     This time, however, the request ignores any passive
     grabs at or above (towards the root) the grab-window of
     the grab just released. The request has no effect if the
     specified device is not grabbed by the client or if it
     is not frozen as the result of an event.

   * If the remaining devices are frozen by the client, event
     processing for them continues as usual. If the other
     devices are frozen multiple times by the client on
     behalf of multiple separate grabs, AsyncOtherDevices
     “thaws” for all. AsyncOtherDevices has no effect if the
     devices are not frozen by the client, but those devices
     need not be grabbed by the client.

   * If all devices are frozen by the client, event
     processing (for all devices) continues normally until
     the next button or key event is reported to the client
     for a grabbed device (button event for the grabbed
     device, key or motion event for the device), at which
     time the devices again appear to freeze. However, if the
     reported event causes the grab to be released, then the
     devices do not freeze (but if any device is still
     grabbed, then a subsequent event for it will still cause
     all devices to freeze). SyncAll has no effect unless all
     devices are frozen by the client. If any device is
     frozen twice by the client on behalf of two separate
     grabs, SyncAll "thaws" for both (but a subsequent freeze
     for SyncAll will only freeze each device once).

   * If all devices are frozen by the client, event
     processing (for all devices) continues normally. If any
     device is frozen multiple times by the client on behalf
     of multiple separate grabs, AsyncAll "thaws" for all.
     AsyncAll has no effect unless all devices are frozen by
     the client.

AsyncThisDevice, SyncThisDevice, and ReplayThisDevice
have no effect on the processing of events from the
remaining devices. AsyncOtherDevices has no effect on
the processing of events from the specified device. When
the event_mode is SyncAll or AsyncAll, the device
parameter is ignored.

It is possible for several grabs of different devices
(by the same or different clients) to be active
simultaneously. If a device is frozen on behalf of any
grab, no event processing is performed for the device.
It is possible for a single device to be frozen because
of several grabs. In this case, the freeze must be
released on behalf of each grab before events can again
be processed.

2.17 Controlling Device Focus
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The current focus window for an extension input device can be
determined using the GetDeviceFocus request. Extension devices
are focused using the SetDeviceFocus request in the same way
that the keyboard is focused using the SetInputFocus request,
except that a device is specified as part of the request. One
additional focus state, FollowKeyboard, is provided for
extension devices.

To get the current focus state, revert state, and focus time of
an extension device, use GetDeviceFocus.

                GetDeviceFocus
                        device: DEVICE
                =>
                        focus: WINDOW, PointerRoot, FollowKeyboard, or None
                        revert-to: Parent, PointerRoot, FollowKeyboard, or None
                        focus-time: TIMESTAMP

   Errors: Device, Match

This request returns the current focus state, revert-to state,
and last-focus-time of an extension device.

To set the focus of an extension device, use SetDeviceFocus.

                SetDeviceFocus
                        device: DEVICE
                        focus: WINDOW, PointerRoot, FollowKeyboard, or None
                        revert-to: Parent, PointerRoot, FollowKeyboard, or None
                        focus-time: TIMESTAMP

   Errors: Device, Window, Value, Match

This request changes the focus for an extension input device
and the last-focus-change-time. The request has no effect if
the specified time is earlier than the last-focus-change-time
or is later than the current X server time. Otherwise, the
last-focus-change-time is set to the specified time, with
CurrentTime replaced by the current server time.

The action taken by the server when this request is requested
depends on the value of the focus argument:

   * If the focus argument is None, all input events from
     this device will be discarded until a new focus window
     is set. In this case, the revert-to argument is ignored.

   * If a window ID is assigned to the focus argument, it
     becomes the focus window of the device. If an input
     event from the device would normally be reported to this
     window or to one of its inferiors, the event is reported
     normally. Otherwise, the event is reported relative to
     the focus window.

   * If you assign PointerRoot to the focus argument, the
     focus window is dynamically taken to be the root window
     of whatever screen the pointer is on at each input
     event. In this case, the revert-to argument is ignored.

   * If you assign FollowKeyboard to the focus argument, the
     focus window is dynamically taken to be the same as the
     focus of the X keyboard at each input event.
     The specified focus window must be viewable at the time
     of the request (else a Match error). If the focus window
     later becomes not viewable, the X server evaluates the
     revert-to argument to determine the new focus window.

   * If you assign RevertToParent to the revert-to argument,
     the focus reverts to the parent (or the closest viewable
     ancestor), and the new revert-to value is taken to be
     RevertToNone.

   * If you assign RevertToPointerRoot,
     RevertToFollowKeyboard, or RevertToNone to the revert-to
     argument, the focus reverts to that value.

When the focus reverts, the X server generates DeviceFocusIn
and DeviceFocusOut events, but the last-focus-change time is
not affected.

This request causes the X server to generate DeviceFocusIn and
DeviceFocusOut events.

2.18 Controlling Device Feedback
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To get the settings of feedbacks on an extension device, use
GetFeedbackControl. This request provides functionality
equivalent to the core GetKeyboardControl and GetPointerControl
functions. It also provides a way to control displays
associated with an input device that are capable of displaying
an integer or string.

                GetFeedbackControl
                        device: DEVICE
                =>
                        num_feedbacks_return: CARD16
                        return_value: LISTofFEEDBACKSTATE

where

                    FEEDBACKSTATE: {KbdFeedbackState, PtrFeedbackState,
                                    IntegerFeedbackState, StringFeedbackState,
                                    BellFeedbackState, LedFeedbackState}

Feedbacks are reported by class. Those feedbacks that are
reported for the core keyboard device are in class KbdFeedback,
and are returned in the KbdFeedbackState structure. The members
of that structure are as follows:

                CLASS Kbd:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         key_click_percent: CARD8
                         bell_percent: CARD8
                         bell_pitch: CARD16
                         bell_duration: CARD16
                         led_value: BITMASK
                         global_auto_repeat: {AutoRepeatModeOn, AutoRepeatModeOff}
                         auto_repeats: LISTofCARD8]

Those feedbacks that are equivalent to those reported for the
core pointer are in feedback class PtrFeedback and are reported
in the PtrFeedbackState structure. The members of that
structure are:

                CLASS Ptr:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         accelNumerator: CARD16
                         accelDenominator: CARD16
                         threshold: CARD16]

Some input devices provide a means of displaying an integer.
Those devices will support feedback class IntegerFeedback,
which is reported in the IntegerFeedbackState structure. The
members of that structure are:

                  CLASS Integer:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         resolution: CARD32
                         min-val: INT32
                         max-val: INT32]

Some input devices provide a means of displaying a string.
Those devices will support feedback class StringFeedback, which
is reported in the StringFeedbackState structure. The members
of that structure are:

                  CLASS String:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         max_symbols: CARD16
                         num_keysyms_supported: CARD16
                         keysyms_supported: LISTofKEYSYM]

Some input devices contain a bell. Those devices will support
feedback class BellFeedback, which is reported in the
BellFeedbackState structure. The members of that structure are:

                  CLASS Bell:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         percent: CARD8
                         pitch: CARD16
                         duration: CARD16]

The percent sets the base volume for the bell between 0 (off)
and 100 (loud) inclusive, if possible. Setting to -1 restores
the default. Other negative values generate a Value error.

The pitch sets the pitch (specified in Hz) of the bell, if
possible. Setting to -1 restores the default. Other negative
values generate a Value error.

The duration sets the duration (specified in milliseconds) of
the bell, if possible. Setting to -1 restores the default.
Other negative values generate a Value error.

A bell generator connected with the console but not directly on
the device is treated as if it were part of the device. Some
input devices contain LEDs. Those devices will support feedback
class Led, which is reported in the LedFeedbackState structure.
The members of that structure are:

                  CLASS Led:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         led_mask: BITMASK
                         led_value: BITMASK]

Each bit in led_mask indicates that the corresponding led is
supported by the feedback. At most 32 LEDs per feedback are
supported. No standard interpretation of LEDs is defined.

This function will fail with a BadMatch error if the device
specified in the request does not support feedbacks.

   Errors: Device, Match

To change the settings of a feedback on an extension device,
use ChangeFeedbackControl.

                ChangeFeedbackControl
                        device: DEVICE
                        feedbackid: CARD8
                        value-mask: BITMASK
                        value: FEEDBACKCONTROL
                        FEEDBACKCONTROL: {KBDFEEDBACKCONTROL,
                                          PTRFEEDBACKCONTROL,
                                          INTEGERFEEDBACKCONTROL,
                                          STRINGFEEDBACKCONTROL,
                                          BELLFEEDBACKCONTROL,
                                          LEDFEEDBACKCONTROL}

   Errors: Device, Match, Value

Feedback controls are grouped by class. Those feedbacks that
are equivalent to those supported by the core keyboard are
controlled by feedback class KbdFeedbackClass using the
KbdFeedbackControl structure. The members of that structure
are:

                KBDFEEDBACKCTL
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         key_click_percent: INT8
                         bell_percent: INT8
                         bell_pitch: INT16
                         bell_duration: INT16
                         led_mask: INT32
                         led_value: INT32
                         key: KEYCODE
                         auto_repeat_mode: {AutoRepeatModeOn, AutoRepeatModeOff,
                                            AutoRepeatModeDefault}]

The key_click_percent sets the volume for key clicks between 0
(off) and 100 (loud) inclusive, if possible. Setting to -1
restores the default. Other negative values generate a Value
error.

If both auto_repeat_mode and key are specified, then the
auto_repeat_mode of that key is changed, if possible. If only
auto_repeat_mode is specified, then the global auto-repeat mode
for the entire keyboard is changed, if possible, without
affecting the per-key settings. It is a Match error if a key is
specified without an auto_repeat_mode.

The order in which controls are verified and altered is
server-dependent. If an error is generated, a subset of the
controls may have been altered.

Those feedback controls equivalent to those of the core pointer
are controlled by feedback class PtrFeedbackClass using the
PtrFeedbackControl structure. The members of that structure are
as follows:

                PTRFEEDBACKCTL:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         accelNumerator: INT16
                         accelDenominator: INT16
                         threshold: INT16]

The acceleration, expressed as a fraction, is a multiplier for
movement. For example, specifying 3/1 means the device moves
three times as fast as normal. The fraction may be rounded
arbitrarily by the X server. Acceleration only takes effect if
the device moves more than threshold pixels at once and only
applies to the amount beyond the value in the threshold
argument. Setting a value to -1 restores the default. The
values of the do-accel and do-threshold arguments must be
nonzero for the device values to be set. Otherwise, the
parameters will be unchanged. Negative values generate a Value
error, as does a zero value for the accel-denominator argument.

Some devices are capable of displaying an integer. This is done
using feedback class IntegerFeedbackClass using the
IntegerFeedbackControl structure. The members of that structure
are as follows:

                INTEGERCTL:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         int_to_display: INT32]

Some devices are capable of displaying a string. This is done
using feedback class StringFeedbackClass using the
StringFeedbackCtl structure. The members of that structure are
as follows:

                STRINGCTL:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         syms_to_display: LISTofKEYSYMS]

Some devices contain a bell. This is done using feedback class
BellFeedbackClass using the BellFeedbackControl structure. The
members of that structure are as follows:

                BELLCTL:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         percent: INT8
                         pitch: INT16
                         duration: INT16]

Some devices contain leds. These can be turned on and off using
the LedFeedbackControl structure. The members of that structure
are as follows:

                LEDCTL:
                        [class: CARD8
                         length: CARD16
                         feedback id: CARD8
                         led_mask: BITMASK
                         led_value: BITMASK]

   Errors: Device, Match, Value

2.20 Ringing a Bell on an Input Device
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To ring a bell on an extension input device, use DeviceBell.

                DeviceBell:
                        device: DEVICE
                        feedbackclass: CARD8
                        feedbackid: CARD8
                        percent: INT8

   Errors: Device, Value

This request is analogous to the core Bell request. It rings
the specified bell on the specified input device feedback,
using the specified volume. The specified volume is relative to
the base volume for the feedback. If the value for the percent
argument is not in the range -100 to 100 inclusive, a Value
error results. The volume at which the bell rings when the
percent argument is nonnegative is:

                base - [(base * percent) / 100] + percent

The volume at which the bell rings when the percent argument is
negative is:

                base + [(base * percent) / 100]

To change the base volume of the bell, use
ChangeFeedbackControl request.

Controlling Device Encoding

To get the keyboard mapping of an extension device that has
keys, use GetDeviceKeyMapping.

                GetDeviceKeyMapping
                        device: DEVICE
                        first-keycode: KEYCODE
                        count: CARD8
                =>
                        keysyms-per-keycode: CARD8
                        keysyms: LISTofKEYSYM

   Errors: Device, Match, Value

This request returns the symbols for the specified number of
keycodes for the specified extension device, starting with the
specified keycode. The first-keycode must be greater than or
equal to min-keycode as returned in the connection setup (else
a Value error), and

                first-keycode + count - 1

must be less than or equal to max-keycode as returned in the
connection setup (else a Value error). The number of elements
in the keysyms list is

                count * keysyms-per-keycode

and KEYSYM number N (counting from zero) for keycode K has an
index (counting from zero) of

                (K - first-keycode) * keysyms-per-keycode + N

in keysyms. The keysyms-per-keycode value is chosen arbitrarily
by the server to be large enough to report all requested
symbols. A special KEYSYM value of NoSymbol is used to fill in
unused elements for individual keycodes.

If the specified device has not first been opened by this
client via OpenDevice, or if that device does not support input
class Keys, this request will fail with a Device error.

To change the keyboard mapping of an extension device that has
keys, use ChangeDeviceKeyMapping.

                ChangeDeviceKeyMapping
                        device: DEVICE
                        first-keycode: KEYCODE
                        keysyms-per-keycode: CARD8
                        keysyms: LISTofKEYSYM
                        num_codes: CARD8

   Errors: Device, Match, Value, Alloc

This request is analogous to the core ChangeKeyMapping request.
It defines the symbols for the specified number of keycodes for
the specified extension device. If the specified device has not
first been opened by this client via OpenDevice, or if that
device does not support input class Keys, this request will
fail with a Device error.

The number of elements in the keysyms list must be a multiple
of keysyms_per_keycode. Otherwise, ChangeDeviceKeyMapping
generates a Length error. The specified first_keycode must be
greater than or equal to the min_keycode value returned by the
ListInputDevices request, or this request will fail with a
Value error. In addition, if the following expression is not
less than the max_keycode value returned by the
ListInputDevices request, the request will fail with a Value
error:

                first_keycode + (num_codes / keysyms_per_keycode) - 1

To obtain the keycodes that are used as modifiers on an
extension device that has keys, use GetDeviceModifierMapping.

                GetDeviceModifierMapping
                        device: DEVICE
                =>
                        keycodes-per-modifier: CARD8
                        keycodes: LISTofKEYCODE

   Errors: Device, Match

This request is analogous to the core GetModifierMapping
request. This request returns the keycodes of the keys being
used as modifiers. The number of keycodes in the list is
8*keycodes-per-modifier. The keycodes are divided into eight
sets, with each set containing keycodes-per-modifier elements.
The sets are assigned in order to the modifiers Shift, Lock,
Control, Mod1, Mod2, Mod3, Mod4, and Mod5. The
keycodes-per-modifier value is chosen arbitrarily by the
server; zeroes are used to fill in unused elements within each
set. If only zero values are given in a set, the use of the
corresponding modifier has been disabled. The order of keycodes
within each set is chosen arbitrarily by the server.

To set which keycodes that are to be used as modifiers for an
extension device, use SetDeviceModifierMapping.

                SetDeviceModifierMapping
                        device: DEVICE
                        keycodes-per-modifier: CARD8
                        keycodes: LISTofKEYCODE
                =>
                        status: {Success, Busy, Failed}

   Errors: Device, Match, Value, Alloc

This request is analogous to the core SetModifierMapping
request. This request specifies the keycodes (if any) of the
keys to be used as modifiers. The number of keycodes in the
list must be 8*keycodes-per-modifier (else a Length error). The
keycodes are divided into eight sets, with the sets, with each
set containing keycodes-per-modifier elements. The sets are
assigned in order to the modifiers Shift, Lock, Control, Mod1,
Mod2, Mod3, Mod4, and Mod5. Only non-zero keycode values are
used within each set; zero values are ignored. All of the
non-zero keycodes must be in the range specified by min-keycode
and max-keycode in the ListInputDevices request (else a Value
error). The order of keycodes within a set does not matter. If
no non-zero values are specified in a set, the use of the
corresponding modifier is disabled, and the modifier bit will
always be zero. Otherwise, the modifier bit will be one
whenever at least one of the keys in the corresponding set is
in the down position.

A server can impose restrictions on how modifiers can be
changed (for example, if certain keys do not generate up
transitions in hardware or if multiple keys per modifier are
not supported). If some such restriction is violated, the status
reply is MappingFailed, and none of the modifiers are changed.

If the new keycodes specified for a modifier differ from those
currently defined and any (current or new) keys for that
modifier are in the logically down state, the status reply is
MappingBusy, and none of the modifiers are changed.

This request generates a DeviceMappingNotify event on a Success
status. The DeviceMappingNotify event will be sent only to
those clients that have expressed an interest in receiving that
event via the XSelectExtensionEvent request.

2.20 Controlling Button Mapping
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

These requests are analogous to the core GetPointerMapping and
ChangePointerMapping requests. They allow a client to determine
the current mapping of buttons on an extension device, and to
change that mapping.

To get the current button mapping for an extension device, use
GetDeviceButtonMapping.

                GetDeviceButtonMapping
                        device: DEVICE
                        nmap: CARD8
                =>
                        map_return: LISTofCARD8

   Errors: Device, Match

The GetDeviceButtonMapping function returns the current mapping
of the buttons on the specified device. Elements of the list
are indexed starting from one. The length of the list indicates
the number of physical buttons. The nominal mapping is the
identity mapping map[i]=i.

nmap indicates the number of elements in the map_return array.
Only the first nmap entries will be copied by the library into
the map_return array.

To set the button mapping for an extension device, use
SetDeviceButtonMapping.

                SetDeviceButtonMapping
                        device: DEVICE
                        map: LISTofCARD8
                        nmap: CARD8
                =>
                        status: CARD8

   Errors: Device, Match, Value

The SetDeviceButtonMapping function sets the mapping of the
specified device and causes the X server to generate a
DeviceMappingNotify event on a status of MappingSuccess.
Elements of the list are indexed starting from one. The length
of the list, specified in nmap, must be the same as
GetDeviceButtonMapping would return. Otherwise,
SetDeviceButtonMapping generates a Value error. A zero element
disables a button, and elements are not restricted in value by
the number of physical buttons. If any of the buttons to be
altered are in the down state, the status reply is MappingBusy
and the mapping is not changed.

In servers supporting XI 1.x, no two elements can have the same
nonzero value. Otherwise, this function generates a Value
error.

2.21 Obtaining The State Of A Device
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To obtain vectors that describe the state of the keys, buttons
and valuators of an extension device, use QueryDeviceState.

                QueryDeviceState
                        device: DEVICE
                =>
                        device-id: CARD8
                        data: LISTofINPUTCLASS

where

                INPUTCLASS: {VALUATOR, BUTTON, KEY}
                CLASS VALUATOR:
                            [class: CARD8
                             num_valuators: CARD8
                             mode: CARD8
                             #x01 device mode (0 = Relative, 1 = Absolute)
                             #x02 proximity state (0 = InProximity, 1 = OutOfProximity)
                             valuators: LISTofINT32]
                CLASS BUTTON:
                            [class: CARD8
                             num_buttons: CARD8
                             buttons: LISTofCARD8]
                CLASS KEY:
                            [class: CARD8
                             num_keys: CARD8
                             keys: LISTofCARD8]

   Errors: Device

The QueryDeviceState request returns the current logical state
of the buttons, keys, and valuators on the specified input
device. The buttons and keys arrays, byte N (from 0) contains
the bits for key or button 8N to 8N+7 with the least
significant bit in the byte representing key or button 8N.

If the device has valuators, a bit in the mode field indicates
whether the device is reporting Absolute or Relative data. If
it is reporting Absolute data, the valuators array will contain
the current value of the valuators. If it is reporting Relative
data, the valuators array will contain undefined data.

If the device reports proximity information, a bit in the mode
field indicates whether the device is InProximity or
OutOfProximity.

2.22 Listing Device Properties
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Introduced with XI 1.5

            ListDeviceProperties
                     deviceid: CARD8
            =>
                     nAtoms: CARD16
                     Atoms: LISTofATOM

   Errors: Device

Each device can store an arbitrary number of properties. These
properties can be allocated by either the client or the driver.
The client can change device properties and the server
guarantees that the device driver is notified about a change of
the device's properties.

ListDeviceProperties returns all properties of a device. The
client is expected to retrieve details about the properties it
is interested in separately.

2.23 Getting a Device Property
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Introduced with XI 1.5

            GetDeviceProperty:
                     property: ATOM
                     type: ATOM
                     longOffset: CARD32
                     longLength: CARD32
                     deviceid: CARD8
                     delete: BOOL
            =>
                     propertyType: ATOM
                     bytesAfter: CARD32
                     nItems: CARD32
                     format: CARD8
                     deviceid: CARD8
                     data: [LISTofCARD8]

   Errors: Atom, Device, Value, Access

Retrieve the value for a property. If the property does not
exist, propertyType is None and all other fields are undefined.

If type is not AnyPropertyType and does not match the
property's actual type, the propertyType, bytesAfter, and
format are returned but not the actual data.

longOffset and longLength specify the offset and length
respectively in 32-bit multiples of the data to retrieve.

If delete is True, the property is deleted after querying its
data. If the property cannot be deleted, a BadAccess error is
returned.

propertyType returns the atom identifier that defines the
actual type of the property.

If bytesAfter is non-zero, it specifies the number of data
4-byte units after the retrieved chunk of data.

format specifies whether the data should be viewed as a list of
8-bit, 16-bit, or 32-bit quantities. Possible values are 8, 16,
and 32. This information allows the X server to correctly
perform byte-swap operations as necessary.

nItem specifies the number of 8-bit, 16-bit, or 32-bit items
returned after the request.

2.24 Changing a Device Property
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Introduced with XI 1.5

            ChangeDeviceProperty:
                     property: ATOM
                     type: ATOM
                     deviceid: CARD8
                     format: CARD8
                     mode: CARD8
                     nUnits: CARD32

   Errors: Atom, Device, Value, Match, Access

Changes the value of a specified property.

The type specifies the atom identifier that defines the type of
the property. If mode is not PropModeReplace, the type must
match the current type of the property or a BadMatch error is
returned.

format specifies whether the data should be viewed as a list of
8-bit, 16-bit, or 32-bit quantities. Possible values are 8, 16,
and 32. This information allows the X server to correctly
perform byte-swap operations as necessary.

If mode is PropModeReplace, a preexising value for this
property is replaced with the new value. If mode is
PropModePrepend or PropModeAppend, the value is prepended or
appended, respectively, to the current value of the property.

nUnits specifies the number of 8-bit, 16-bit, or 32-bit items
supplied after the reply.

Changing a device property results in a
DevicePropertyNotifyEvent being sent to all clients.

2.25 Deleting a Device Property
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Introduced with XI 1.5

            DeleteDeviceProperty:
                     property: ATOM
                     deviceid: CARD8

   Errors: Atom, Device, Match, Access.

Deletes the specified property. If the property cannot be
deleted by the client, a BadAccess error is returned.

3. Events
---------

The input extension creates input events analogous to the core
input events. These extension input events are generated by
manipulating one of the extension input devices.

3.1 Button, Key, and Motion Events
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

            DeviceKeyPress
            DeviceKeyRelease
            DeviceButtonPress,
            DeviceButtonRelease
            DeviceMotionNotify
                    device: CARD8
                    root, event: WINDOW
                    child: Window or None
                    same-screen: BOOL
                    root-x, root-y, event-x, event-y: INT16
                    detail: <see below>
                    state: SETofKEYBUTMASK
                    time: TIMESTAMP

These events are generated when a key, button, or valuator
logically changes state. The generation of these logical
changes may lag the physical changes, if device event
processing is frozen. Note that DeviceKeyPress and
DeviceKeyRelease are generated for all keys, even those mapped
to modifier bits. The “source” of the event is the window the
pointer is in. The window with respect to which the event is
normally reported is found by looking up the hierarchy
(starting with the source window) for the first window on which
any client has selected interest in the event. The actual
window used for reporting can be modified by active grabs and
by the focus window.The window the event is reported with
respect to is called the “event” window.

The root is the root window of the “source” window, and root-x
and root-y are the pointer coordinates relative to root's
origin at the time of the event. Event is the “event” window.
If the event window is on the same screen as root, then event-x
and event-y are the pointer coordinates relative to the event
window's origin. Otherwise, event-x and event-y are zero. If
the source window is an inferior of the event window, then
child is set to the child of the event window that is an
ancestor of (or is) the source window. Otherwise, it is set to
None.

The state component gives the logical state of the buttons on
the X pointer and modifier keys on the core X keyboard just
before the event.

The detail component type varies with the event type:
Event               Component
DeviceKeyPress      KEYCODE
DeviceKeyRelease    KEYCODE
DeviceButtonPress   BUTTON
DeviceButtonRelease BUTTON
DeviceMotionNotify  { Normal , Hint }

The granularity of motion events is not guaranteed, but a
client selecting for motion events is guaranteed to get at
least one event when a valuator changes. If DeviceMotionHint is
selected, the server is free to send only one
DeviceMotionNotify event (with detail Hint) to the client for
the event window, until either a key or button changes state,
the pointer leaves the event window, or the client issues a
QueryDeviceState or GetDeviceMotionEvents request.

3.2 DeviceValuator Event
~~~~~~~~~~~~~~~~~~~~~~~~

                DeviceValuator
                        device: CARD8
                        device_state: SETofKEYBUTMASK
                        num_valuators: CARD8
                        first_valuator: CARD8
                        valuators: LISTofINT32

DeviceValuator events are generated to contain valuator
information for which there is insufficient space in DeviceKey,
DeviceButton, DeviceMotion, and Proximity wire events. For
events of these types, a second event of type DeviceValuator
follows immediately. The library combines these events into a
single event that a client can receive via XNextEvent.
DeviceValuator events are not selected for by clients, they
only exist to contain information that will not fit into some
event selected by clients.

The device_state component gives the state of the buttons and
modifiers on the device generating the event.

Extension motion devices may report motion data for a variable
number of axes. The valuators array contains the values of all
axes reported by the device. If more than 6 axes are reported,
more than one DeviceValuator event will be sent by the server,
and more than one DeviceKey, DeviceButton, DeviceMotion, or
Proximity event will be reported by the library. Clients should
examine the corresponding fields of the event reported by the
library to determine the total number of axes reported, and the
first axis reported in the current event. Axes are numbered
beginning with zero.

For Button, Key and Motion events on a device reporting
absolute motion data the current value of the device's
valuators is reported. For devices that report relative data,
Button and Key events may be followed by a DeviceValuator event
that contains 0s in the num_valuators field. In this case, only
the device_state component will have meaning.

3.3 Device Focus Events
~~~~~~~~~~~~~~~~~~~~~~~

                DeviceFocusIn
                DeviceFocusOut
                        device: CARD8
                        time: TIMESTAMP
                        event: WINDOW
                        mode: { Normal, WhileGrabbed, Grab, Ungrab}
                        detail: { Ancestor, Virtual, Inferior, Nonlinear,
                                  NonlinearVirtual, Pointer, PointerRoot, None}

These events are generated when the input focus changes and are
reported to clients selecting DeviceFocusChange for the
specified device and window. Events generated by SetDeviceFocus
when the device is not grabbed have mode Normal. Events
generated by SetDeviceFocus when the device is grabbed have
mode WhileGrabbed. Events generated when a device grab activates
have mode Grab, and events generated when a device grab
deactivates have mode Ungrab.

All DeviceFocusOut events caused by a window unmap are
generated after any UnmapNotify event, but the ordering of
DeviceFocusOut with respect to generated EnterNotify,
LeaveNotify, VisibilityNotify and Expose events is not
constrained.

DeviceFocusIn and DeviceFocusOut events are generated for focus
changes of extension devices in the same manner as focus events
for the core devices are generated.

3.4 Device State Notify Event
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                DeviceStateNotify
                time: TIMESTAMP
                device: CARD8
                num_keys: CARD8
                num_buttons: CARD8
                num_valuators: CARD8
                classes_reported: CARD8 {SetOfDeviceMode | SetOfInputClass}
                    SetOfDeviceMode:
                        #x80 ProximityState 0 = InProxmity, 1 = OutOfProximity
                        #x40 Device Mode (0 = Relative, 1 = Absolute)
                    SetOfInputClass: #x04 reporting valuators
                        #x02 reporting buttons
                        #x01 reporting keys
                buttons: LISTofCARD8
                keys: LISTofCARD8
                valuators: LISTofCARD32

This event reports the state of the device just as in the
QueryDeviceState request. This event is reported to clients
selecting DeviceStateNotify for the device and window and is
generated immediately after every EnterNotify and
DeviceFocusIn. If the device has no more than 32 buttons, no
more than 32 keys, and no more than 3 valuators, This event can
report the state of the device. If the device has more than 32
buttons, the event will be immediately followed by a
DeviceButtonStateNotify event. If the device has more than 32
keys, the event will be followed by a DeviceKeyStateNotify
event. If the device has more than 3 valuators, the event will
be followed by one or more DeviceValuator events.

3.5 Device KeyState and ButtonState Notify Events
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                DeviceKeyStateNotify
                        device: CARD8
                        keys: LISTofCARD8
                DeviceButtonStateNotify
                        device: CARD8
                        buttons: LISTofCARD8

These events contain information about the state of keys and
buttons on a device that will not fit into the
DeviceStateNotify wire event. These events are not selected by
clients, rather they may immediately follow a DeviceStateNotify
wire event and be combined with it into a single
DeviceStateNotify client event that a client may receive via
XNextEvent.

3.6 DeviceMappingNotify Event
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                DeviceMappingNotify
                        time: TIMESTAMP
                        device: CARD8
                        request: CARD8
                        first_keycode: CARD8
                        count: CARD8

This event reports a change in the mapping of keys, modifiers,
or buttons on an extension device. This event is reported to
clients selecting DeviceMappingNotify for the device and window
and is generated after every client SetDeviceButtonMapping,
ChangeDeviceKeyMapping, or ChangeDeviceModifierMapping request.

3.7 ChangeDeviceNotify Event
~~~~~~~~~~~~~~~~~~~~~~~~~~~~

                ChangeDeviceNotify
                        device: CARD8
                        time: TIMESTAMP
                        request: CARD8

This event reports a change in the physical device being used
as the core X keyboard or X pointer device. ChangeDeviceNotify
events are reported to clients selecting ChangeDeviceNotify for
the device and window and is generated after every client
ChangeKeyboardDevice or ChangePointerDevice request.

3.7 Proximity Events
~~~~~~~~~~~~~~~~~~~~

                ProximityIn
                ProximityOut
                        device: CARD8
                        root, event: WINDOW
                        child: Window or None
                        same-screen: BOOL
                        root-x, root-y, event-x, event-y: INT16
                        state: SETofKEYBUTMASK
                        time: TIMESTAMP
                        device-state: SETofKEYBUTMASK
                        axis-count: CARD8
                        first-axis: CARD8
                        axis-data: LISTofINT32

These events are generated by some devices (such as graphics
tablets or touchscreens) to indicate that a stylus has moved
into or out of contact with a positional sensing surface.

The “source” of the event is the window the pointer is in. The
window with respect to which the event is normally reported is
found by looking up the hierarchy (starting with the source
window) for the first window on which any client has selected
interest in the event. The actual window used for reporting can
be modified by active grabs and by the focus window.The window
the event is reported with respect to is called the “event”
window.

The root is the root window of the “source” window, and root-x
and root-y are the pointer coordinates relative to root's
origin at the time of the event. Event is the “event” window.
If the event window is on the same screen as root, then event-x
and event-y are the pointer coordinates relative to the event
window's origin. Otherwise, event-x and event-y are zero. If
the source window is an inferior of the event window, then
child is set to the child of the event window that is an
ancestor of (or is) the source window. Otherwise, it is set to
None. The state component gives the logical state of the
buttons on the core X pointer and modifier keys on the core X
keyboard just before the event. The device-state component
gives the state of the buttons and modifiers on the device
generating the event.

3.8 DevicePresenceEvents
~~~~~~~~~~~~~~~~~~~~~~~~

Introduced with XI 1.4.

                DevicePresence
                        time: TIMESTAMP
                        devchange: BYTE
                            #x00: DeviceAdded
                            #x01: DeviceRemoved
                            #x02: DeviceEnabled
                            #x03: DeviceDisabled
                            #x04: DeviceUnrecoverable
                            #x05: DeviceControlChanged
                        deviceid: BYTE
                        control: CARD16

DevicePresence events are sent when the server adds or removes,
or enables or disables an input device. The client is expected
to query the server for the list of input devices using the
ListInputDevices request to obtain the updated list of input
devices. DevicePresence events are also sent when a control on
the device has been changed.

The devchange field specifies the type of operation. In case of
DeviceAdded, a new device has been added to the server, but
this device does not yet send events. If devchange is set to
DeviceEnabled, the device is enabled and will generate events.
If the field is DeviceDisabled or DeviceRemoved, the given
device is disabled and stops sending events or was removed from
the server, respectively. If the field is DeviceUnrecoverable,
an IO-error has occurred on the device and the device is
forcibly disabled and removed by the server. If devchange is
DeviceControlChanged, control specifies the type of control
that has been changed.

3.9 DevicePropertyNotifyEvent
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Introduced with XI 1.5.

                DevicePropertyNotifyEvent
                        deviceid: CARD8
                        state: CARD8
                        time: TIMESTAMP
                        atom: ATOM

A DevicePropertyNotifyEvent is sent to all clients when a
property on the device is created, deleted, or changes value.

The deviceid specifies the device which's property has been
modified.

The atom specifies the named identifier of the property that
has been altered.

If state is PropertyNewValue, the given property has a new
value or has been newly created. If state is PropertyDeleted,
the given property has been deleted.