# 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

    Copyright © 1989, 1990, 1991 by Hewlett-Packard Company and
    Ardent Computer

    Permission to use, copy, modify, and distribute this
    documentation for any purpose and without fee is hereby
    granted, provided that the above copyright notice and this
    permission notice appear in all copies. Ardent and
    Hewlett-Packard make no representations about the suitability
    for any purpose of the information in this document. It is
    provided "as is" without express or implied warranty. Copyright
    © 1989, 1990, 1991, 1992 X Consortium

    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the “Software”), to deal in the Software without
    restriction, including without limitation the rights to use,
    copy, modify, merge, publish, distribute, sublicense, and/or
    sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following
    conditions:

    The above copyright notice and this permission notice shall be
    included in all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE
    FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
    OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.

    Except as contained in this notice, the name of the X
    Consortium shall not be used in advertising or otherwise to
    promote the sale, use or other dealings in this Software
    without prior written authorization from the X Consortium. X
    Window System is a trademark of The Open Group.

    Copyright © 2008 by Peter Hutterer

    Permission is hereby granted, free of charge, to any person
    obtaining a copy of this software and associated documentation
    files (the "Software"), to deal in the Software without
    restriction, including without limitation the rights to use,
    copy, modify, merge, publish, distribute, sublicense, and/or
    sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following
    conditions:

    The above copyright notice and this permission notice
    (including the next paragraph) shall be included in all copies
    or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
    EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
    OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
    NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
    HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
    FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
    OTHER DEALINGS IN THE SOFTWARE.

## 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
            struture.

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 specifed 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 specifed 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 indicies 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 occured 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.