XSETDEVICEFOCUS(3)

XSETDEVICEFOCUS(3) |  | XSETDEVICEFOCUS(3)

# NAME

XSetDeviceFocus, XGetDeviceFocus - control extension input device focus

# SYNOPSIS

    #include <X11/extensions/XInput.h>

    XSetDeviceFocus( Display *display,

                     XDevice *device,

                     Window focus,

                     int revert_to,

                     Time time);

    XGetDeviceFocus( Display *display,

                     XDevice *device,

                     Window *focus_return,

                     int *revert_to_return,

                     int * time_return);

Arguments

    display

           Specifies the connection to the X server.

    device

           Specifies the device whose focus is to be queried or

           changed.

    focus

           Specifies the window, PointerRoot, FollowKeyboard, or

           None.

    focus_return

           Returns the focus window, PointerRoot, FollowKeyboard, or

           None.

    revert_to

           Specifies where the input focus reverts to if the window

           becomes not viewable. You can pass RevertToParent,

           RevertToPointerRoot, RevertToFollowKeyboard, or

           RevertToNone.

    revert_to_return

           Returns the current focus state RevertToParent,

           RevertToPointerRoot, RevertToFollowKeyboard, or

           RevertToNone.

    time_return

           Returns the last_focus_time for the device.

    time

           Specifies the time. You can pass either a timestamp or

           CurrentTime.

# DESCRIPTION

    The XSetDeviceFocus request changes the focus of the specified
    device and its last-focus-change time. It has no effect if the
    specified time is earlier than the current 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 CurrentTime
    is replaced by the current X server time). XSetDeviceFocus
    causes the X server to generate DeviceFocusIn and
    DeviceFocusOut events.

    Depending on the focus argument, the following occurs:

      * If focus is None , all device events are discarded until a

        new focus window is set, and the revert_to argument is

        ignored.

      * If focus is a window, it becomes the device's focus window.

        If a generated device event would normally be reported to

        this window or one of its inferiors, the event is reported

        as usual. Otherwise, the event is reported relative to the

        focus window.

      * If focus is PointerRoot, the focus window is dynamically

        taken to be the root window of whatever screen the pointer

        is on at each event from the specified device. In this

        case, the revert_to argument is ignored.

      * If focus is FollowKeyboard, the focus window is dynamically

        taken to be the window to which the X keyboard focus is set

        at each input event.

    The specified focus window must be viewable at the time
    XSetDeviceFocus is called, or a BadMatch error results. If the
    focus window later becomes not viewable, the X server evaluates
    the revert_to argument to determine the new focus window as
    follows:

      * If revert_to is RevertToParent, the focus reverts to the

        parent (or the closest viewable ancestor), and the new

        revert_to value is taken to be RevertToNone.

      * If revert_to is RevertToPointerRoot,

        RevertToFollowKeyboard, or RevertToNone, the focus reverts

        to PointerRoot, FollowKeyboard, or None, respectively.

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

    Input extension devices are not required to support the ability
    to be focused. Attempting to set the focus of a device that
    does not support this request will result in a BadMatch error.
    Whether or not given device can support this request can be
    determined by the information returned by XOpenDevice. For
    those devices that support focus, XOpenDevice will return an
    XInputClassInfo structure with the input_class field equal to
    the constant FocusClass (defined in the file XI.h).

    XSetDeviceFocus can generate BadDevice, BadMatch, BadValue, and
    BadWindow errors.

    The XGetDeviceFocus request returns the focus window and the
    current focus state.

    Not all input extension devices can be focused. Attempting to
    query the focus state of a device that can't be focused results
    in a BadMatch error. A device that can be focused returns
    information for input Class Focus when an XOpenDevice request
    is made.

    XGetDeviceFocus can generate BadDevice, and BadMatch errors.

# DIAGNOSTICS

    BadDevice

           An invalid device was specified. The specified device

           does not exist or has not been opened by this client via

           XOpenInputDevice. This error may also occur if the

           specified device is the X keyboard or X pointer device.

    BadValue

           Some numeric value falls outside the range of values

           accepted by the request. Unless a specific range is

           specified for an argument, the full range defined by the

           argument's type is accepted. Any argument defined as a

           set of alternatives can generate this error.

    BadWindow

           A value for a Window argument does not name a defined

           Window.

    BadMatch

           This error may occur if an XGetDeviceFocus or

           XSetDeviceFocus request was made specifying a device

           that the server implementation does not allow to be

           focused.

09/05/2024 |