XGRABDEVICE(3)

XGRABDEVICE(3) |  | XGRABDEVICE(3)

# NAME

XGrabDevice, XUngrabDevice - grab/release the specified extension device

# SYNOPSIS

    #include <X11/extensions/XInput.h>

    int XGrabDevice( Display *display,

                     XDevice* device,

                     Window grab_window,

                     Bool owner_events,

                     int event_count,

                     XEventClass *event_list,

                     int this_device_mode,

                     int other_devices_mode,

                     Time time);

    int XUngrabDevice( Display *display,

                       XDevice *device,

                       Time time);

    display

           Specifies the connection to the X server.

    device

           Specifies the device to be grabbed or released.

    grab_window

           Specifies the id of a window to be associated with the

           device.

    owner_events

           Specifies a Boolean value that indicates whether

           the events from the device are to be reported as usual or

           reported with respect to the grab window if selected by

           the event list.

    event_count

           Specifies the number of elements in the event_list

           array.

    event_list

           Specifies a pointer to a list of event classes that

           indicates which events the client wishes to receive.

           These event classes must have been obtained specifying

           the device being grabbed.

    this_device_mode

           Specifies further processing of events from this

           device. You can pass GrabModeSync or GrabModeAsync.

    other_devices_mode

           Specifies further processing of events from other

           devices. You can pass GrabModeSync or GrabModeAsync.

    time

           Specifies the time. You can pass either a timestamp or

           CurrentTime.

# DESCRIPTION

    The XGrabDevice request actively grabs control of the device
    and generates DeviceFocusIn and DeviceFocusOut events. Further
    device events are reported only to the grabbing
    client. XGrabDevice overrides any active device grab by this
    client. event_list is a pointer to a list of event classes.
    This list indicates which events the client wishes to receive
    while the grab is active. If owner_events is False, all
    generated device events are reported with respect to
    grab_window if selected. If owner_events is True and if a
    generated device 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 specified in the event_list.

    If the this_device_mode argument is GrabModeAsync, device event
    processing continues as usual. If the device is currently
    frozen by this client, then processing of device events is
    resumed. If the this_device_mode argument is GrabModeSync, the
    state of the device (as seen by client applications) appears to
    freeze, and the X server generates no further device events
    until the grabbing client issues a releasing XAllowDeviceEvents
    call or until the device grab is released. Actual device
    changes are not lost while the device is frozen; they are
    simply queued in the server for later processing.

    If other_devices_mode is GrabModeAsync, processing of events
    from other devices is unaffected by activation of the grab. If
    other_devices_mode is GrabModeSync, the state of all devices
    except the grabbed device (as seen by client applications)
    appears to freeze, and the X server generates no further events
    from those devices until the grabbing client issues a releasing
    XAllowDeviceEvents call or until the device grab is released.
    Actual events are not lost while the devices are frozen; they
    are simply queued in the server for later processing.

    If the device is actively grabbed by some other client,
    XGrabDevice fails and returns AlreadyGrabbed. If grab_window is
    not viewable, it fails and returns GrabNotViewable. If the
    device is frozen by an active grab of another client, it fails
    and returns GrabFrozen. If the specified time is earlier than
    the last-device-grab time or later than the current X server
    time, it fails and returns GrabInvalidTime. Otherwise, the
    last-device-grab time is set to the specified time
    (CurrentTime is replaced by the current X server time).

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

    XGrabDevice can generate BadClass, BadDevice, BadValue, and
    BadWindow errors.

    The XUngrabDevice request releases the device and any queued
    events if this client has it actively grabbed from either
    XGrabDevice or XGrabDeviceKey. If other devices are frozen by
    the grab, XUngrabDevice thaws them. XUngrabDevice does not
    release the device and any queued events if the specified time
    is earlier than the last-device-grab time or is later than the
    current X server time. It also generates DeviceFocusIn and
    DeviceFocusOut events. The X server automatically performs an
    UngrabDevice request if the event window for an active device
    grab becomes not viewable.

    XUngrabDevice can generate a BadDevice error.

# 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.

# SEE ALSO

    XAllowDeviceEvents(3), XGrabDeviceButton(3), XGrabDeviceKey(3)

09/05/2024 |