XGrabDevice
Section: X FUNCTIONS (3X11)
Updated: Release 5
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NAME
XGrabDevice, XUngrabDevice - grab/release the specified extension device
SYNTAX
int XGrabDevice(display, device, grab_window, owner_events, event_count, event_list,
this_device_mode, other_devices_mode, time)
Display *display;
XDevice *device;
Window grab_window;
Bool owner_events;
int event_count;
XEventClass *event_list;
int this_device_mode, other_devices_mode;
Time time;
XUngrabDevice(display, device, time)
Display *display;
XDevice *device;
Time time;
ARGUMENTS
- 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(3X),
XGrabDeviceButton(3X),
XGrabDeviceKey(3X),
Programming With Xlib
Index
- NAME
-
- SYNTAX
-
- ARGUMENTS
-
- DESCRIPTION
-
- DIAGNOSTICS
-
- SEE ALSO
-
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Time: 07:02:31 GMT, May 19, 2025