XGrabDevice(3X11)XGrabDevice(3X11)NAME
XGrabDevice, XUngrabDevice - grab/release the specified extension
device
SYNOPSIS
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
Specifies the connection to the X server. Specifies the device to be
grabbed or released. Specifies the id of a window to be associated
with the device. 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. Specifies
the number of elements in the event_list array. 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. Specifies further processing of events from this
device. You can pass GrabModeSync or GrabModeAsync. Specifies further
processing of events from other devices. You can pass GrabModeSync or
GrabModeAsync. Specifies the time. You can pass either a timestamp or
CurrentTime.
DESCRIPTION
The XGrabDevice request actively grabs control of the device and gener‐
ates 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 pro‐
cessing 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 gener‐
ates 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 speci‐
fied 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 XGrabDe‐
viceKey. 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
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. 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 argu‐
ment defined as a set of alternatives can generate this error. A value
for a Window argument does not name a defined Window.
SEE ALSOXAllowDeviceEvents(3X11), XGrabDeviceButton(3X11), XGrabDeviceKey(3X11)
Programming With Xlib
XGrabDevice(3X11)
