XGrabDevice(3X11)
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 nor-
mally; 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 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 XAl-
lowDeviceEvents 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 Grab-
NotViewable. 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. XUn-
grabDevice 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 UngrabDe-
vice 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 speci-
fied 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 spe-
cific 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) XGrabDe-
viceKey(3X)
Programming With Xlib