XGRABDEVICE(3) libXi XGRABDEVICE(3)NAME
XGrabDevice, XUngrabDevice - grab/release the specified extension
device
SYNTAX
#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);
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 theevents from the
deviceare to be reported as usual or reported with respect to the
grab windowif 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
eventsthe client wishes to receive. These event classes must have
beenobtained specifying the device being grabbed.
this_device_mode
Specifies further processing of events from this device.You can pass
GrabModeSyncor GrabModeAsync.
other_devices_mode
Specifies further processing of events from other devices.You can
pass GrabModeSyncor 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 ALSOXAllowDeviceEvents(3),XGrabDeviceButton(3),XGrabDeviceKey(3)
03/04/2009 XGRABDEVICE(3)