XGrabDevice
XGrabDevice(3X11) X FUNCTIONS XGrabDevice(3X11)
NAME
XGrabDevice, XUngrabDevice - grab/release the specified extension
device
SYNTAX
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 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 indi-
cates 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 gen-
erates 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
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 XGrab-
DeviceKey. 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 Device-
FocusIn and DeviceFocusOut events. The X server automatically per-
forms 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 speci-
fied 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 spec-
ified for an argument, the full range defined by the argu-
ment’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 Win-
dow.
SEE ALSO
XAllowDeviceEvents(3X), XGrabDeviceButton(3X), XGrabDeviceKey(3X),
Programming With Xlib
XGrabDevice(3X11)
