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XGrabDevice, XUngrabDevice - grab/release the specified
- int XGrabDevice(Display *display, XDevice *device, Windowgrab_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
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
- Specifies the connection to the X
- 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.
further processing of events from other devices. You can pass GrabModeSync
- Specifies the time. You can pass either a timestamp
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
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.
generate a BadDevice error.
- 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 argument defined as a set of alternatives can generate
- A value for a Window argument does not name a defined
Programming With Xlib
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