XIGrabButton, XIGrabKeycode, XIGrabTouchBegin, XIGrabPinchGestureBegin,
XIGrabSwipeTouchBegin establish a passive grab.
The modifier device for a button grab is the paired master device
if deviceid specifies a master pointer. Otherwise, the modifier
device is the device specified with deviceid. In the future,
the device is actively grabbed (as for XIGrabDevice, the
last-grab time is set to the time at which the button or keycode
was pressed and the XI_ButtonPress or XI_KeyPress event is
reported if all of the following conditions are true:


  * The device is not grabbed, and the specified button or


    keycode is logically pressed, a touch or a gesture event occurs when the


    specified modifier keys are logically down on the modifier device


    and no other buttons or modifier keys are logically down.


  * Either the grab window is an ancestor of (or is) the focus


    window, OR the grab window is a descendent of the focus


    window and contains the device.


  * A passive grab on the same button/modifier combination does


    not exist on any ancestor of grab_window.

The interpretation of the remaining arguments is as for
XIGrabDevice. The active grab is terminated automatically when
the logical state of the device has all buttons or keys
released (independent of the logical state of the modifier
keys).

If the device is an attached slave device, the device is
automatically detached from the master device when the grab
activates and reattached to the same master device when the
grab deactivates. If the master device is removed while the
device is floating as a result of a grab, the device remains
floating once the grab deactivates.

Note that the logical state of a device (as seen by client
applications) may lag the physical state if device event
processing is frozen.

This request overrides all previous grabs by the same client on
the same button/modifier or keycode/modifier combinations on the
same window. A modifiers of XIAnyModifier is equivalent to
issuing the grab request for all possible modifier combinations
(including the combination of no modifiers). It is not required
that all modifiers specified have currently assigned KeyCodes.
A button of XIAnyButton is equivalent to issuing the request
for all possible buttons. Otherwise, it is not required that
the specified button currently be assigned to a physical
button.

If some other client has already issued a XIGrabButton or
XIGrabKeycode with the same button/modifier or keycode/modifier
combination on the same window, a BadAccess error results. When
using XIAnyModifier or XIAnyButton , the request fails
completely, and a XIBadAccess error results (no grabs are
established) if there is a conflicting grab for any
combination. XIGrabButton and XIGrabKeycode have no effect on an
active grab.

On success, XIGrabButton, XIGrabKeycode, XIGrabTouchBegin,
XIGrabPinchGestureBegin and XIGrabSwipeGestureBegin return 0;
If one or more modifier combinations could not be grabbed,
XIGrabButton, XIGrabKeycode, XIGrabTouchBegin, XIGrabPinchGestureBegin
and XIGrabSwipeGestureBegin return the number of
failed combinations and modifiers_inout contains the failed combinations
and their respective error codes.

XIGrabButton, XIGrabKeycode, XIGrabTouchBegin, XIGrabPinchGestureBegin
and XIGrabSwipeGestureBegin can generate BadClass,
BadDevice, BadMatch, BadValue, and BadWindow errors.

XIUngrabButton, XIUngrabKeycode, XIUngrabTouchBegin, XIUngrabPinchGestureBegin
and XIUngrabSwipeGestureBegin release the
passive grab for a button/modifier, keycode/modifier or touch/modifier
combination on the specified window if it was grabbed by this client. A
modifier of XIAnyModifier is equivalent to issuing the ungrab request
for all possible modifier combinations, including the
combination of no modifiers. A button of XIAnyButton is
equivalent to issuing the request for all possible buttons.
XIUngrabButton and XIUngrabKeycode have no effect on an active
grab.

XIUngrabButton, XIUngrabKeycode, XIUngrabTouchBegin,
XIUngrabPinchGestureBegin and XIUngrabSwipeGestureBegin can generate
BadDevice, BadMatch, BadValue and BadWindow errors.

XIGrabButton, XIGrabKeycode, XIGrabTouchBegin and
XIGrabPinchGestureBegin and XIGrabSwipeGestureBegin return the number of
modifier combination that could not establish a passive grab. The
modifiers are returned in modifiers_inout, along with the respective
error for this modifier combination. If XIGrabButton, XIGrabKeycode
or XIGrabTouchBegin return zero, passive grabs with all requested
modifier combinations were established successfully.

BadDevice


       An invalid deviceid was specified.

BadMatch


       This error may occur if XIGrabButton specified a device


       that has no buttons, or XIGrabKeycode specified a device


       that has no keys,


       or XIGrabTouchBegin specified a device that is not touch-capable,


       or XIGrabPinchGestureBegin specified a device that is not gesture-capable,


       or XIGrabSwipeGestureBegin specified a device that is not gesture-capable.

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.

The protocol headers for XI 2.0 did not provide
XIGrabModeAsync or XIGrabModeSync. Use GrabModeSync and
GrabModeAsync instead, respectively.

XIAllowEvents(3)