.\}

The XGrabDeviceButton request establishes a passive grab. In
the future, the device is actively grabbed (as for XGrabDevice,
the last-grab time is set to the time at which the button was
pressed (as transmitted in the DeviceButtonPress event), and
the DeviceButtonPress event is reported if all of the following
conditions are true:
 * The device is not grabbed, and the specified button is
 logically pressed when the specified modifier keys are
 logically down on the specified 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
XGrabDevice. The active grab is terminated automatically when
the logical state of the device has all buttons released
(independent of the logical state of the modifier keys).

.\}

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 combinations on the same window. A
modifiers of AnyModifier 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 AnyButton 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.

.\}

A modifier_device of NULL indicates that the X keyboard is to
be used as the modifier_device.

.\}

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

.\}

XGrabDeviceButton can generate BadClass, BadDevice, BadMatch,
BadValue, and BadWindow errors..P The XUngrabDeviceButton
request releases the passive grab for a button/modifier
combination on the specified window if it was grabbed by this
client. A modifier of AnyModifier is equivalent to issuing the
ungrab request for all possible modifier combinations,
including the combination of no modifiers. A button of
AnyButton is equivalent to issuing the request for all possible
buttons. XUngrabDeviceButton has no effect on an active grab.

.\}

A modifier_device of NULL indicates that the X keyboard should
be used as the modifier_device.

.\}

XUngrabDeviceButton can generate BadDevice, BadMatch, BadValue
and BadWindow errors.

.\}

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.

.\}

BadMatch
 This error may occur if an XGrabDeviceButton request was
 made specifying a device that has no buttons, or
 specifying a modifier device that has no keys.

.\}

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.

.\}

XAllowDeviceEvents(libmansuffix), XGrabDevice(libmansuffix), XGrabDeviceKey(libmansuffix)