XSelectExtensionEvent, XGetSelectedExtensionEvents - select extension
   events, get the list of currently selected extension events


   #include <X11/extensions/XInput.h>

   XSelectExtensionEvent( Display *display,
                          Window w,
                          XEventClass *event_list,
                          int event_count);

   XGetSelectedExtensionEvents( Display *display,
                                Window w,
                                int *this_client_event_count_return,
                                XEventClass **this_client_event_list_return,
                                int *all_clients_event_count_return,
                                XEventClass **all_clients_event_list_return);

          Specifies the connection to the X server.

          Specifies the window whose events you are interested in.

          Specifies the list of event classes that describe the
          events you are interested in.

          Specifies the count of event classes in the event list.

          Returns the count of event classes selected by this

          Returns a pointer to the list of event classes selected
          by this client.

          Returns the count of event classes selected by all

          Returns a pointer to the list of event classes selected
          by all clients.


       The XSelectExtensionEvent request causes the X server to report
       the events associated with the specified list of event classes.
       Initially, X will not report any of these events. Events are
       reported relative to a window. If a window is not interested in
       a device event, it usually propagates to the closest ancestor
       that is interested, unless the do_not_propagate mask prohibits

       Multiple clients can select for the same events on the same
       window with the following restrictions:
         * Multiple clients can select events on the same window
           because their event masks are disjoint. When the X server
           generates an event, it reports it to all interested
         * Only one client at a time can select a DeviceButtonPress
           event with automatic passive grabbing enabled, which is
           associated with the event class DeviceButtonPressGrab. To
           receive DeviceButtonPress events without automatic passive
           grabbing, use event class DeviceButtonPress but do not
           specify event class DeviceButtonPressGrab.

       The server reports the event to all interested clients.

       Information contained in the XDevice structure returned by
       XOpenDevice is used by macros to obtain the event classes that
       clients use in making XSelectExtensionEvent requests. Currently
       defined macros include DeviceKeyPress, DeviceKeyRelease,
       DeviceButtonPress, DeviceButtonRelese, DeviceMotionNotify,
       DeviceFocusIn, DeviceFocusOut, ProximityIn, ProximityOut,
       DeviceStateNotify, DeviceMappingNotify, ChangeDeviceNotify,
       DevicePointerMotionHint, DeviceButton1Motion,
       DeviceButton2Motion, DeviceButton3Motion, DeviceButton4Motion,
       DeviceButton5Motion, DeviceButtonMotion, DeviceOwnerGrabButton,
       DeviceButtonPressGrab, and NoExtensionEvent.

       To obtain the proper event class for a particular device, one
       of the above macros is invoked using the XDevice structure for
       that device. For example,
                    DeviceKeyPress (*device, type, eventclass);

       returns the DeviceKeyPress event type and the eventclass for
       selecting DeviceKeyPress events from this device.

       XSelectExtensionEvent can generate a BadWindow or BadClass
       error. The XGetSelectedExtensionEvents request reports the
       extension events selected by this client and all clients for
       the specified window. This request returns pointers to two
       XEventClass arrays. One lists the input extension events
       selected by this client from the specified window. The other
       lists the event classes selected by all clients from the
       specified window. You should use XFree to free these two

       XGetSelectedExtensionEvents can generate a BadWindow error.


              A value for a Window argument does not name a defined

              A value for an XEventClass is invalid.

                              03/09/2013           XSELECTEXTENSIONEVEN(3)


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