xref: /xsrc/external/mit/libXi/dist/man/XSelectExtensionEvent.txt

XSELECTEXTENSIONEVENT(libmansuffix)
===================================

NAME
----

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

SYNOPSIS
--------

   #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);

   display
          Specifies the connection to the X server.

   w
          Specifies the window whose events you are interested in.

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

   event_count
          Specifies the count of event classes in the event list.

   this_client_event_count_return
          Returns the count of event classes selected by this
          client.

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

   all_clients_event_count_return
          Returns the count of event classes selected by all
          clients.

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

DESCRIPTION
-----------

   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
   it.

   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
       clients.
     * 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, DeviceButtonRelease, 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
   arrays.

   XGetSelectedExtensionEvents can generate a BadWindow error.

DIAGNOSTICS
-----------

   BadWindow
          A value for a Window argument does not name a defined
          window.

   BadClass
          A value for an XEventClass is invalid.