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.

                                            09/15/2021                    XSELECTEXTENSIONEVEN(3)