XSelectInput - select input events

display   Specifies the connection to the X server.

       event_mask
                 Specifies the event mask.

       w         Specifies the window whose events you are interested in.

       The  XSelectInput  function  requests  that  the X server report the events associated with the specified
       event mask.  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.

       Setting  the event-mask attribute of a window overrides any previous call for the same window but not for
       other clients.  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 CirculateRequest, ConfigureRequest, or MapRequest events, which
            are associated with the event mask SubstructureRedirectMask.

       •    Only one client at a time can select a ResizeRequest event, which is associated with the event  mask
            ResizeRedirectMask.

       •    Only  one  client  at a time can select a ButtonPress event, which is associated with the event mask
            ButtonPressMask.

       The server reports the event to all interested clients.

       XSelectInput can generate a BadWindow error.

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

       XSelectInput - select input events

Xlib-CLanguageXInterface

X Version 11                                      libX11 1.8.12                                  XSelectInput(3)

       int XSelectInput(Display *display, Window w, long event_mask);