HPUX CrtGenHdlr[3]

 Tk_CreateGenericHandler(3)          Tk           Tk_CreateGenericHandler(3)

 Tk Library Procedures                                 Tk Library Procedures





 ___________________________________________________________________________

 NAME
      Tk_CreateGenericHandler, Tk_DeleteGenericHandler - associate procedure
      callback with all X events

 SYNOPSIS
      #include <tk.h>

      Tk_CreateGenericHandler(proc, clientData)

      Tk_DeleteGenericHandler(proc, clientData)

 ARGUMENTS
      Tk_GenericProc   *proc        (in)      Procedure to  invoke  whenever
                                              any  X  event  occurs  on  any
                                              display.

      ClientData       clientData   (in)      Arbitrary  one-word  value  to
                                              pass to proc.
 ___________________________________________________________________________


 DESCRIPTION
      Tk_CreateGenericHandler arranges for proc to be invoked in the  future
      whenever  any  X  event  occurs.   This  mechanism is not intended for
      dispatching X  events  on  windows  managed  by  Tk  (you  should  use
      Tk_CreateEventHandler  for  this purpose).  Tk_CreateGenericHandler is
      intended for other purposes, such  as  tracing  X  events,  monitoring
      events  on windows not owned by Tk, accessing X-related libraries that
      were not originally designed for use with Tk, and so on.

      The callback to proc will be made by  Tk_HandleEvent;  this  mechanism
      only works in programs that dispatch events through Tk_HandleEvent (or
      through  other  Tk  procedures  that  call  Tk_HandleEvent,  such   as
      Tk_DoOneEvent or Tk_MainLoop).

      Proc  should  have  arguments  and  result   that   match   the   type
      Tk_GenericProc:
           typedef int Tk_GenericProc(
                ClientData clientData,
                XEvent *eventPtr);
      The clientData parameter to proc is a copy of the clientData  argument
      given  to  Tk_CreateGenericHandler  when  the  callback  was  created.
      Typically,  clientData  points  to   a   data   structure   containing
      application-specific information about how to handle events.  EventPtr
      is a pointer to the X event.

      Whenever an X event is processed by Tk_HandleEvent,  proc  is  called.



                                    - 1 -        Formatted:  August 11, 1996






 Tk_CreateGenericHandler(3)          Tk           Tk_CreateGenericHandler(3)

 Tk Library Procedures                                 Tk Library Procedures





      The  return  value  from  proc is normally 0.  A non-zero return value
      indicates that the event is not to be handled further; that  is,  proc
      has done all processing that is to be allowed for the event.

      If there are multiple generic event handlers, each one is  called  for
      each event, in the order in which they were established.

      Tk_DeleteGenericHandler may be called to delete  a  previously-created
      generic  event handler:  it deletes each handler it finds that matches
      the proc and clientData arguments.  If no such  handler  exists,  then
      Tk_DeleteGenericHandler  returns  without doing anything.  Although Tk
      supports it, it's probably a bad idea to have more than  one  callback
      with the same proc and clientData arguments.

      Establishing a generic event handler does nothing to ensure  that  the
      process  will  actually receive the X events that the handler wants to
      process.  For example, it is the  caller's  responsibility  to  invoke
      XSelectInput to select the desired events, if that is necessary.

 KEYWORDS
      bind, callback, event, handler































                                    - 2 -        Formatted:  August 11, 1996