NAME

       Tk_CreateClientMessageHandler,   Tk_DeleteClientMessageHandler   -   associate   procedure
       callback with ClientMessage type X events

SYNOPSIS

       #include <tk.h>

       Tk_CreateClientMessageHandler(proc)

       Tk_DeleteClientMessageHandler(proc)

ARGUMENTS

       Tk_ClientMessageProc *proc (in)           Procedure to invoke whenever a  ClientMessage  X
                                                 event occurs on any display.
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DESCRIPTION

       Tk_CreateClientMessageHandler  arranges  for  proc  to be invoked in the future whenever a
       ClientMessage   X    event    occurs    that    is    not    handled    by    WM_PROTOCOL.
       Tk_CreateClientMessageHandler  is  intended  for use by applications which need to watch X
       ClientMessage events, such as drag and drop applications.

       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 Tcl_DoOneEvent or Tk_MainLoop).

       Proc should have arguments and result that match the type Tk_ClientMessageProc:
              typedef int Tk_ClientMessageProc(
                      Tk_Window tkwin,
                      XEvent *eventPtr);
       The tkwin parameter to proc is  the  Tk  window  which  is  associated  with  this  event.
       EventPtr is a pointer to the X event.

       Whenever an X ClientMessage event is processed by Tk_HandleEvent, the proc is called if it
       was not handled as a WM_PROTOCOL.  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 ClientMessage event handlers, each one is called for each event,  in
       the order in which they were established.

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

KEYWORDS

       bind, callback, event, handler