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