1Tk_CreateClientMessageHandler(T3k)Library ProceduTrke_sCreateClientMessageHandler(3)
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NAME

8       Tk_CreateClientMessageHandler,  Tk_DeleteClientMessageHandler  -  asso‐
9       ciate procedure callback with ClientMessage type X events
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SYNOPSIS

12       #include <tk.h>
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14       Tk_CreateClientMessageHandler(proc)
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16       Tk_DeleteClientMessageHandler(proc)
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ARGUMENTS

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

25       Tk_CreateClientMessageHandler arranges for proc to be  invoked  in  the
26       future  whenever  a ClientMessage X event occurs that is not handled by
27       WM_PROTOCOL.  Tk_CreateClientMessageHandler  is  intended  for  use  by
28       applications  which  need to watch X ClientMessage events, such as drag
29       and drop applications.
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31       The callback to proc will be made  by  Tk_HandleEvent;  this  mechanism
32       only  works in programs that dispatch events through Tk_HandleEvent (or
33       through  other  Tk  procedures  that  call  Tk_HandleEvent,   such   as
34       Tk_DoOneEvent or Tk_MainLoop).
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36       Proc should have arguments and result that match the type Tk_ClientMes‐
37       sageProc:
38              typedef int Tk_ClientMessageProc(
39                      Tk_Window tkwin,
40                      XEvent *eventPtr);
41       The tkwin parameter to proc is the Tk window which is  associated  with
42       this event.  EventPtr is a pointer to the X event.
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44       Whenever  an  X ClientMessage event is processed by Tk_HandleEvent, the
45       proc is called if it was not handled  as  a  WM_PROTOCOL.   The  return
46       value  from proc is normally 0.  A non-zero return value indicates that
47       the event is not to be handled further; that is, proc has done all pro‐
48       cessing that is to be allowed for the event.
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50       If  there are multiple ClientMessage event handlers, each one is called
51       for each event, in the order in which they were established.
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53       Tk_DeleteClientMessageHandler may be called to delete a previously-cre‐
54       ated ClientMessage event handler: it deletes each handler it finds that
55       matches the proc argument.  If no such handler exists, then  Tk_Delete‐
56       ClientMessageHandler  returns without doing anything.  Although Tk sup‐
57       ports it, it's probably a bad idea to have more than one callback  with
58       the same proc argument.
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KEYWORDS

61       bind, callback, event, handler
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65Tk                                    8.4     Tk_CreateClientMessageHandler(3)
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