2. EL 9
  3. tk-devel
  4. Tk_CreateClientMessageHandler(3)

Scroll to navigation

Tk_CreateClientMessageHandler(3) Tk Library Procedures Tk_CreateClientMessageHandler(3) 





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.
    
    

    

  








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







  

    8.4
    Tk