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Tk_SetClassProcs(3)	      Tk Library Procedures	     Tk_SetClassProcs(3)

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NAME
     Tk_SetClassProcs - register widget specific procedures

SYNOPSIS
     #include <tk.h>

     Tk_SetClassProcs(tkwin, procs, instanceData)

ARGUMENTS
     Tk_Window tkwin (in)		     Token for window to modify.

     const Tk_ClassProcs *procs (in)	     Pointer  to data structure contain-
					     ing  widget  specific   procedures.
					     The  data	structure  pointed to by
					     procs must be static:  Tk	keeps  a
					     reference to it as long as the win-
					     dow exists.

     ClientData instanceData (in)	     Arbitrary one-word value to pass to
					     widget callbacks.
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DESCRIPTION
     Tk_SetClassProcs is called to register a set of procedures that are used as
     callbacks in different places.

     The structure pointed to by procs contains the following:
	    typedef struct Tk_ClassProcs {
		unsigned int size;
		Tk_ClassWorldChangedProc *worldChangedProc;
		Tk_ClassCreateProc *createProc;
		Tk_ClassModalProc *modalProc;
	    } Tk_ClassProcs;
     The  size	field  is used to simplify future expansion of the structure. It
     should always be set to (literally) sizeof(Tk_ClassProcs).

     worldChangedProc is invoked when the system has altered in  some  way  that
     requires  some  reaction  from  the widget.  For example, when a font alias
     (see the font manual entry) is reconfigured, widgets configured to use that
     font alias must update their display accordingly.	worldChangedProc  should
     have arguments and results that match the type Tk_ClassWorldChangedProc:
	    typedef void Tk_ClassWorldChangedProc(
		    ClientData instanceData);
     The instanceData parameter passed to the worldChangedProc will be identical
     to the instanceData parameter passed to Tk_SetClassProcs.

     createProc  is used to create platform-dependent windows.	It is invoked by
     Tk_MakeWindowExist.  createProc should  have  arguments  and  results  that
     match the type Tk_ClassCreateProc:
	    typedef Window Tk_ClassCreateProc(
		    Tk_Window tkwin,
		    Window parent,
		    ClientData instanceData);
     The  tkwin  and  instanceData parameters will be identical to the tkwin and
     instanceData parameters passed to Tk_SetClassProcs.  The  parent  parameter
     will  be the parent of the window to be created.  The createProc should re-
     turn the created window.

     modalProc is invoked after all bindings on a widget have been triggered  in
     order  to handle a modal loop.  modalProc should have arguments and results
     that match the type Tk_ClassModalProc:
	    typedef void Tk_ClassModalProc(
		    Tk_Window tkwin,
		    XEvent *eventPtr);
     The tkwin parameter to modalProc will be identical to the	tkwin  parameter
     passed to Tk_SetClassProcs.  The eventPtr parameter will be a pointer to an
     XEvent structure describing the event being processed.

KEYWORDS
     callback, class

Tk				       8.4		     Tk_SetClassProcs(3)

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