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.

       Tk_ClassProcs *procs (in)	       Pointer	to data structure containing widget specific procedures.  The data structure pointed to by
					       procs must be static: Tk keeps a reference to it as long as the window 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.  world-
       ChangedProc 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-dependant 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 return 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)