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.
_________________________________________________________________

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-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