Tk_SetClassProcs(3)

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 pro-
                                             cedures.   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.   worldChangedProc  should
     have   arguments   and   results   that   match   the   type

Tk                      Last change: 8.4                        1

Tk_SetClassProcs(3)   Tk Library Procedures   Tk_SetClassProcs(3)

     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  describ-
     ing the event being processed.

KEYWORDS

     callback, class

Tk                      Last change: 8.4                        2