Tk_SetClassProcs(3tk)

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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 con-
                                               taining widget specific  proce-
                                               dures.    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 iden-
       tical to the instanceData paramter 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  cre-
       ateProc 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 parame-
       ter 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)