TkSetClassProcs(3) Tk Library Procedures TkSetClassProcs(3)

NAME
       TkSetClassProcs - register widget specific procedures

SYNOPSIS
       ##iinncclluuddee <>

       TTkkSSeettCCllaassssPPrrooccss(tkwin, procs, instanceData)

AARRGGUUMMEENNTTSS
       TkWindow      tkwin          (in)      Token for window to modify.

       TkClassProcs  *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.



DESCRIPTION
       TTkkSSeettCCllaassssPPrrooccss 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 TkClassProcs {
                unsigned int size;
                TkClassWorldChangedProc *worldChangedProc;
                TkClassCreateProc *createProc;
                TkClassModalProc *modalProc;
              } TkClassProcs;
       The  size  field is used to simplify future expansion of the structure.
       It should always be set to (literally) ssiizzeeooff((TTkkCCllaassssPPrrooccss)).

       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 ffoonntt 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
       TTkkCCllaassssWWoorrllddCChhaannggeeddPPrroocc:
              typedef void TkClassWorldChangedProc(
                ClientData instanceData);
       The instanceData parameter passed to the worldChangedProc will be iden-
       tical to the instanceData paramter passed to TTkkSSeettCCllaassssPPrrooccss.

       createProc is used to create platform-dependant windows.  It is invoked
       by  TTkkMMaakkeeWWiinnddoowwEExxiisstt.   createProc  should have arguments and results
       that match the type TTkkCCllaassssCCrreeaatteePPrroocc:
              typedef Window TkClassCreateProc(
                TkWindow tkwin,
                Window parent,
                ClientData instanceData);
       The tkwin and instanceData parameters will be identical  to  the  tkwin
       and  instanceData  parameters  passed  to TTkkSSeettCCllaassssPPrrooccss.  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 TTkkCCllaassssMMooddaallPPrroocc:
              typedef void TkClassModalProc(
                TkWindow tkwin,
                XEvent *eventPtr);
       The tkwin parameter to modalProc will be identical to the tkwin parame-
       ter passed to TTkkSSeettCCllaassssPPrrooccss.   The  eventPtr  parameter  will  be  a
       pointer to an XEvent structure describing the event being processed.


KKEEYYWWOORRDDSS
       callback, class



Tk                                    8.4                  TkSetClassProcs(3)