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get_values_hook()					     get_values_hook()

  get_values_hook - Object class method for obtaining values of resources
  that do not appear in the resource list.

  typedef void (*XtArgsProc)(Widget, ArgList, Cardinal *);
	 Widget w;
	 ArgList args;
	 Cardinal *num_args;

  w	    Specifies the widget or object that is having  its	resources

  args	    Specifies the argument list that was passed to XtGetValues().

  num_args  Specifies the number of arguments in the argument list.

  The get_values_hook() method is registered on the get_values_hook field
  of the Object, RectObj, or Core class part structure, and is called  by
  XtGetValues()	 to  give  the widget a chance to supply the value of any
  resources that do not appear in the widget's resource list (by  calling
  XtGetSubvalues()  on	a  subpart,  for example) or to modify any of the
  returned values.

  The  get_values_hook()  method  is  chained  in  superclass-to-subclass
  order,   and	 cannot	 be  inherited.	  Classes  that	 do  not  need	a
  get_value_hook() method should  specify  NULL	 in  the  get_values_hook
  field of their class structure.

  See XtGetValues(1) for more information on when this method is invoked.

  If a widget or object has subparts with resources that do not appear in
  the resource list of	the  object  itself,  it  can  use  the	 get_val‐
  ues_hook()  method  to  call	XtGetSubvalues() passing a pointer to the
  subpart, the subpart resource list, and the args and num_args	 argument
  list.	 Using this technique, the application programmer will be able to
  query the value of subpart resources as  if  they  were  normal  widget

  Note	that  since  the Object class was added in Release 4, it is often
  easier to use objects rather than subparts, because  objects	get  more
  automatic  resource  handling	 by  the  Intrinsics than subparts do.	A
  get_values_hook() procedure is not limited to calling XtGetSubvalues();
  it  can call XtGetValues() on a widget or object, as shown in the exam‐
  ples below.  When using objects rather than subparts, it is also possi‐
  ble  to  give	 the  application programmer direct control over creating
  those objects.  If the  programmer  keeps  a	pointer	 to  the  created
  object,  then she can directly set and query the resource values of the
  object, and no get_values_hook() is necessary in the parent.

  The get_values_hook() method can also be used to  modify  the	 resource
  values  in args that would otherwise be returned to the user.	 A widget
  that displays a string, for example, might want to  return  a	 copy  of
  that string to the programmer rather than the string itself, so that if
  the programmer modifies the string, the widget will  not  be	affected.
  Widgets  that	 use  the  get_values_hook() method in this way should be
  sure to document which resources are copied in this  way  and	 must  be
  freed by the user.  (None of the Intrinsics widgets nor the Xaw widgets
  do this.)

  Note that the get_values_hook() method is not obsolete as are the other
  hook methods, initialize_hook() and set_values_hook().

  The  two  procedures below are the get_values_hook() methods of the Xaw
  Dialog and Xaw Text widget classes.  Note that both  use  XtGetValues()
  to obtain resources of a child widget or object, which they "export" as
  one of their own resources.

  The Dialog method checks the incoming	 argument  list	 for  a	 resource
  named	 XtNvalue,  and	 only queries the child for that single resource.
  The Text method simply passes the entire argument list in XtGetValues()
  calls	 to  two  different  child objects.  This method assumes that the
  Text widget and its two children objects do not have any  resources  by
  the  same name, so there is not potential for name conflicts.	 The Text
  widget controls the types of its subobjects, so this	is  a  reasonable
  assumption.	Since  all  objects  have an XtNdestroyCallback resource,
  however, if you were to query the value of this resource for	the  Text
  widget, you would get the callback list for one of its internal objects
  instead.  (This is not a practical problem because the callback list is
  in an internal compiled form and should not be queried anyway.)

     static void
     GetValuesHook(w, args, num_args)
     Widget w;
     ArgList args;
     Cardinal * num_args;
       Arg a[1];
       String s;
       DialogWidget src = (DialogWidget) w;
       register int i;

       for (i=0; i < *num_args; i++)
	 if (streq(args[i].name, XtNvalue)) {
	   XtSetArg(a[0], XtNstring, &s);
	   XtGetValues(src->dialog.valueW, a, 1);
	   *((char **) args[i].value) = s;

     static void
     GetValuesHook(w, args, num_args)
     Widget w;
     ArgList args;
     Cardinal * num_args;
       XtGetValues( ((TextWidget) w)->text.source, args, *num_args );
       XtGetValues( ((TextWidget) w)->text.sink, args, *num_args );

See Also
  XtGetSubvalues(1), XtGetValues(1),

Xt - Intrinsics Methods					     get_values_hook()

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