Example

The following procedure is a sample ProcessOnItemHelp() function that would be invoked by choosing On Item from the Help menu.

void  ProcessOnItemHelp(
   Widget widget)
 {
  /* Declare a variable for the selected widget. */ 
  Widget selWidget=NULL;
   int status=DtHELP_SELECT_ERROR;
  /* Get an application shell widget from our widget hierarchy to
        * pass into DtHelpReturnSelectedWidgetId().
    */
  while (!XtIsSubclass(widget, applicationShellWidgetClass))
                    widget = XtParent(widget);
  status = DtHelpReturnSelectedWidgetId(widget, NULL, &selWidget);
  switch ((int)status)
     {
       case DtHELP_SELECT_ERROR:
         printf("Selection Error, cannot continue\n");
      break;
      case DtHELP_SELECT_VALID:
          /* We have a valid widget selection, now let's look for 
                   * a registered help callback to invoke.
           */
         while (selWidget != NULL)
           {
             if ((XtHasCallbacks(selWidget, XmNhelpCallback)
                                      == XtCallbackHasSome))
               {
                 /* Found a help callback, so just call it */
                XtCallCallbacks((Widget)selWidget,
                                 XmNhelpCallback,NULL);
                 break;
               }
            else
              /* No help callback on current widget, 
                          * so try the widget's parent
               */
                 selWidget = XtParent(selWidget);
           }
      break;
       case DtHELP_SELECT_ABORT:
         printf("Selection Aborted by user.\n");
      break;
      case DtHELP_SELECT_INVALID:
         printf("You must select a component within your app.\n");
      break;
     }
 }