DEFINE_WIDGET_CLASS

     Defines a widget class for later use in creating widgets of that class
     using the Intrinsics or the Toolkit low-level creation routines.  Each
     call returns a different class integer.  You use the integer to specify
     the class of a widget when you create the widget.

     Syntax

     integer := DEFINE_WIDGET_CLASS (widget_class_name
                                     [, creation_routine_name
                                     [, creation_routine_image_name]])

  Parameters

     integer                        An integer used to identify the class of
                                    widget to be created by CREATE_WIDGET.

     widget_class_name              A string that is the name of the widget
                                    class record.  This is a universal
                                    symbol exported by the Toolkit or widget
                                    writer.

     creation_routine_name          A string that is the name of the
                                    low-level widget creation routine for
                                    this widget class.  The name can be
                                    either a VMS binding which is
                                    case-insensitive and contains a dollar
                                    sign, or a C binding which is
                                    case-sensitive and does not contain a
                                    dollar sign.

     creation_routine_image_name    A string that is the name of the
                                    shareable image in which the class
                                    record can be found.  Only the name of
                                    the file can be specified; device,
                                    directory, type, and version are not
                                    allowed.  If you do not specify an
                                    image, TPU assumes the widget is
                                    defined in DECW$XMLIBSHR.