;;;; descriptions of DEFSTRUCTs which are to be handled before any others

;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.

(;; Define the STRUCTURE-OBJECT class as a subclass of
 ;; INSTANCE. This has to be handled early because the design of the
 ;; DEFSTRUCT system, dating back to pre-1999 CMU CL, requires that
 ;; STRUCTURE-OBJECT be the first DEFSTRUCT executed.
 ((structure-object (:alternate-metaclass sb!kernel:instance)
		    (:copier nil))
  ;; (There are no slots.)
  )

 ;; The target ALIEN-VALUE class must be defined early in the cross-compiler
 ;; build sequence in order to set up superclass relationships involving it.
 ;;
 ;; FIXME: Since this definition refers to SB!ALIEN:ALIEN-TYPE, which is also
 ;; defined as a structure, perhaps it might be reasonable to add an entry,
 ;; somewhere before this definition, to define SB!ALIEN:ALIEN-TYPE? That
 ;; way, any tests for SB!ALIEN:ALIEN-TYPE in the slot accessor functions
 ;; could be implemented more efficiently.
 ((sb!alien-internals:alien-value)
  (sap (required-argument) :type sb!sys:system-area-pointer)
  (type (required-argument) :type sb!alien::alien-type)))