anchor.diff:  (defmacro define-server-type-callback
       (name (handle server-types error-code cookie) &body body)
     `(defcallback ,name slp-bool
  -       ((,handle slp-handle)
  -		(,server-types :string)
  -		(,error-code slp-error-type)
  -		(,cookie :pointer))
  +	 ((,handle slp-handle)
  +	  (,server-types :string)
  +	  (,error-code slp-error-type)
  +	  (,cookie :pointer))
        (declare (ignorable ,handle ,server-types ,error-code ,cookie))
        ,@body))
   
  
positive.code: (defmacro define-server-url-callback
      (name (handle url lifetime error-code cookie) &body body)
    `(defcallback ,name slp-bool
         ((,handle slp-handle)
  		(,url :string)
  		(,lifetime :unsigned-short)
  		(,error-code slp-error-type)
  		(,cookie :pointer))
       (declare (ignorable ,handle ,url ,lifetime ,error-code ,cookie))
       ,@body))
  
  
negative.code:   (if *slp-handle*
        (mem-ref *slp-handle* 'slp-handle)
        (error 'slp-error
  			 :code ""
  			 :message "SLP not opened, call SLP-OPEN first")))
  
  ;; slp free
  
  