r &amp;serious
  error?)
</pre><p></p>
<p>This condition describes errors, typically caused by something that
has gone wrong in the interaction of the program with the external
world or the user.</p>
</dd>

</dl>
<h1>Examples</h1>
<pre>(define-condition-type &amp;c &amp;condition
  c?
  (x c-x))

(define-condition-type &amp;c1 &amp;c
  c1?
  (a c1-a))

(define-condition-type &amp;c2 &amp;c
  c2?
  (b c2-b))
(define v1 (make-condition &amp;c1 'x "V1" 'a "a1"))

(c? v1)        =&gt; #t
(c1? v1)       =&gt; #t