macroexpansion of a function using this type would
look like:

<pre class="lisp">  CFFI&gt; <span class="paren1">(<span class="lisp-bg">macroexpand-1 '<span class="paren2">(<span class="lisp-bg"><i><span class="symbol">defcfun</span></i> bar my-boolean <span class="paren3">(<span class="lisp-bg">x my-boolean</span>)</span></span>)</span></span>)</span>
  <span class="comment">;; (simplified, downcased, etc...)
  </span><span class="paren1">(<span class="lisp-bg"><i><span class="symbol">defun</span></i> bar 