n class="mdzsyn-keyword">:pack</span> <span class="mdzsyn-keyword">:int</span>)) <span class="mdzsyn-comment"># -&gt; 5</span></code></pre><p>C structs map to Janet tuples - that is, to pass a struct to an FFI function, pass in a tuple, and
struct-returning functions will return tuples. To
map C structs to other types (such as a Janet struct), you must do the conversion manually.
</p>
<h2 id="Array-Types">Array Types
</h2>
<p>Array types are defined with a Janet array of one or two elements - the first elem