fills it with n elements.
The elements are copied into the array via <code class="mendoza-code">memcpy</code>.
</p>
<pre class="mendoza-codeblock"><code data-language="c"><span class="mdzsyn-identifier">JANET_API</span> <span class="mdzsyn-type">void</span> <span class="mdzsyn-identifier">janet_array_ensure</span><span class="mdzsyn-operator">(</span><span class="mdzsyn-identifier">JanetArray</span> <span class="mdzsyn-operator">*</span><span class="mdzsyn-identifier">array</span><span class="mdzsyn-operato