used in the model block or user-defined probability functions.</p>
<p>See the <a href="#function-bodies.section">section on function bodies</a> for more information on these special types of function.</p>
</section>
</section>
<section id="argument-types-and-qualifiers" class="level2">
<h2 class="anchored" data-anchor-id="argument-types-and-qualifiers">Argument types and qualifiers</h2>
<p>Stan’s functions all have declared types for both arguments and returned value. As with built-in functions, user-defi