="spec value anchored" id="val-of_header"><a href="#val-of_header" class="anchor"></a><code><span><span class="keyword">val</span> of_header : <span>?warn_on_error:bool <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-t">t</a> <span class="arrow">&#45;&gt;</span></span> <span><a href="#type-t">t</a> option</span></span></code></div><div class="spec-doc"><p>Return approximate source file corresponding to the parameter if it's header file and file exists. returns None otherwise. WARNING: If wa