s="special">)</span><span class="special">;</span>  <span class="comment">// works as expected</span>
        <span class="identifier">safe_f</span><span class="special">(</span><span class="number">100</span><span class="special">,</span> <span class="special">-</span><span class="number">100</span><span class="special">)</span><span class="special">;</span> <span class="comment">// throw error</span>
        <span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"e