<a name="math_toolkit.fp_facets.reference.signed_zero"></a></span><a class="link" href="reference.html#math_toolkit.fp_facets.reference.signed_zero">signed_zero</a>
      </h6>
<p>
        If the <code class="computeroutput"><span class="identifier">signed_zero</span></code> flag is
        used with <code class="computeroutput"><span class="identifier">nonfinite_num_put</span></code>,
        then the facet will always distinguish between positive and negative zero.
        It will format positive zero as 