tifier">string_type</span> <a name="id-1_3_47_5_18_2_1_1_3_7-bb"></a><span class="identifier">fold_case</span><span class="special">(</span><span class="identifier">char_type</span> ch<span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>
<p>Returns a <code class="computeroutput">string_type</code> containing all the characters that compare equal disregrarding case to the one passed in. This function can only be called if <code class="computeroutput"><code clas