</span><span class=machine><span class=font-tt>is(</span></span><span class=font-it>discr</span><span class=machine><span class=font-tt>)</span></span>, where <span class=font-it>discr</span> is a C l-value
built from other parameters of the current function, or other fields
of the current <span class=machine><span class=font-tt>struct</span></span>. Both the discriminant and the
case labels must be of an integer type. Unless a <span class=machine><span class=font-tt>default</span></span> case is
given, the