ight"><pre><span></span><span class="w">     </span><span class="k">program </span><span class="n">demo_system_isreg</span><span class="w"></span>
<span class="w">     </span><span class="k">use </span><span class="n">M_system</span><span class="p">,</span><span class="w"> </span><span class="k">only</span><span class="w"> </span><span class="p">:</span><span class="w"> </span><span class="n">isreg</span><span class="o">=&gt;</span><span class="n">system_isreg</span><span class="p">,</span><span class="w"> 