>R_OK</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">system_dir</span><span class="w"></span>
<span class="w">     </span><span class="k">implicit none</span>
<span class="k">     </span><span class="kt">character</span><span class="p">(</span><span class="nb">len</span><span cla