title: What address clause for a GNAT.Sockets.Selector_Type
body: <p>I'm using a <code>Selector_Type</code> in my code.</p>
  
  <p>On one hand, the <code>Selector_Type</code> from <code>GNAT.Sockets</code> <a href="http://gnuada.sourceforge.net/source-gcc-4.2.2/g-socket__ads.html" rel="nofollow noreferrer">comes with</a>  the pragma:</p>
  
  <pre><code>pragma Volatile (Selector_Type);
  </code></pre>
  
  <p>On the other hand, Gnatckeck's <a href="http://docs.adacore.com/live/wave/asis/html/gnatcheck_rm/gnatcheck_rm/predefined_rules.html#volatile-objects-without-address-clauses" rel="nofollow noreferrer">rule 9.1.1.2</a> applied to my code will raise</p>
  
  <blockquote>
    <p>volatile object with no address clause [Volatile_Objects_Without_Address_Clauses]</p>
  </blockquote>
  
  <p>because of the pragma.</p>
  
  <p>This topic isn't handled in <a href="https://en.wikibooks.org/wiki/Ada_Programming/Libraries/GNAT.Sockets_examples" rel="nofollow noreferrer">wikibook's example</a> nor do I address this issue anywhere in my base code.</p>
  
  <p>So, what address should I use for my selector?</p>