title: Is there any case where the C static keyword should or could be used in header files for variables?
body: <p><a href="https://stackoverflow.com/questions/1433204/how-do-i-use-extern-to-share-variables-between-source-files/1433387#1433387">We can assume</a> that the <code>static</code> keyword shall not be used in a header file <em>- for variables</em>.</p>
  
  <blockquote>
    <p>A header file only contains <code>extern</code> declarations of variables — never <code>static</code> or unqualified variable definitions.</p>
  </blockquote>
  
  <p>Is there any exception where the C <code>static</code> keyword should or could be used in header files for variables? Why?</p>