title: error: expected unqualified-id before ‘__extension__’ in Linux (Cent OS)
body: <p>My code is below,</p>
  
  <pre><code>namespace A
  {
       namespace B
       {
             unsigned int htonl(unsigned int address)
             {
                  return 0;
             }
       }
  }
  </code></pre>
  
  <p>Now I know that <code>htonl</code> is a library function in Linux. Even though I am defining it under namespaces it produces the mentioned error. How can I fix it without changing the function signature? </p>