title: How to access FDs in fd_set through indexing in Linux?
body: <p>For example, I can access them with <code>fd_set.fd_array[i]</code> in Windows..</p>
  
  <pre><code>request_list getIncomingRequests()
  {
      fd_set master_set_copy = master_set;
      request_list requests;
      int socket_count = select(0, &amp;master_set_copy, nullptr, nullptr, nullptr);
      for (int i = 0; i &lt; socket_count; ++i)
      {
      #ifdef _WIN32
          auto req_fd = master_set_copy.fd_array[i];
      #else
          auto req_fd = master_set_copy...[i]; // ??
      #endif
          sockaddr_in req_addr;
          getsockname(req_fd, (sockaddr*)&amp;req_addr, &amp;addr_len);
          requests.push_back(request(req_fd, this-&gt;fd, req_addr));
      }
      return requests;
  }
  </code></pre>
  
  <p>But <code>fd_array</code> doesn't exist in Linux so I need an equivalent.</p>