title: Is it necessary to reset the fd_set between select system call?
body: <p>I am facing a problem using the select function in Unix. </p>
  
  <p>I have a server that waits for for a connection. First I add the listening socket file descriptor <code>listener</code> to the fd_set <code>readfds</code> using <code>FD_SET(listener, readfds)</code> and then I use that in <code>select()</code>. </p>
  
  <p>When I get a connection, I call <code>accept()</code> and set the <code>readfds</code> in select with the accepted file descriptor and start receiving the data from connection. However, when I check the code in strace, The select doesn't show the listener in the <code>readfds</code> while <code>select()</code> is executing a second time. </p>
  
  <p>Do I need to set the listener file descriptor again using <code>FD_SET(listener, readfds)</code> before calling <code>select()</code> again?</p>
  
  <p>Thanks.</p>