title: Is php's socket_select() guaranteed to detect all client socket disconnections?
body: <p>Is php's <a href="http://php.net/manual/en/function.socket-select.php" rel="nofollow noreferrer">socket_select()</a> method guaranteed to detect all client socket disconnections?</p>
  
  <p>I've seen a few code examples that use the read array in php's socket_select() method to detect client socket disconnection, such as this one:
  <a href="https://stackoverflow.com/questions/3996215/how-to-detect-client-disconnection-on-php-socket-listener">How to detect client disconnection on PHP socket listener?</a></p>
  
  <p>But does it return FALSE for ALL client socket disconnection? If there are any exceptions, what are they?</p>