(PHP 5 >= 5.6.0)
PDO::pgsqlGetNotify — Get asynchronous notification
$result_type = PDO::FETCH_USE_DEFAULT
   [, int $ms_timeout = 0
  ]] )Returns a result set representing a pending asynchronous notification.
result_type
       The format the result set should be returned as, represented as a
       PDO::FETCH_*
       constant.
      
ms_timeoutThe length of time to wait for a response, in milliseconds.
   If one or more notifications is pending, returns a single row, with fields
   message and pid, otherwise returns
   FALSE.