(PHP 4 >= 4.3.0, PHP 5)
pg_get_notify — Gets SQL NOTIFY message
$connection
   [, int $result_type
  ] )pg_get_notify() gets notifications generated by a NOTIFY SQL command. To receive notifications, the LISTEN SQL command must be issued.
connectionPostgreSQL database connection resource.
result_type
       An optional parameter that controls
       how the returned array is indexed.
       result_type is a constant and can take the
       following values: PGSQL_ASSOC, 
       PGSQL_NUM and PGSQL_BOTH.
       Using PGSQL_NUM, pg_get_notify()
       will return an array with numerical indices, using
       PGSQL_ASSOC it will return only associative indices
       while PGSQL_BOTH, the default, will return both
       numerical and associative indices.
      
   An array containing the NOTIFY message name and backend PID.
   Otherwise if no NOTIFY is waiting, then FALSE is returned.
  
Example #1 PostgreSQL NOTIFY message
<?php 
$conn = pg_pconnect("dbname=publisher");
if (!$conn) {
  echo "An error occurred.\n";
  exit;
}
// Listen 'author_updated' message from other processes
pg_query($conn, 'LISTEN author_updated;');
$notify = pg_get_notify($conn);
if (!$notify) {
  echo "No messages\n";
} else {
  print_r($notify);
}
?>