(PHP 4, PHP 5)
pg_port — Return the port number associated with the connection
$connection
  ] )
   pg_port() returns the port number that the
   given PostgreSQL connection resource is
   connected to.
  
connection
       PostgreSQL database connection resource.  When 
       connection is not present, the default connection 
       is used. The default connection is the last connection made by 
       pg_connect() or pg_pconnect().
      
   An int containing the port number of the database
   server the connection is to, 
   or FALSE on error.
  
Example #1 pg_port() example
<?php
$pgsql_conn = pg_connect("dbname=mark host=localhost");
if ($pgsql_conn) {
   print "Successfully connected to port: " . pg_port($pgsql_conn) . "<br/>\n";
} else {
   print pg_last_error($pgsql_conn);
   exit;
}
?>