(PHP 5 >= 5.6.0)
pg_connect_poll — Poll the status of an in-progress asynchronous PostgreSQL connection attempt.
$connection
  ] )
   pg_connect_poll() polls the status of a PostgreSQL
   connection created by calling pg_connect() with the
   PGSQL_CONNECT_ASYNC option.
  
connectionPostgreSQL database connection resource.
   Returns PGSQL_POLLING_FAILED,
   PGSQL_POLLING_READING,
   PGSQL_POLLING_WRITING,
   PGSQL_POLLING_OK, or
   PGSQL_POLLING_ACTIVE.