<?php
error_reporting('E_ALL');

$pgcon = pg_codnnect('host=127.0.0.1 port=5432 dbname=postgis user=postegres password=xxxx');

$stat = pg_connection_status($pgcon);
if ($stat === PGSQL_CONNECTION_OK) {
  echo 'Verbindungsstatus ok';
} else {
  echo 'Verbindungsstatus bad';
}