测试代码：
$conn_string = "host=localhost port=5432 dbname=smnews user=postgres password=mt" ;
$dbconn = pg_connect($conn_string);
if (!$dbconn)
echo "连接失败！！！！！/r/n";
else
echo "连接成功！！！！！/r/n";
pg_close($dbconn);

thinkphp中提示：
Call to undefined function pg_connect()