I'm not sure if you can tell this from google maps etc, but if you are going to visit the Cregagh library from the Knock Dual Carriageway (A55) end of the Cregagh Road, it is quite well hidden from the main road.
In case this helps - approx 200 yards from the Carriageway - on the right hand side ...look out for a row of shops (bakery,newsagents,chemist etc)and a pelican/pedestrian crossing....Turn left immediately (and slowly) at this crossing and hopefully you'll be able to drive in to the library grounds and park.