apc_sma_info() always returns an empty array

Using APC as an app cache, however when running HHVM the apc_sma_info returns an empty array. If running via php-fpm (extension=apc.so) it returns the correct size array, is there some config that needs to be set to enable HHVM to talk to apc or is this a bug - have tried them all and so far no success. Regards.