Fix a bug in the C interface.
Fix a bug in the C interface.

flashxio/FlashX,zheng-da/FlashX,silky/FlashGraph,icoming/FlashGraph,zheng-da/FlashX,icoming/FlashX,icoming/FlashX,zheng-da/FlashX,icoming/FlashGraph,flashxio/FlashX,icoming/FlashGraph,zheng-da/FlashX,icoming/FlashGraph,icoming/FlashX,silky/FlashGraph,flashxio/FlashX,silky/FlashGraph,flashxio/FlashX,silky/FlashGraph,flashxio/FlashX,icoming/FlashGraph,icoming/FlashX,zheng-da/FlashX,silky/FlashGraph,flashxio/FlashX,icoming/FlashX