CTFS_EVT
#define CT_ERESET CTFS_EVT(0) /* Reset event queue pointer */
#define CT_ERECV CTFS_EVT(1) /* Read next event */
#define CT_ECRECV CTFS_EVT(2) /* Read next critical event */
#define CT_ENEXT CTFS_EVT(3) /* Skip current event */
#define CT_ERELIABLE CTFS_EVT(4) /* Request reliable event receipt */