Starts a new transaction.

    Format

      SYS$START_TRANS  [efn] ,[flags] ,iosb [,[astadr] ,[astprm]

                       ,[tid] ,[timout] ,[acmode] ,[tx_class]]

    C Prototype

      int sys$start_trans  (unsigned int efn, unsigned int flags,

                           struct _iosb *iosb,...);