Ends a transaction by attempting to commit it, and returns the
    outcome of the transaction.

    Format

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

                     ,[tid]]

    C Prototype

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

                         struct _iosb *iosb,...);