On Alpha and Integrity server systems, allows a process to change
    the fault characteristic on a page or range of pages.

    Format

      SYS$SETFLT  inadr ,[retadr] ,[acmode] ,fault_flag

    C Prototype

      int sys$setflt  (struct _va_range *inadr, struct _va_range

                      *retadr, unsigned int acmode, unsigned int

                      fault_flag);