Changes the base priority of the process. The base priority is
    used to determine the order in which executable processes are to
    run.

    Format

      SYS$SETPRI  [pidadr] ,[prcnam] ,pri ,[prvpri] ,[nullarg]

                  ,[nullarg]

    C Prototype

      int sys$setpri  (unsigned int *pidadr, void *prcnam, unsigned

                      int pri, unsigned int *prvpri, unsigned int

                      *pol, unsigned int *prvpol);