(Alpha and I64 only.) The Invoke $FAOL_64 System Service to
    Format Output routine calls the $FAOL_64 system service,
    returning the string in the semantics you provide. If called with
    other than a fixed-length string for output, the length of the
    resultant string is limited to 256 bytes and truncation occurs.

    Format

      LIB$SYS_FAOL_64  character-string [,resultant-length]

                       ,resultant-string ,directive-argument-address