ctrstr

    OpenVMS usage char_string
    type          character-coded text string
    access        read only
    mechanism     by reference
    Address of a zero-terminated FAO control string.

 prmlst

    OpenVMS usage varying_arg
    type          quadword (signed or unsigned)
    access        read only
    mechanism     by value
    Optional FAO parameters. All arguments after the control string
    are copied into a quadword parameter list, as used by $FAOL_64.