ctrstr

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

 prmlst

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