ctrstr

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

 buffer

    OpenVMS usage char_string
    type          character string
    access        write only
    mechanism     by reference
    Address of a string buffer into which to store the formatted
    string.

 buflen

    OpenVMS usage longword_unsigned
    type          longword (unsigned)
    access        read only
    mechanism     by value
    Maximum size of the string buffer.

 prmlst

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