cf_id

    OpenVMS usage:identifier
    type:         longword integer (unsigned)
    access:       read only
    mechanism:    by reference
    Address of a longword that NCS uses to identify a conversion
    function. The cf_id argument is required and can be obtained by a
    call to the NCS$GET_CF routine.

    All calls to the NCS$CONVERT routine and the call to the NCS$END_
    CF routine that terminates the conversion must pass this longword
    identifier. Upon completion, the NCS$END_CF routine releases the
    memory used to store the conversion function and sets the value
    of the longword identifier to 0.

 source

    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by descriptor
    Descriptor of source string.

 dest

    OpenVMS usage:char_string
    type:         character string
    access:       write only
    mechanism:    by descriptor
    Descriptor of destination string.

 ret_length

    OpenVMS usage:word unsigned
    type:         word (unsigned)
    access:       write only
    mechanism:    by reference
    Length of converted string.

 not_cvt

    OpenVMS usage:word unsigned
    type:         word (unsigned)
    access:       write only
    mechanism:    by reference
    Number of characters in the source string that were not fully
    converted.