VMS Help RTL Routines, LIB$, LIB$SCOPY_R_DX_64, Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 quad-integer-source-length

    OpenVMS usage:quadword_unsigned
    type:         quadword (unsigned)
    access:       read only
    mechanism:    by reference

    Length of the source string in bytes. The quad-integer-source-
    length argument is the address of an unsigned quadword that
    contains the length of the source string.

 source-string

    OpenVMS usage:char_string
    type:         character string
    access:       read only
    mechanism:    by reference

    Source string to be copied to the destination string by
    LIB$SCOPY_R_DX_64. The source-string argument is the address
    of this source string.

 destination-string

    OpenVMS usage:char_string
    type:         character string
    access:       write only
    mechanism:    by descriptor

    Destination string to which the source string is copied. The
    destination-string argument contains the address of a descriptor
    pointing to this destination string.