VMS Help MAIL Routines, MAIL$SEND_ADD_ADDRESS, Input Item Codes  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 MAIL$_SEND_USERNAME

    MAIL$_SEND_USERNAME specifies that the Mail utility add a
    specified user name to the address list. The buffer address
    field of the item descriptor points to a buffer that receives
    a character string 0 to 255 characters long.

    Specify a value from 0 to 255 in the buffer length field of the
    item descriptor.

    The item code MAIL$_SEND_USERNAME is required.

 MAIL$_SEND_USERNAME_TYPE

    MAIL$_SEND_USERNAME_TYPE specifies the type of user name added to
    the address list. The buffer address field of the item descriptor
    points to a word that contains the user name type.

    There are two types of user names, as follows:

    o  User name specified as a To: address (default)

    o  User name specified as a CC: address

                                   NOTE

       Currently, the symbols MAIL$_TO and MAIL$_CC define user
       name types.

 out_item_list

    OpenVMS usage:itmlst_3
    type:         longword
    access:       write only
    mechanism:    by reference
    Item list specifying the information you want the routine to
    return. The out_item_list argument is the address of a list of
    item descriptors, each of which describes an item of information.
    The list of item descriptors is terminated by longword value of
    0.