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

 MAIL$_MESSAGE_BACK

    When you specify the Boolean item code MAIL$_MESSAGE_BACK,
    MAIL$MESSAGE_MODIFY reads the identification number of the
    specified message in order to return the first record in the
    preceding message.

    Specify the value 0 in the buffer length and buffer address
    fields of the item descriptor.

    Do not specify the item codes MAIL$_MESSAGE_BACK, MAIL$_MESSAGE_
    ID, and MAIL$_MESSAGE_NEXT in the same call to MAIL$MESSAGE_
    MODIFY.

 MAIL$_MESSAGE_FLAGS

    MAIL$_MESSAGE_FLAGS specifies system flags for new mail. The
    buffer address field of the item descriptor points to a word that
    contains bit mask offsets. The following offsets can be used to
    modify the 2-byte bit mask:

    o  MAIL$V_replied

    o  MAIL$V_marked

 MAIL$_MESSAGE_ID

    MAIL$_MESSAGE_ID specifies the message identification number of
    the message on which an operation is to be performed. The buffer
    address field of the item descriptor points to a longword that
    contains the message identification number.

    Do not specify the item codes MAIL$_MESSAGE_BACK, MAIL$_MESSAGE_
    ID, and MAIL$_MESSAGE_NEXT in the same call to MAIL$MESSAGE_
    MODIFY.

 MAIL$_MESSAGE_NEXT

    When you specify the Boolean item code MAIL$_MESSAGE_NEXT,
    MAIL$MESSAGE_MODIFY reads the message identification number of
    a message and returns the first record in the message following
    the current message.

    Specify the value 0 in the buffer length and buffer address
    fields of the item descriptor.

    Do not specify the item codes MAIL$_MESSAGE_BACK, MAIL$_MESSAGE_
    ID, and MAIL$_MESSAGE_NEXT in the same call to MAIL$MESSAGE_
    MODIFY.

 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.