MAIL$_MAILFILE_DEFAULT_NAME

    MAIL$_MAILFILE_DEFAULT_NAME specifies the default file
    specification MAIL$MAILFILE_OPEN should use when opening a mail
    file. The buffer address field points to a character string of 0
    to 255 characters that defines the default file specification.

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

    If you specify the value 0 in the buffer length field of the item
    descriptor, MAIL$MAILFILE_OPEN uses the current default directory
    as the default mail file specification.

    If you do not specify MAIL$_MAILFILE_DEFAULT_NAME, MAIL$MAILFILE_
    OPEN creates the default mail file specification from the
    following sources:

    o  Disk and directory defined in the caller's user authorization
       file (UAF)

    o  Subdirectory defined in the Mail user profile

    o  Default file type of .MAI

 MAIL$_MAILFILE_NAME

    MAIL$_MAILFILE_NAME specifies the name of the mail file
    MAIL$MAILFILE_OPEN should open. The buffer address field
    points to a buffer that contains a character string of 0 to 255
    characters.

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

    If you do not MAIL$_MAILFILE_NAME, the default mail file name is
    MAIL.

 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.