MAIL$_MAILFILE_DEFAULT_NAME
    MAIL$_MAILFILE_DEFAULT_NAME specifies the default file
    specification the Mail utility should use when opening a mail
    file. The buffer address field points to a character string 0 to
    255 characters long 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 buffer length field of the item
    descriptor, MAIL$MAILFILE_COMPRESS uses the current default
    directory as the default mail file specification.
    If you do not specify MAIL$_MAILFILE_DEFAULT_NAME, MAIL$MAILFILE_
    COMPRESS creates the default mail file specification from the
    following sources:
    o  Disk and directory defined in the caller's user authorization
       file (UAF)
    o  Subdirectory defined in the Mail user profile
    o  Default file type of .MAI
 MAIL$_MAILFILE_FULL_CLOSE
    The Boolean item code MAIL$_MAILFILE_FULL_CLOSE requests that
    the wastebasket folder be purged and that convert and reclaim
    operations be performed, if necessary.
    Specify the value 0 in the buffer length and buffer address
    fields of the item descriptor.
 MAIL$_MAILFILE_NAME
    MAIL$_MAILFILE_NAME specifies the name of a mail file to be
    opened. The buffer that the buffer address field points to
    contains a character string of 0 to 255 characters.
    Specify a value from 0 to 255 in the buffer length field of the
    item descriptor.
    If you do not specify MAIL$_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.