MAIL$_NORMAL       Normal successful completion.
    MAIL$_INVITMCOD    The specified item code is invalid.
    MAIL$_INVITMLEN    The specified item length is invalid.
    MAIL$_MISREQITEM   The required item is missing.
    MAIL$_NOFILEOPEN   No mail file is currently open.
    MAIL$_NOTISAM      The message file is not an indexed file.
    SS$_ACCVIO         Access violation.