SS$_NORMAL         Normal successful completion.
    MAIL$_INVITMCOD    The specified item code is invalid.
    MAIL$_INVITMLEN    The specified item length is invalid.
    MAIL$_MISREQITEM   The required item is missing.
    MAIL$_NOSUCHUSR    The specified user name is not valid.
    MAIL$_NOSYSPRV     The operation requires the SYSPRV privilege.
    SS$_ACCVIO         Access violation.