Dbms_output.put_line does not write to stdout

Question

I expect the following code to fail and to write 'ERRORE' to stdout:
------------------- mm.sql
set serveroutput on
BEGIN
select 1/0 from dual;
exception
when others then
dbms_output.put_line('ERRORE');
END;
I execute this from the command line
sqlplus rmsas_test/rmsas_test < mm.sql > mm.log 2>&1
It produces
---------------------------- mm.log
SQL*Plus: Release 9.2.0.6.0 - Production on Gio Lug 13 16:42:27 2006
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.6.0 - 64bit Production
JServer Release 9.2.0.6.0 - Production
SQL> SQL> 2 3 4 5 6 7 Disconnected from Oracle9i Enterprise Edition Release 9.2.0.6.0 - 64bit Production
JServer Release 9.2.0.6.0 - Production
But no 'ERRORE' has been written to stdout????
Why?
Thanks
Mauro

Answer 1

Just a comment. There are no STDOUT or STDERR devices when dealing with PL/SQL programs.
The code runs inside an Oracle server process. That process itself is detached from any display device, any input device (e.g. mouse or keyboard) and any peripheral device (e.g. printer).
DBMS_OUTPUT is simply a persistant PL/SQL buffer that can be created in an Oracle session. The contents of this buffer can be displayed by a client (using the DBMS_OUTPUT API to read and clear the buffer). Do not confuse it with a proper STDOUT/STDERR device.