strange thing-interactional of two different database connection

Database

strange thing-interactional of two different database connection

I found a strange phenomenon happened in NCR-CLI.

I want to use two different database connection in one process.
according to the CLISAMP.c, I think that DBCAREA will keep all connection info.
so I defined two DBACAREA, one is dbc_a, dbc_b. corspondingly, I copy the codes(initial, connect, disconnect, etc)
to make sure that two connection is irrelative.

the test code is very simple. following is pseudocode:

DBCAREA dbc_a
DBCAREA dbc_b

dbc_a.connect
dbc_b.connect

dbc_a.disconnect
dbc_b.disconnect --------there is a error when running here."disconnect failed -- CLI : 304 Message Not Found!"

If so, I can not use multi database connection to imporve the performance.

Hope some one can tell the reason and how to deal with it.
Thanks a lot.