Re: Retrieving multiple error messages via libpq

Jeffrey Brendecke <yakhki(at)yahoo(dot)de> writes:
> When I submit the following SQL statement for execution via the psql client:

> 'BEGIN TRANSACTION; INSERT INTO IdOnly (id) VALUES (40); INSERT INTO IdOnly (id) VALUES (21); INSERT INTO IdOnly (id) VALUES (42); COMMIT TRANSACTION;'

> I get the following error messages (this failure is expected):

> ERROR: duplicate key violates unique constraint "idonly_pkey"
> ERROR: current transaction is aborted, commands ignored until end of transaction block

> However, when retreiving the error message via PQresultErrorMessage(), I get:
> ERROR: duplicate key violates unique constraint "idonly_pkey"

> How is the additional error message retrieved?

It isn't, because there isn't any additional message. When you submit
multiple commands in a single PQexec string (as I suspect you did),
the backend abandons processing the string as soon as there's one error.
psql, however, chops up its input at semicolons and submits each command
as a separate PQexec.

regards, tom lane