Is there public API to fetch errcode?

[Sergey Fukanchik]

Hi Postgres hackers,
ereport() can accept an error code. For example:
            ereport(FATAL,
                    (errcode(ERRCODE_TOO_MANY_CONNECTIONS),
                     errmsg("number of requested standby connections 
exceeds \"max_wal_senders\" (currently %d)",
                            max_wal_senders)));
In this case the error happens during connection initialization, outside 
of an SQL query. I.e. PGresult is not available.

I suspect that the error code is available on the client as 
PGconn->last_sqlstate however it is private and I can't find any public 
API to fetch it.

Does libpq have an API to extract this code?

---

Sergey