> ......... In my case, I used currval(). Basically:
>
> SELECT currval('table_field_seq');
>
> will return the most recently assigned value to the field *by the
> current
> backend* which means:
>
> - There's no danger of a race condition (another user creating a
> record in
> the time between your creating the record and calling currval); BUT
> - You must be using the same backend as you did on the creation.

This is the way I've used before. It seems the the better way
(thanks to Charles Martin <martin(at)chasm(dot)org>) is:

1) Do INSERT
PGresult* res = PQexec(conn, "INSERT......")

2) Get the OID of the just inserted record e.g
const char* oid = PQoidStatus(res)

3) Select the id of this record:
res = PQexec(conn, "SELECT id .... WHERE OID=....");