PQoidValue have no use?

I posted this to pgsql-generl(at)postgresql(dot)org
yesterday, and wait someone can enlighten me.

1.
The oid may overlap; Insert may fail if i create a
primary key on the oid column(Thank Richard Huxton and
Michael Glaesemann). So I can't locate the single
record I Insert by the oid obtained from PQoidValue.
Then, PQoidValue have no use?

2.
I can use currtid2 to get the ctid after Delete. But
in this method the speed is slow down by the extra sql
query(SELECT currtid2('a'::text,...). I am very
pleasure if the ctid is not changed after Delete or a
function such as 'PQctidValue' can be found in
libpq.:)

3.
How to get ctid after Insert?

I want my code can deal with any table, so I can't add
addtional primary key on tables.

Sincerely,
Songsubo

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