Calling lo_open within user defined C function - Mailing list pgsql-hackers

From Vincent Roberts
Subject Calling lo_open within user defined C function
Date
Msg-id 3B2528F6.5D1D474@emanon.net
Whole thread Raw
Responses Re: Calling lo_open within user defined C function  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
I am trying to create a user defined C function that will
be called within  PL/pgSQL

Namely, I need a function that will create a new Large Object and copy
the data
of an existing Large Object into the new Large Object.

This is the way the function would be registered

CREATE FUNCTION copyoid(oid) RETURNS oid  AS '/copyoid.so'  LANGUAGE
'C';

I notice that the lo_create and lo_open functions require a postgres
connection (PGConn)

Oid lo_creat(PGconn *conn, int mode)
int lo_open(PGconn *conn, Oid lobjId, int mode)

Since the function I wish to create will be executed within the backend,

how do I handle
the conn (PGconn) variable?

I realize I will need to open the original large object , create a new
large object and then
read the old and write the new until done, and then close both.

Every example I can find opens a connection and then uses the new
connection for these functions.

Is this required or can I use the "current" connection ?

Thanks



pgsql-hackers by date:

Previous
From: Darren Johnson
Date:
Subject: Postgres Replication
Next
From: Jan Wieck
Date:
Subject: Re: Re: REPLACE INTO table a la mySQL