Function lo_truncate64

src/interfaces/libpq/fe-lobj.c:196–237

* lo_truncate64 * truncates an existing large object to the given size * * returns 0 upon success * returns -1 upon failure */

 * returns -1 upon failure
 */
int
lo_truncate64(PGconn *conn, int fd, pg_int64 len)
{
	PQArgBlock	argv[2];
	PGresult   *res;
	int			retval;
	int			result_len;

	if (lo_initialize(conn) < 0)
		return -1;

	if (conn->lobjfuncs->fn_lo_truncate64 == 0)
	{
		appendPQExpBuffer(&conn->errorMessage,
						  libpq_gettext("cannot determine OID of function %s\n"),
						  "lo_truncate64");
		return -1;
	}

	argv[0].isint = 1;
	argv[0].len = 4;
	argv[0].u.integer = fd;

	len = lo_hton64(len);
	argv[1].isint = 0;
	argv[1].len = 8;
	argv[1].u.ptr = (int *) &len;

	res = PQfn(conn, conn->lobjfuncs->fn_lo_truncate64,
			   &retval, &result_len, 1, argv, 2);

	if (PQresultStatus(res) == PGRES_COMMAND_OK)
	{
		PQclear(res);
		return retval;
	}
	else
	{
		PQclear(res);
		return -1;
	}
}

/*
 * lo_read