Function pickout

src/test/examples/testlo64.c:77–110

}

static void
pickout(PGconn *conn, Oid lobjId, pg_int64 start, int len)
{
	int			lobj_fd;
	char	   *buf;
	int			nbytes;
	int			nread;

	lobj_fd = lo_open(conn, lobjId, INV_READ);
	if (lobj_fd < 0)
		fprintf(stderr, "cannot open large object %u", lobjId);

	if (lo_lseek64(conn, lobj_fd, start, SEEK_SET) < 0)
		fprintf(stderr, "error in lo_lseek64: %s", PQerrorMessage(conn));

	if (lo_tell64(conn, lobj_fd) != start)
		fprintf(stderr, "error in lo_tell64: %s", PQerrorMessage(conn));

	buf = malloc(len + 1);

	nread = 0;
	while (len - nread > 0)
	{
		nbytes = lo_read(conn, lobj_fd, buf, len - nread);
		buf[nbytes] = '\0';
		fprintf(stderr, ">>> %s", buf);
		nread += nbytes;
		if (nbytes <= 0)
			break;				/* no more data? */
	}
	free(buf);
	fprintf(stderr, "\n");
	lo_close(conn, lobj_fd);
}

static void
overwrite(PGconn *conn, Oid lobjId, pg_int64 start, int len)