Seeking back to the beginning of a file on a PostgreSQL large object handle returns false, even though the seek succeeds.

The following script:

<?php
  $database = pg_connect ('dbname=pile_dev user=postgres');
  pg_exec ($database, 'begin transaction');
  $oid = pg_lo_create($database);
  $handle = pg_lo_open($database, $oid,  "rw");
  echo 'write: ';
  var_dump(pg_lo_write($handle, 'foo'));
  echo 'tell: ';
  var_dump(pg_lo_tell($handle));
  echo 'seek to begin: ';
  var_dump(pg_lo_seek($handle, 0, PGSQL_SEEK_SET));
  echo 'tell: ';
  var_dump(pg_lo_tell($handle));
  pg_exec($database,  'commit');
  pg_close($database);
?>

outputs:

  write: int(3)
  tell: int(3)
  seek to begin: bool(false)
  tell: int(0)


I expected:

  write: int(3)
  tell: int(3)
  seek to begin: bool(true)
  tell: int(0)