function()
{
$this->imap = imap_check($this->stream);
if ($this->imap->Nmsgs > 0) {
$this->last_uid = $this->msguid($this->imap->Nmsgs);
$this->num_msg = $this->imap->Nmsgs;
}
else {
$this->last_uid = 0;
$this->num_msg = 0;
}
}