if($parent) { build_thread_cache($parent); }
	else # must find out what our new thread number is
	{
		if($filename)
		{
			$sth=$dbh->prepare("SELECT num FROM ".SQL_TABLE." WHERE image=?;") or make_error(S_SQLFAIL);
			$sth->execute($filename) or make_error(S_SQLFAIL);
		}
		else
		{
			$sth=$dbh->prepare("SELECT num FROM ".SQL_TABLE." WHERE timestamp=? AND comment=?;") or make_error(S_SQLFAIL);
			$sth->execute($time,$comment) or make_error(S_SQLFAIL);
		}
		my $num=($sth->fetchrow_array())[0];

		if($num)
		{
			build_thread_cache($num);
		}
	}

is what I used as a base for it. I'm not very good at Perl, so I'm just happy it works.