ci框架上传文件问题

PHP code

 function do_upload() {  $config['upload_path'] = base_url().'img/';  $config['allowed_types'] = 'gif|jpg|png';  $config['max_size'] = '100';  $config['max_width']  = '1024';  $config['max_height']  = '768';    $this->load->library('upload', $config);   if ( ! $this->upload->do_upload())  {   $error = array('error' => $this->upload->display_errors());      $this->load->view('admin/upload_form', $error);  }   else  {   $data = array('upload_data' => $this->upload->data());     print_r($data);  }

我这么写，总是提示说上传路径不正确.

[解决办法]
上传路径设置是否正确呢？
[解决办法]
$config['upload_path'] = base_url().'img/';

手动写个路径测测。