php图片上传报错error=3

/**

• Created by PhpStorm.
• User: rosen
• Date: 15-11-5
• Time: 下午8:43*/print_r($_FILES['file']);

?>

为什么程序运行结果报错Array ( [name] => 2015-10-19 18:47:42屏幕截图.png [type] => [tmp_name] => [error] => 3 [size] => 0 )