我应该如何包含文档根目录之外的文件？

Question

I wanted to include pear/Mail.php.
I asked the hosting support to provide me the path, It is "/usr/local/php-5.3.17/share/pear/". But it doesn't work independently or from document root, and it seems I can't access upper level directories by using "../".

There are two parent folder for the document root: /home/www/

Answer 1

include '/usr/local/php-5.3.17/share/pear/Mail.php';