如何在我的网站上阅读wordpress cookies ?

I want to integrate my website with wordpress.I want to know as to how can i read wordpress cookies so that i dont need to authenticate users again in my website.I tried including the header file of wordpress in my website, but then i was unable to connect to the database of my website.Both of which are different.Can i set additional parameters of cookies like user level,etc?My website is written in php.I want to integrate my website with wordpress.I