how to check if a user logined?

[persiangulf]

I have a site that vbulletin is part of it. I want to use the vbulletin user table as my users table for both (my website and forum).
I have a problem to check if a user is logined or not ? though i saw the code and found out that i can use the global.php file and include it but it also includes other files that are in other folders and it makes problems.(my website file are in the outer folder of forum)
Is there a straightforward way to do this?

[Dismounted]

You must change the directory to the forum directory, using chdir(), before including global.php.

[persiangulf]

thanks that was great favor of you

--------------- Added [DATE]1240835192[/DATE] at [TIME]1240835192[/TIME] ---------------

by the way, i wanted to made logout link but i have problem in logouthash parameter that is made of two part that one of them is lastactivity and the other one is ... (i don't know please help me) . this is a sample of it :
login.php?do=logout& logouthash = 1240833757 - 81f79e1df06fb37cad64212a73ced51b0befd779 (what is this and where can i acquire it!)

[sanjeev_jha]

PHP Code:

logouthash= $vbulletin->userinfo['logouthash']; 


[Downsx]

nvm already said.