codeigniter session to third party site

[eluser]xeroblast[/eluser]
i have a main site (codeigniter), when a user logs-in to the main site, he/she is automatically logs-in to the phpbb and wordpress because i will remove the login page of phpbb and wordpress.

1. when user register to codeigniter, he/she is also be automatically register to phpbb & wordpress.
2. when user logs-in to codeigniter, he/she is also automatically login to phpbb and wordpress.
3. when user logs-out to codeigniter, he/she is also be automatically logout to phpbb and wordpress.

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can you explain what youre doing in the code you provided? i couldnt get what the code means to my problem.

thanks.