using session vars with PHP

Hi
I am doing some php stuff which will need session vars to be set to remain active during the whole session across all pages in the application. Question:
Do I have to put session_start(); on every page that will need to set, read or create session vars?
Also is it best to use session_register(); or $_SESSION[]?
I have started by using $_SESSION, as I am told this is better?
What then is the method for reading or changing these vars once created?
Sorry, a lot of questions!
Thanks, any help appreciated!

fox66,

You must always perform a call to session_start() at the beginning of every page where you need to access the session variables. Otherwise, you won't be able to use them!

As for the session_register vs $_SESSION, use the $_SESSION autoglobal. It gives you greater functionality than session_register.

When you want to work with the variables, simply modify, add, read or delete them within the $_SESSION array. Manipulate the array just like you would any other.

-Jeb.

Personally fox, I agree with Jeb.. adding or removing items from the $_SESSION array is much easier than registering or unregistering session variables... I'm lazy.. so it works for me

many thanks, $_SESSION it is!
Cheers