any function to check existing session variable?

[rolwong]

I'd like to know if there is any function to check what session variables I've defined . Thanks.

[drawmack]

just use a foreach to loop through the existing session variables.

[rolwong]

Sorry, let me clarify my question.
Let's say I have created a lot of session variables in many pages. Right now I would like to know what session variable names I have created. I'd like to know if I can use a function so that php can returned all the names of the sessioin variables I have defined.

[ahundiak]

Pretty much as drawmack said:
print_r(array_keys($_SESSION));