Codeigniter Session Class userdata?

Question

i have some question in Codeigniter session class:

1. whats different between these

   $this->session->all_userdata(); 
   $this->session->userdata
   

   both of them return array of all user data in ci session (cooke).

2. and why this code is wrong:

   $this->session->userdata();
   

   but this one is correct:

   $this->session->userdata
   

   why?

Answer 1

for 1: $this->session->all_userdata(); is method to get CI-session's data $this->session->userdata is variable of CI-session's class, You shouldn't get session's data this way.

for 2: $this->session->userdata(); is correct because this way You'll use setters-getters mechanism (read more here), $this->session->userdata is incorrect because You try to get data directly (read link above to get more info)