session - php session_start with include files

Question

i learned a lot about session start from my previous question. Now i'm wondering how session locking occurs when files are included in other files. Lets say i have:

page.php

include('header.php');
...some html content....
include('sub_page.php');
...more html....

header.php:

session_start();
..save session vars...
..print web page header...

sub_page.php

session_start();
...use session vars....
..print page content...

When i open page.php, does the session become unlocked as soon as header.php is done? or is it live for the whole page.php life, so sub_page's session is blocked? Is the session_start in sub_page necessary? Would it be better practice if I session_write_close every time i'm done with session data? (Though that would mean session_starting everytime i'd like to use a session variable).

Answer 1

I would recommend creating a session.php file that you would include once, at the first line of each page. That way, the session is handled in ONE file, in case you need to change validation or session settings (and don't need to worry about your question).