Session idle time

[Anon]

Hi all,

I wonder if I can set the idle time limit in php.ini?
In my web site, I used apache + php4 + ssl_mod +informix as database. When user log on, a session will be created with his user id stored in the session variable. I need to set the idle time limit for the session so that user will be request for relogin for long idle time. Before every page is loaded, session variable is checked, if missing then login page is loaded instead. This make sure only proper logon user can view the pages. My problem is how to set idle time limit for the session? I tried session.cookie_lifetime session.gc_maxlifetime but not work.
Got any idea?

[rajtpd]

try your session.gc_probability setting under php.ini

[Anon]

Could you show me an example?
Let's say to set the idle limit to 30 min.
what value should the following properties set to?
cookie_lifetime, gc_maxlifetime and gc_probability.