Inactivity Logout

I have browsed this forum on how to implement a inactivity logout (session timeout) and I tried the following but I never get a timeout to occur:
In the after login event:

ini_set("session.gc_maxlifetime","30");
In the php.ini:

session.save_path = "\XAMPP\tmp"

; After this number of seconds, stored data will be seen as 'garbage' and

; cleaned up by the garbage collection process.

; http://php.net/session.gc-maxlifetime

session.gc_maxlifetime = 30
I am using XAMMP.
Do you all know what I am doing wrong?
Thanks in advance.