cache_expire VS gc_maxlifetime (php.ini)

What is the difference?

[tata668]

What is the difference between "session.cache_expire" and "session.gc_maxlifetime" in php.ini? I think I once knew that but I'm not sure anymore! ;-)

And looking at the PHP manual doesn't help me!

I know what session.gc_maxlifetime does: it tells the garbage collector which sessions are old enough to be deleted.

But I don't understand session.cache_expire! What does "Document expires after n minutes" means?
Which document?

Thanks for your help!

[jatar_k]

[php.net...]

session.gc_maxlifetime specifies the number of seconds after which data will be seen as 'garbage' and cleaned up.

session.cache_expire specifies time-to-live for cached session pages in minutes, this has no effect for nocache limiter. Defaults to 180.