Difference between safe mode on and off?

What things are different when safe_mode is on?

[dbzfyam]

I've written a simple poll script for a friend. It worked perfectly on my server (with safe_mode off) but when I tried it on his server (safe_mode on), it didn't work anyore. I wasn't able to write to files and couldn't log in (white screen).

Can anyone tell me what the differences are with safe_mode on? What kind of things do I have to change (I suspect the $_POST variables etc work differently)?

I searched this site aswell as on Google but only got unrelated pages, so sorry if his has been asked for a million times already.

Thanks in advance,
Stefan

Edit: At least, I think it has to do with safe_mode. I read somewhere it could have to do with register_globals aswell

[eelixduppy]

Have you checked out the documentation on this: Safe Mode [us2.php.net]. More specifically the Functions restricted/disabled by safe mode [us2.php.net].

Hope this helps!

[dbzfyam]

Thanks! Made a few changes an it seems to be working now. Much appreciated!