PHP4 questions

I've noticed a few changes in php4 from php3 that I didn't see documented anywhere, as well as some interesting improvements. One thing that's bugging me is that the mail() function appears to now escape things like single quotes and double quotes in the headers and body of messages. I don't recall seeing this in php3 - am I correct in this? Is there a way to stop it? setcookie() now appears to return 1 on success, whereas before it returned a 0. The parser previously on occasion didn't catch an extra '}', so on the switch to php4, a coworker's script broke. :) In one script of mine, I had a function with a global variable which I then foolishly unset. In php3, the variable was not totally destroyed; its scope remained global even within the function, which allowed it to be assigned a value in the global scope. In php4, the unset works correctly. Did anyone else notice this behavior? Hopefully you didn't, since it was a mistake on my part. :) Thanks, Blaise