open_basedir question

Hello there, I have what should be a simple question: How can I get a script to fail (terminate or exit, whatever) on a failed open_basedir restriction? In other words, if I try to open a file outside of the open_basedir restriction, how do I get the script to stop? This should be simple and I must be missing something... Thanks in advance, -Dash As long as the answer is right, who cares if the question is wrong?