Unlink question more or less

I want to use unlink() to delete a wildcard, but at the moment I keep getting parse errors. Here's what happening: I'm mucking around with some login stuff, when a user logs in it writes a flat file that collects some information about them, the flat file is created with the name username.dateyeartime Now each time they log in I want to delete that file and replace it with the new file that has the latest dateyeartime ending on it. I've tried unlink (username.*); but that returns an error. Is there a way for unlink() to recongize wildcards? If not how would I do this?