Session variables return completely after unsetting

I have a script th开发者_JAVA百科at should log the user out of the site. It unsets all $_SESSION and $_COOKIE variables related to the login data of the user. But somehow, it seems impossible to log out. I checked the $_SESSION array at the end of the logout script, and at the beginning of each page. At the end of the logout script it says 'array()', but when I click the home button - or any link on the site - the full session data is back again and I don't know where it comes from. This is how I try to unset the session data: unset($_SESSION); unset($_COOKIE["usid"]); unset($_COOKIE["pw"]); unset($_COOKIE["adm"]); -- I don't know how to put it on different lines, but it's not that hard to read.

Why do these data keep coming back?!

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The PHP documentation says "Do NOT unset the whole $_SESSION with unset($_SESSION) as this will disable the registering of session variables through the $_SESSION superglobal."

Try out this in stead: $_SESSION = array(); (as recommended on the PHP documentation).