(PHP 4, PHP 5, PHP 7, PHP 8)
session_unset — Free all session variables
The session_unset() function frees all session variables currently registered.
This function has no parameters.
| Version | Description | 
|---|---|
| 7.2.0 | The return type of this function is bool now. Formerly, it has been void. | 
Note:
If $_SESSION is used, use unset() to unregister a session variable, i.e.
unset($_SESSION['varname']);.
    Do NOT unset the whole $_SESSION with
    unset($_SESSION) as this will disable the registering
    of session variables through the $_SESSION superglobal.
   
Note:
The use of session_unset() is identical to
$_SESSION = [].
    This function works only if a session is active. It will not clear the
    $_SESSION array if the session has not been started yet
    or has already been destroyed. Use $_SESSION = [] to unset all
    session variables even if the session is not active.