Unveiling the Distinctive Roles of session_unset() and session_destroy() in PHP

In the realm of PHP session management, two critical functions emerge: session_unset() and session_destroy(). While they both appear to revolve around session data manipulation, their functions and effects differ significantly.

1. Understanding the Difference

As per the PHP documentation, session_destroy() ruthlessly annihilates all data associated with the current session, leaving no remnants behind. Alternatively, session_unset() exhibits a subtler approach, merely clearing the $_SESSION variable, the local manifestation of session data. It is akin to performing $_SESSION = array();.

2. Destroying the Session Entity

Neither session_unset() nor session_destroy() directly eradicates the session itself. To achieve this, one must employ the potent session_regenerate_id() function. This invocation creates a fresh session ID and simultaneously invalidates the preceding session, effectively terminating its existence.

3. Preserving the Session Cookie

A crucial distinction between session_unset() and session_destroy() lies in their treatment of session cookies. Both functions abstain from meddling with the session cookie at the client's end. This ensures that the user remains authenticated and can seamlessly continue their session in the event of potential server-side adjustments.