Why is it necessary to call session_start() at a specific point when storing objects in the $_SESSION variable?

When storing objects in the $_SESSION variable in PHP, it is necessary to call session_start() before attempting to access or modify the $_SESSION variable. This is because session_start() initializes a session or resumes the current one, allowing the script to interact with the session data. Without calling session_start(), the session data will not be available, leading to errors when trying to store or retrieve objects from the $_SESSION variable. 

<?php
session_start();

// Store object in $_SESSION variable
$_SESSION['myObject'] = new MyClass();

Keywords

session_start $_SESSION variable objects serialization session management

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