What is the purpose of the register function in PHP?

In PHP, the register function has been deprecated and is not recommended for use. Its purpose is to register variables in the global scope for global access. However, using it can decrease the readability and maintainability of code, as global variables are prone to unintended modifications by different parts of code. Instead, it is advisable to avoid using global variables as much as possible and manage data and state through passing parameters or using classes.