This chapter discussed errors in PHP, including where they might arrive in your web applications, how PHP manages them, and how we can configure PHP's behavior in regard to these errors. We saw that we have a very high degree of control over them and can use this flexibility and configurability to write extremely robust web applications.
We were also introduced to exception handling in PHP5, which helps us generate more interesting and meaningful errors in your web applications. You can truly provide more information to the users and yourself by extending this system to include new errors of your generation.
The next chapter looks at cookies and sessions. Since HTTP is a stateless protocol that provides no means for tracking and managing users within your web application, these tools are used to get around this problem.