By now you've gotten your hands a little dirty with real, functional code that can communicate with userspace through simple input/output functions. You've explored the zval reference counting system a little more deeply and learned ways to control how and when variables will be passed to your internal function.
In the next chapter you'll explore the array data type and see how its userspace representation maps to its underlying HashTable. You'll also take a look at the wide selection of Zend and PHP API functions available for manipulating these complex structures.
The PHP Life Cycle
Variables from the Inside Out
Setting Up a Build Environment
Your First Extension
Working with Arrays and HashTables
The Resource Data Type
Startup, Shutdown, and a Few Points in Between
Diverting the Stream
Configuration and Linking
Setting Up a Host Environment
Appendix A. A Zend API Reference
Appendix B. PHPAPI
Appendix C. Extending and Embedding Cookbook
Appendix D. Additional Resources