In this chapter you looked at the internal representation of PHP variables. You learned to distinguish types, set and retrieve values, and add variables into symbol tables and fetch them back out. In the next chapter you'll build on this knowledge by learning how to make copies of a zval, how to destroy them when they're no longer needed, and most importantly, how to avoid making copies when you don't need to.
You'll also take a look at Zend's per-request memory management layer, and examine persistent versus non-persistent allocations. By the end of the next chapter you'll have the solid foundation necessary to begin creating a working extension and experimenting with your own code variations.
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