You encountered several newyet familiarconcepts through the course of this chapter including the internal notion of a thread-safe global variable, and how to expose userspace utilities such as constants, pre-initialized variables, and superglobal variables. In the next chapter, you'll discover how to declare and resolve php.ini values and even tie them to the internal thread-safe global structures you just set up.
The PHP Life Cycle
Variables from the Inside Out
Memory Management
Setting Up a Build Environment
Your First Extension
Returning Values
Accepting Parameters
Working with Arrays and HashTables
The Resource Data Type
PHP4 Objects
PHP5 Objects
Startup, Shutdown, and a Few Points in Between
INI Settings
Accessing Streams
Implementing Streams
Diverting the Stream
Configuration and Linking
Extension Generators
Setting Up a Host Environment
Advanced Embedding
Appendix A. A Zend API Reference
Appendix B. PHPAPI
Appendix C. Extending and Embedding Cookbook
Appendix D. Additional Resources