WITH A COUPLE OF "SNEAK PREVIEW" EXCEPTIONS, the extension functions you've dealt with so far have been simple, return-only factories. Most functions, however, won't be so single purposed. You usually want to pass in some kind of parameter and receive a meaningful response based on the value and some additional processing.
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