In this second part of their "Writing PHP Extensions" series, Zend builds on part one and how to increase the power of your app, accepting parameters and how to manage them internally.

In Part One of this series you looked at the basic framework of a PHP extension. You declared simple functions that returned both static and dynamic values to the calling script, defined INI options, and declared internal values (globals). In this tutorial, you'll learn how to accept values passed into your functions from a calling script and discover how PHP and the Zend Engine manage variables internally.

They walk you through accepting input values to your extension, working with the zval ("the most difficult concepts you'll need to wrap your head around, they will also be the most vital"), creation of zvals, working with arrays, using symbol tables as arrays, counting references, and a little sanity checking.