Data Conversion

Summary

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.