WebReference.com has a new sample chapter from Sara Goleman's book "Extending and Embedding PHP" (Chapter 3) taking a look at memory management in PHP.

One of the most jarring differences between a managed language like PHP, and an unmanaged language like C is control over memory pointers.

The chapter looks at:

• Freeing up unneeded resources
• Handling error requests correctly
• An introduction to the Zend Memory Manager
• Counting references to avoid unnecessary copying
• The usefulness of "copy on write"
• Saving resources with "change on write"
• Difficulties with handling seperation of values

Each of the above items is accompanied by a good bit of text and code examples where appropriate (even a diagram or two to make things clearer).