phpClasses.org has a new book review this morning that everyone out there looking to PHP extionsions might be interested in.

This review of Building Custom PHP Extensions talks a little about the general state of PHP extentions then dives deeper and gets to the heart of the book - the actual development.

Blake Schwendiman, the author, wrote this book because he had the need to develop new functionality for his projects that was not available in PHP. Since he had to invest significantly on studying the subject, he felt that it would be a good idea to share the knowledge that he gained by writing this book.

The largest chapter of the book focus on the important details about how to do each thing that you may want to do in a normal PHP extension. It covers all the options of the ext_skel script, memory management functions, directory and file access functions, the PHP build system, how to declare functions that you extension makes available to PHP scripts, creating constants, accessing to your extension function arguments and their return values, manipulating variables, extension initialization and finally, how to provide new classes of objects via a new extension.

Sounds like this book would be a very productive purchase for anyone out there wanting to extend the way PHP works without diving headfirst into the core source...