First we create a function definition file: Then run the *ext_skel* script which creates all the required skeleton files. At this point you have a choice on how to proceed. You can either develop your extension under the main PHP framework where you run the top-level *buildconf* script to include your extension in PHP's main configuration script, or you can develop your extension in a completely separate directory where you run the *phpize* script to populate your extension directory with all the required files.