If you compiled the example file first_module.c as a shared object, your result file should be first_module.so.
Depending on the build process you selected, you should either end up with a new PHP binary to be linked into your Web server (or run as CGI), or with an .so (shared object) file. If you compiled the example file first_module.c as a shared object, your result file should be first_module.so. To use it, you first have to copy it to a place from which it's accessible to PHP. For a simple test procedure, you can copy it to your htdocs directory and try it with the source in 예 29-1. If you compiled it into the PHP binary, omit the call to dl(), as the module's functionality is instantly available to your scripts.