Custom PHP extension: Invalid library (maybe not a PHP library)

Hi all! I'm interested in creating a custom PHP extension. I have found several so called tutorials, but the code examples they contain do not work for me. Let's stick to this site: http://devzone.zend.com/303/extension-writing-part-i-introduction-to-php-and-zend/ Basing on it I have following sources: ######################### config.m4: PHP_ARG_ENABLE(hello2,whether to enable hello2 support, [ --enable-hello2 Enable hello2 support]) if test "$PHP_HELLO2" = "yes"; then AC_DEFINE(HAVE_HELLO2,1,[Whether you want hello2 support]) PHP_NEW_EXTENSION(hello2, php_hello2.c, $ext_shared) fi ######################### ######################### php_hello2.h: #ifndef PHP_HELLO2_H #define PHP_HELLO2_H 1 #define PHP_HELLO_WORLD_VERSION "1.0" #define PHP_HELLO_WORLD_EXTNAME "hello2" PHP_FUNCTION(hello_world); extern zend_module_entry hello2_module_entry; #define phpext_hello2_ptr &hello2_module_entry #endif ######################### ######################### php_hello2.c: #ifdef HAVE_CONFIG_H #include "config.h" #endif #include "php.h" #include "php_hello2.h" static function_entry hello2_functions[] = { PHP_FE(hello_world, NULL) {NULL, NULL, NULL} }; zend_module_entry hello2_module_entry = { #if ZEND_MODULE_API_NO >= 20010901 STANDARD_MODULE_HEADER, #endif PHP_HELLO_WORLD_EXTNAME, hello2_functions, NULL, NULL, NULL, NULL, NULL, #if ZEND_MODULE_API_NO >= 20010901 PHP_HELLO_WORLD_VERSION, #endif STANDARD_MODULE_PROPERTIES }; #ifdef COMPILE_DL_HELLO2 ZEND_GET_MODULE(hello2) #endif PHP_FUNCTION(hello_world) { RETURN_STRING("Hello World", 1); } ######################### The code compiles well with these commands: $ ./configure --enable-hello2 $ make -j5 # make install But after I execute the command: $ php5 -d"extension=hello2.so" -v I get the following output. PHP Warning: PHP Startup: Invalid library (maybe not a PHP library) 'hello2.so' in Unknown on line 0 What I am missing here? Can someone help me? Thanks in advance. Kind Regards, Sławomir