How to get the list of apache modules enabled with php

I have tried this

<?php

print_r(apache_get_modules());

?>

and got this

Fatal error:  Call to undefined function apache_ge开发者_运维问答t_modules() in

Why the error for built in function and how to get list of modules

The manual page contains details about the PHP and Apache version that support apache_get_modules().

You must be running PHP >= 4.3.2 and using Apache 2 handler API, or PHP >= 5.0 and Apache 1 or Apache 2 filter API.