I'm in the middle of writing a plugin that needs to inlude admin.php. How can I retrieve the path for admin.php in the wp-admin directory? I mean not url but the installed directory path. I searched the forum and only could find the function, admin_url() http://codex.wordpress.org/Function_Reference/admin_url.
But this is not what I'm looking for since some users might be changing the file location for security and using redirects.
Thanks for your information.