$facebook->get_loggedin_user(); is Undefined?

This question was asked before, but it wasn't answered properly. Can someone please explain how to fix this problem? Right now I am just including facebook.php file from the PHP SDK. And the following code is giving me the error:

$facebook->get_loggedin_user();

Fatal error: Call to undefined method Facebook::get_loggedin_user() 

Any idea what to do?

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So I was just informed that the old API is not going to work anymore. If anyo开发者_开发百科ne has a link to a good tutorial to use the new (Graph?) API, please share. Thanks in advance! :)

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I think you're using documentation from the old api with the new SDK, which does not have that method and follows a completely different flow.

Check usage here: https://github.com/facebook/php-sdk/

Either way if you want serious help you should provide more info (SDK version, contextual code).