$_POST and $this->input->post()

[eluser]Kevin_3_57[/eluser]
Hi everybody, I was hoping if someone could enlight me a little.

When using one of the functions of codeigniter, the one to retrieve POST data, I came up with an error that $_POST doesn't make.

This right here, throws this: Fatal error: Can't use method return value in write context in about.php on line 717

Code:

if(isset($this->input->post("id_master"))) $data2["master"] = "1";

But, if I replace codeigniter's default function to retrieve post data, to $_POST:

Code:

if(isset($_POST['id_master'])) $data2["master"] = "1";

This works absolutely fine.

So, I really would like to stick to CodeIgniter helpers and functions... so why is this happening? What's wrong with this?

Thanks very much in advanced.
Kevin