I'm new to PHP. Currently I'm learning on output buffering. Everyone says that there would an error if there is an output before header() function call. This is same with session() function. Currently I'm not getting this error (Cannot modify header information...) while practicing on localhost. I'm not sure what is problem. I've not changed my 'php.ini'. I'm using PHP 5.4.3 and Appache 2.2.22. I want to use buffer functions to buffer my output before I can send it to browser. For practice I want to see this error and then remove this error using output buffering.

Can anyone please let me know how I would get this header errors? The example that I've used is available in php.net. That is:
PHP Code:
/* This will give an error. Note the output
 * above, which is before the header() call */
header('Location: http://www.google.com/');