APC Data Caching

I've got APC installed and caching op-code fine, and I'm preparing to use the data caching. I did a small test according to the manual:

PHP Code:

<?php$bar = 'BAR';apc_store('foo', $bar);var_dump(apc_fetch('foo'));?>

Returns:

string(3) "BAR"

All good. Then I run just the fetch bit:

PHP Code:

<?phpvar_dump(apc_fetch('foo'));?>

Returns:

bool(false)

It seems that the data is not caching beyond the execution of the file with apc_store in it. How to fix this? Or am I misunderstanding the way data caching works in APC? May be a silly question but I'm working with this for the first time and would appreciate help.