[Risk] was php configured with --enable-memory-limit?

or, question in another way: is memory_get_usage() available so we can watch our memory?

If the server you are developing on has it enabled you would be able to see if your script was running over. I would guess it is enabled as they have put a limit on memory usage in the rules and this seems the most likely way to monitor it.

only xs0 or matt can answer with certainty.

This is just my guess your mileage may vary,
B

Only xs0 can answer this as he will be running the scripts. He is on vacation, but will be back soon.

I would guess he will have it enabled...

Well, as the rules say, PHP will be compiled with default options, i.e.

configure --with-apache=...

and that's it. So, you can't use memory_get_usage().

(I have other ways of limiting memory usage )

my development area has register globals on, and I want to make sure I don't mess up, I need to specifically do a get to retrieve the variables i.e.

$start = $_GET['start'];

Yup, that's right.