usort question

[DjRubbish]

could someone tell me what $b is doing in this example from the manual about usort?

function cmp ($a, $b) {
if ($a == $b) return 0;
return ($a > $b) ? -1 : 1;
}

$a = array (3, 2, 5, 6, 1);

usort ($a, "cmp");

while (list ($key, $value) = each ($a)) {
echo "$key: $value\n";
}

I've only ever seen this explanation or very similar variants of it.

And I STILL don't get it.

Is $b just the other items in the array?

Like if $a was '2', $b would be 3,5,6 and 1 to be checked against $a?

Anyway, I hope someone can help.
Thanks.

[laserlight]

From what I see, both $a and $b are dummy variables.
They refer to some value in $a compared to another value in $b

[DjRubbish]

hey there,

thx for replying.

so you're saying usort passes values from the array into $a and $b and then compares $a and $b and sorts them.

If so, I think I get it!