<?php
$capacities = array(25,150,50000,200000,5000000);
foreach ($capacities as $c) {
echo sprintf("Capacity of %s will be allowed to overdraw by %s.\n", $c, log($c,1));
}

Capacity of 25 will be allowed to overdraw by NAN.
Capacity of 150 will be allowed to overdraw by NAN.
Capacity of 50000 will be allowed to overdraw by NAN.
Capacity of 200000 will be allowed to overdraw by NAN.
Capacity of 5000000 will be allowed to overdraw by NAN.

Output for 4.3.0 - 5.3.3, hhvm-3.10.0 - 3.12.0

Capacity of 25 will be allowed to overdraw by INF.
Capacity of 150 will be allowed to overdraw by INF.
Capacity of 50000 will be allowed to overdraw by INF.
Capacity of 200000 will be allowed to overdraw by INF.
Capacity of 5000000 will be allowed to overdraw by INF.