librenms-librenms/includes/polling/mempools/fortigate.inc.php

<?php

// Simple hard-coded poller for Fortinet Fortigate
// Yes, it really can be this simple.
echo 'Fortigate MemPool';

$mempool['perc'] = snmp_get($device, 'FORTINET-FORTIGATE-MIB::fgSysMemUsage.0', '-OvQ');
$mempool['total'] = snmp_get($device, 'FORTINET-FORTIGATE-MIB::fgSysMemCapacity.0', '-OvQ');
$mempool['used'] = ($mempool['total'] * ($mempool['perc'] / 100));
$mempool['free'] = ($mempool['total'] - $mempool['used']);

echo '(U: ' . $mempool['used'] . ' T: ' . $mempool['total'] . ' F: ' . $mempool['free'] . ') ';