Set a string to a int: why it doesn't works?

[[!transform? &var=`[[+total]]`]]

$total = var_dump($var);
return $total;

string(18) "3"

$var = (int) $var;
$total = var_dump($var);
return $total;

int(0)

$var = $var+0;
$total = var_dump($var);
return $total;

int(0)

$var = $modx->getOption('var', $scriptProperties);

$var = $modx->getOption('var', $scriptProperties, 0);
return (int)$var;

$var = $modx->getOption('var', $scriptProperties, 0);
$total = (int)$var;

3

0

$nb = $modx->getOption('nb', $scriptProperties, 0);
$total = (int)$nb;

$nb = " 3.1416";
$total = (int)$nb;
echo $total;