Overflow¶

Overflow happens when a value goes beyond a limit : out of its range of existence, the behavior of the value is now unknown.

Overflow happens with integers (limited to PHP_INT_MAX and PHP_INT_MIN), floats (PHP_FLOAT_MAX and PHP_FLOAT_MIN).

Other situations, such as accessing an array element or a string character beyond its last element, defaults to returning null.

<?php
$a = PHP_INT_MAX;
$b = (int) ($a +  1);

echo $a.PHP_EOL;
echo $b;

?>