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.

There is a native class called OverflowException, which is emitted when a number gets too large, and may be caught.

<?php

    $a = PHP_INT_MAX;
    $b = (int) ($a +  1);

    echo $a.PHP_EOL;
    echo $b;

?>