echo vs echo intval PHP

Question

Please can some one explain the result differences below

echo intval(1e10); 

Output 1410065408

Answer 1

A signed integer has a maximum value. On 32-bit systems, that's 2^16 or 2147483647. When intval-ing a number that's larger, it will overflow. The value you found can also calculated:

php > echo 1e10 % (2147483647);
1410065408

Answer 2

From PHP Manual:

The maximum value depends on the system. 32 bit systems have a maximum signed integer range of -2147483648 to 2147483647. So for example on such a system, intval('1000000000000') will return 2147483647. The maximum signed integer value for 64 bit systems is 9223372036854775807.

intval will truncate the number

Answer 3

Code:

<?php

echo 'intval: ' . intval( 1e10 ) . PHP_EOL;
echo '1e10: ' . 1e10 . PHP_EOL;

Runs from cli

Output:

intval: 10000000000
1e10: 10000000000

Ubuntu 12.10 x64 php5.4

In other words, you are using a x86 (32bit) machine.