How to trigger integer overflow in PHP [duplicate] - php

Question

Ignoring the special libraries that allow you to work with very big numbers, what's the largest int value you can store in PHP?

Answer 1

From the PHP manual:
The size of an integer is
platform-dependent, although a maximum
value of about two billion is the
usual value (that's 32 bits signed).
PHP does not support unsigned
integers. Integer size can be
determined using the constant
PHP_INT_SIZE, and maximum value using
the constant PHP_INT_MAX since PHP
4.4.0 and PHP 5.0.5.
64-bit platforms usually have a maximum value of about 9E18, except on Windows prior to PHP 7, where it was always 32 bit.

Answer 2

32-bit builds of PHP:
Integers can be from -2,147,483,648 to 2,147,483,647 (~ ± 2 billion)
64-bit builds of PHP:
Integers can be from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (~ ± 9 quintillion)
Numbers are inclusive.
Note: some 64-bit builds once used 32-bit integers, particularly older Windows builds of PHP
Values outside of these ranges are represented by floating point values, as are non-integer values within these ranges. The interpreter will automatically determine when this switch to floating point needs to happen based on whether the result value of a calculation can't be represented as an integer.
PHP has no support for "unsigned" integers as such, limiting the maximum value of all integers to the range of a "signed" integer.

Answer 3

The size of PHP ints is platform dependent:
The size of an integer is
platform-dependent, although a maximum
value of about two billion is the
usual value (that's 32 bits signed).
PHP does not support unsigned
integers. Integer size can be
determined using the constant
PHP_INT_SIZE, and maximum value using
the constant PHP_INT_MAX since PHP
4.4.0 and PHP 5.0.5.
PHP 6 adds "longs" (64 bit ints).

Answer 4

(a little bit late, but could be useful)
Only trust PHP_INT_MAX and PHP_INT_SIZE, this value vary on your arch (32/64 bits) and your OS...
Any other "guess" or "hint" can be false.

Answer 5

Ah I found it: 232 - 1 (2147483647)
http://au2.php.net/int
Integer overflow
If PHP encounters a number beyond the bounds of the integer type, it will be interpreted as a float instead. Also, an operation which results in a number beyond the bounds of the integer type will return a float instead.
<?php
$large_number = 2147483647;
var_dump($large_number);
// output: int(2147483647)
$large_number = 2147483648;
var_dump($large_number);
// output: float(2147483648)

Answer 6

It depends on your OS, but 2147483647 is the usual value, according to the manual.

Answer 7

It subjects to architecture of the server on which PHP runs. For 64-bit,
print PHP_INT_MIN . ", ” . PHP_INT_MAX; yields -9223372036854775808, 9223372036854775807

Answer 8

Although PHP_INT_* constants exist for a very long time, the same MIN / MAX values could be found programmatically by left shifting until reaching the negative number:
$x = 1;
while ($x > 0 && $x <<= 1);
echo "MIN: ", $x;
echo PHP_EOL;
echo "MAX: ", ~$x;