Ignoring the special libraries that allow you to work with very numbers, what's the largest int you can store in PHP?
A:
Ah I found it: 232 - 1 (2147483647)
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)
nickf
2009-03-22 07:36:16
This is what it would be on a 32-bit platform. Consider also that many people run servers on a 64-bit platform.
thomasrutter
2010-05-16 03:44:24
+1
A:
The size of PHP ints is platform independent:
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).
cletus
2009-03-22 07:36:21
i don't get these downvotes.. this is a perfectly good answer, even with some extra information thrown in. +1 to correct it.
nickf
2009-03-22 08:08:30
+1
A:
It depends on your OS, but 2147483647 is the usual value, according to the manual.
Bryson
2009-03-22 07:36:50
Specifically, it depends on whether you are running on a 32-bit platform or 64-bit. 32-bit is only "usual" in a world where most people run 32-bit servers. Increasingly this is becoming not the case.
thomasrutter
2010-05-16 03:47:23
+6
A:
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.
karim79
2009-03-22 07:36:51
Well, on amd64 linux, which is quite common nowadays, its 9223372036854775807 (2^63-1)
derobert
2009-03-22 07:51:06
That's a lot of digits - there's the first reason I can think of to ever choose AMD over Intel when shopping for a dedicated server. :)
karim79
2009-03-22 08:02:55
@karim79, I think it's due to the arch being 64-bit, not it being AMD. =]
strager
2009-03-22 08:23:41
@karim79, AMD64 is one name of the 64-bit architecture used by both AMD and Intel these days. Other names for it include x64 and Intel 64. As strager says, nothing to do with it being AMD
thomasrutter
2010-05-16 03:42:00
A:
32-bit builds of PHP:
- Integers can be from -2147483648 to 2147483647
64-bit builds of PHP:
- Integers can be from -9223372036854775808 to 9223372036854775807
Numbers are inclusive.
Values outside of these ranges are usually represented by floating point values, as are non-integer values within these ranges.
There are exceptions. For example, on a 32-bit build the crc32() function wraps resulting values above 2147483647 to become negative integers, which can be a gotcha when trying to create portable code as a 64-bit build returns them as positive integers.
PHP has no support for "unsigned" integers as such.
thomasrutter
2010-05-16 04:01:56