PHP 5.6.12 - Return of integer incorrect

Question

Previously I have been developing an app using PHP 5.6.7 in Linux, however recently I've switched to a Windows environment using WAMP 64 bit and upgraded PHP to 5.6.12 and been running into a few issues. One issue is in the backend PHP I have an array of integers. When I print to return to the front which prints the return array to the console I get a different format. That is:

$permission->fk_org_id = [24053826281537536,24051529749102626,111];
print json_encode($permission->fk_org_id);

Returns the following to the console:

0:24053826281538000
1:24051529749103000
2:111

Why is this happening?

Answer 1

Those numbers are too large to fit in a (32-bit) integer. They will be interpreted as a float, see the documentation:

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.

A float has a precision of about 14 significant digits, so that's why you see the zeroes.

Unfortunately, PHP on Windows does not support 64 bit integers, according to this answer:

On windows x86_64, PHP_INT_MAX is 2147483647. This is because in the underlying c-code, a long is 32 bit.

However, linux on x86_64 uses a 64bit long so PHP_INT_MAX is going to be 9223372036854775807.

Answer 2

You probably run your script on 32-bit machine where max int is 2147483647, so integer overflow occurres. According to documentation:

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);                     // int(2147483647)

$large_number = 2147483648;
var_dump($large_number);                     // float(2147483648)

$million = 1000000;
$large_number =  50000 * $million;
var_dump($large_number);                     // float(50000000000)
?>

More about integers you can find in documentation.