Edit report at https://bugs.php.net/bug.php?id=62729&edit=1
ID: 62729
Updated by: ras...@php.net
Reported by: arnaud at wixiweb dot fr
Summary: fmod() and "modulo" operator do not work are not
consistent with big int.
-Status: Open
+Status: Analyzed
Type: Bug
Package: Scripting Engine problem
Operating System: Linux / Windows
PHP Version: 5.4.5
Block user comment: N
Private report: N
New Comment:
Note that longs on 64-bit Windows are still only 32 bits. A long on 64-bit
Linux
is 64 bits. So, to work with large values like that you will need to use
something like bcmod()
fmod(x,y) returns x - n * y where n is the quotient of x / y floor'ed and
converted to an integer which isn't always going to give you the same result as
x % y. If you are working with integers use %. If you are working with doubles,
use fmod(). And keep in mind that these are signed so you don't have the whole
32/64 bit space. The upper bit is the sign.
Given this I am not sure I see a bug here. You are mostly comparing 32-bit to
64-bit here.
Previous Comments:
------------------------------------------------------------------------
[2012-08-03 00:15:33] arnaud at wixiweb dot fr
Description:
------------
fmod() and "modulo" operator do not work are not consistent with big int.
Moreover, the results change between windows(PHP5.4) to linux(PHP5.3)
See the test script for more informations
Test script:
---------------
// On Windows64 with PHP 5.4
// Example 1
var_dump(fmod(12345678901234567, 62)); // float(52)
var_dump(12345678901234567 % 62); // int(20)
// Example 2
var_dump(fmod(9999999999999999111, 62)); // float(18)
var_dump(9999999999999999111 % 62); // int(0)
// On Linux64 with PHP 5.3
// Example 3
var_dump(fmod(12345678901234567, 62)); // float(52)
var_dump(12345678901234567 % 62); // int(51)
// Example 4
var_dump(fmod(9999999999999999111, 62)); // float(18)
var_dump(9999999999999999111 % 62); // int(-60)
------------------------------------------------------------------------
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Edit this bug report at https://bugs.php.net/bug.php?id=62729&edit=1
