Bug #50630 [Opn->Bgs]: Modulo on strings/floats won't work on huge numbers

Edit report at http://bugs.php.net/bug.php?id=50630&edit=1 ID: 50630 Updated by: tony2001@php.net Reported by: bananen-joe at bananen-joe dot de Summary: Modulo on strings/floats won't work on huge numbers -Status: Open +Status: Bogus Type: Bug Package: Scripting Engine problem Operating System: win32 only - Windows XP SP3 PHP Version: 5.3.1 New Comment: Sorry, but your problem does not imply a bug in PHP itself. For a list of more appropriate places to ask for help using PHP, please visit http://www.php.net/support.php as this bug system is not the appropriate forum for asking support questions. Due to the volume of reports we can not explain in detail here why your report is not a bug. The support channels will be able to provide an explanation for you. Thank you for your interest in PHP. Previous Comments: ------------------------------------------------------------------------ [2010-01-06 06:46:18] federico dot lebron at gmail dot com The size of 9999999990 is larger than PHP_INT_MAX, so when converting to integer (since you asked for modulo, and it gets converted to integer), you're getting undefined behavior, as per http://php.net/manual/en/language.types.integer.php . No warnings or notices will be triggered in such a case. Internally (and on this machine, with PHP compiled as 32 bit), strtol("9999999990", NULL, 10) is being called for the string case, which is 2147483647. This is noted in the intval function's documentation, so it's expected. For the float case, (long) (unsigned long) (long long int) 9999999990 is being casted, which is 1410065398, but this is undefined behavior. ------------------------------------------------------------------------ [2010-01-01 22:25:24] bananen-joe at bananen-joe dot de Description: ------------ If you use the modulo operator on huge numbers (which cannot be converted into integers) you get a strange result. Even not error is reported. Reproduce code: --------------- error_reporting(E_ALL); $number = '9999999990'; echo "$number % 10 = ", $number % 10, "<br>"; $number = 9999999990; echo "$number % 10 = ", $number % 10, "<br>"; $number = '99990'; echo "$number % 10 = ", $number % 10, "<br>"; $number = (float) 99990; echo "$number % 10 = ", $number % 10, "<br>"; Expected result: ---------------- 9999999990 % 10 = 0 (or even an error notice/warning) 9999999990 % 10 = 0 (or even an error notice/warning) 99990 % 10 = 0 99990 % 10 = 0 Actual result: -------------- 9999999990 % 10 = 7 9999999990 % 10 = 8 99990 % 10 = 0 99990 % 10 = 0 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/bug.php?id=50630&edit=1