Edit report at https://bugs.php.net/bug.php?id=64459&edit=1
ID: 64459 Updated by: ahar...@php.net Reported by: marc-bennewitz at arcor dot de Summary: Wrong value on casting a float point number into int -Status: Open +Status: Not a bug Type: Bug Package: Scripting Engine problem Operating System: Linux acer-aspire-5680 3.2.0-38- PHP Version: master-Git-2013-03-19 (Git) Block user comment: N Private report: N New Comment: Floating point values have a limited precision. Hence a value might not have the same string representation after any processing. That also includes writing a floating point value in your script and directly printing it without any mathematical operations. If you would like to know more about "floats" and what IEEE 754 is, read this: http://www.floating-point-gui.de/ Thank you for your interest in PHP. Previous Comments: ------------------------------------------------------------------------ [2013-03-19 20:18:38] marc-bennewitz at arcor dot de Description: ------------ On some circumstances it's possible to get a wrong integer value on casting from float. I can reproduce this bug with the following installations: php -v PHP 5.3.10-1ubuntu3.6 with Suhosin-Patch (cli) (built: Mar 11 2013 14:34:31) Copyright (c) 1997-2012 The PHP Group Zend Engine v2.3.0, Copyright (c) 1998-2012 Zend Technologies with Xdebug v2.1.0, Copyright (c) 2002-2010, by Derick Rethans ./sapi/cli/php -v PHP 5.6.0-dev (cli) (built: Mar 17 2013 22:02:54) Copyright (c) 1997-2013 The PHP Group Zend Engine v2.6.0-dev, Copyright (c) 1998-2013 Zend Technologies Test script: --------------- // this works $v = (float) 6; var_dump($v, (int)$v); // this is wrong $v = log(64, 2); var_dump($v, (int)$v); Expected result: ---------------- float(6) int(6) float(6) int(6) Actual result: -------------- float(6) int(6) float(6) int(5) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=64459&edit=1
