#46780 [Opn->Bgs]: Minus zero returned by simple multiplication of floating numbers

ID: 46780 Updated by: derick@php.net Reported By: preechaw at gmail dot com -Status: Open +Status: Bogus Bug Type: Math related Operating System: Windows XP PHP Version: 5.2.7 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://docs.sun.com/source/806-3568/ncg_goldberg.html Thank you for your interest in PHP. . Previous Comments: ------------------------------------------------------------------------ [2008-12-06 12:08:58] preechaw at gmail dot com Description: ------------ -0.1 * 0; // returns -0 I believe it should return 0 without the minus sign. -- I will also submit another bug for the "BC math related" type. echo bcadd("-0.0", "-0.0", 1); // returns -0.0 echo bccomp("-0.0", "0", 1); // returns -1 -- Reproduce code: --------------- <?php echo -0.1 * 0; // returns -0 ?> Expected result: ---------------- 0 Actual result: -------------- -0 ------------------------------------------------------------------------ -- Edit this bug report at http://bugs.php.net/?id=46780&edit=1