From: php at lipfi dot ch Operating system: Gentoo Linux 2005.1 PHP version: 5.1.1 PHP Bug Type: Scripting Engine problem Bug description: Strange behaviour when multiplying floats with one multiplicator being 0
Description: ------------ When multiplying two float values, one being 0, one being negative, it's possible to either get 0 or -0 (!) as a result depending on the operands order. This is IMHO not how math is supposed to work. Additionally, I'm seing discrepancies between the variables value and what var_dump() things it contains. The problem is very simple to reproduce Reproduce code: --------------- <?php $v = 0*-0.02; var_dump($v); echo "$v\n"; $v = floatval($v); echo "$v\n\n"; $v = -0.02*0; var_dump($v); echo "$v\n"; ?> Expected result: ---------------- float(0) 0 0 float(0) 0 Actual result: -------------- float(0) -0 -0 float(0) 0 (the -0 obviously being the problem here) -- Edit bug report at http://bugs.php.net/?id=35656&edit=1 -- Try a CVS snapshot (PHP 4.4): http://bugs.php.net/fix.php?id=35656&r=trysnapshot44 Try a CVS snapshot (PHP 5.1): http://bugs.php.net/fix.php?id=35656&r=trysnapshot51 Try a CVS snapshot (PHP 6.0): http://bugs.php.net/fix.php?id=35656&r=trysnapshot60 Fixed in CVS: http://bugs.php.net/fix.php?id=35656&r=fixedcvs Fixed in release: http://bugs.php.net/fix.php?id=35656&r=alreadyfixed Need backtrace: http://bugs.php.net/fix.php?id=35656&r=needtrace Need Reproduce Script: http://bugs.php.net/fix.php?id=35656&r=needscript Try newer version: http://bugs.php.net/fix.php?id=35656&r=oldversion Not developer issue: http://bugs.php.net/fix.php?id=35656&r=support Expected behavior: http://bugs.php.net/fix.php?id=35656&r=notwrong Not enough info: http://bugs.php.net/fix.php?id=35656&r=notenoughinfo Submitted twice: http://bugs.php.net/fix.php?id=35656&r=submittedtwice register_globals: http://bugs.php.net/fix.php?id=35656&r=globals PHP 3 support discontinued: http://bugs.php.net/fix.php?id=35656&r=php3 Daylight Savings: http://bugs.php.net/fix.php?id=35656&r=dst IIS Stability: http://bugs.php.net/fix.php?id=35656&r=isapi Install GNU Sed: http://bugs.php.net/fix.php?id=35656&r=gnused Floating point limitations: http://bugs.php.net/fix.php?id=35656&r=float No Zend Extensions: http://bugs.php.net/fix.php?id=35656&r=nozend MySQL Configuration Error: http://bugs.php.net/fix.php?id=35656&r=mysqlcfg
