Bug #61624 [Opn->Nab]: round

Edit report at https://bugs.php.net/bug.php?id=61624&edit=1 ID: 61624 Updated by: aharvey@php.net Reported by: gufophp at gmail dot com Summary: round -Status: Open +Status: Not a bug Type: Bug Package: Math related Operating System: win32 PHP Version: 5.4.0 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. The return value of round() is still a floating point number. If the precision is high enough, printing that float may result in seeing additional significant digits because of the imprecision inherent to floating point arithmetic. Previous Comments: ------------------------------------------------------------------------ [2012-04-05 13:08:07] gufophp at gmail dot com php.ini change precision to precision = 17 ------------------------------------------------------------------------ [2012-04-05 03:05:37] reeze dot xia at gmail dot com Hi, gufophp: I can't reproduce it in both 5.4 & 5.3 | Win7 & Mac OS X. can you feedback more information about this?. Thanks ------------------------------------------------------------------------ [2012-04-04 17:06:35] gufophp at gmail dot com Description: ------------ <?php echo round(33.29999999999999715783,4); // fail echo "-"; echo round(33.29999999999999715783,2); // fail echo "-"; echo round(33.29999999999999715783); //ok echo "-"; echo round(33.29999999999999715783,-1); //ok echo "-"; echo round(55533.29999999999999715783,-2); //ok ?> Test script: --------------- 33.29999999999999715783-33.29999999999999715783-33-30-55500 Expected result: ---------------- 33.3-33.3-33-30-55500 Actual result: -------------- 33.29999999999999715783-33.29999999999999715783-33-30-55500 ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=61624&edit=1